Adventures in Hydro #2 - LP Aero/NFT mash-up - or - switching to HPA?

You know, every time I think Im finally starting to, maybe, possibly, getting a handle on this whole buffer thing, you post something that proves beyond a doubt that I have no clue :smiley:

This is one of the reasons I like the idea of using the resins. On the surface, it seems like it bypasses most of the issues with all the other buffers.

I think I will email Dow and see if they will give any information. I found alink where you can ask for a sample. If I can figure out what sample would be best, I will see if they will send me some.

It looks like the UV light really does kill algae. It was time to top off the rez tonight. Im still short filling it and only adding 5 gallons at a time. I was not intending to do any cleaning as such other than clean the filters inside the rez. However, I noticed some odd looking ā€˜stuffā€™ in the water that I have not seen before. It looked like very thin tissue paper that had been shredded into mostly very small pieces. They broke up into smaller pieces every time I tried to catch some. The more I messed around in the rez, the more of that stuff there was. I finally noticed that if I rubbed the walls, floor of the rez, more of it came off - especially from the nooks and crannies where I probably didnt clean all that well last time.

Im pretty sure this is algae build up that is now dead due to the UV light.

So, I ended up doing a much more thorough drain and cleaning. I also drained the accumulator tank and did a mini flush of it at the same time.

After re-filling everything with the AN PH perfect nutes to an EC of 0.9 ms, the PH in the rez was at 5.5-5.6. I waited about an hour and checked the PH of the water from the accumulator tank, and it was up to 5.9.

So, my water is still going up in PH as soon as it gets pressurized. There could still be algae build up in the tank. Actually, Im sure there still is, so that could be part of the problem, but Im still curious if just the higher pressure alone is enough to change the PH.

Hey @SuperiorBuds - I know you are busy, but if you get a chance, can you test your nutes after they have been pressurized for an hour or so to see if you have similar PH changes?

I plan to do a really really serious cleaning before the next grow, but Im going to have to finish this run first. I dont think I can take the system down that long without hurting the plant.

On that note - does anyone have any suggestions for how to clean out old, probably dead, algae growth from inside the system?

I can easily kill it with strong chlorine and/or copper, but they dont actually remove it from any surfaces. I need something that will essentially scrub the insides of all my tubing, solenoids, accumulator tank, etc - without damaging rubber seals or plastic. I dont want to leave any dead algae in the system, but I would prefer not to have to buy all new stuff!

Unfortunately itā€™ll be a week or two before I can test this. I disassembled everything in the room to do a deep clean on all lines and fittings, then Iā€™ll be remounting most of the HPA components in my new res chamber. I also donā€™t have access to water outside right now, so thatā€™s another holdup. Hopefully soon man, Iā€™m going crazy not being able to progress while I wait on other people. (Both plumbing and electrical work need to be completed before I can take the next steps.) Couple that with -30 outside today and itā€™s rough getting anyone out here to workā€¦

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No worries. Im asking out of curiosity, not necessity, so no rush at all :slight_smile:

That is some serious weather. One of my daughters and her family live in Iowa. They are expecting minus 24F this week. Thats just nasty cold! brrrrrrr

This was just an hour ago. And many feet of snow.

Yesterday I brought the chiller and its lines in the house to clean them up. I setup the lines in the hottub and used the sprayer to clean them out ā€“ I had a TON of brown gook come flying out. Now Iā€™m not sure if thatā€™s from during the run or after the lines sat for a while, but the crap that came out of there was not pretty. Iā€™m flushing the rest of the chiller today to ensure thereā€™s nothing built up like that inside. Really glad Iā€™m switching to glycol and wonā€™t be running nutrients through the chiller any more. (And obviously I wonā€™t need the chiller for a few months yet, haha.)

Now like you I also need to find a way to flush the tank.

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Im need some ideas I can ā€˜borrowā€™ :slight_smile:

I want to cut waaaaay back on the pump that is stirring the nutes in the rez, because that seems to be driving my PH up much fasterā€¦

BUT - the nutes settle out over time, so they must be stirred periodically. I dont know how soon that gets serious, but I would expect an hour or so at minimum?

At the same time, the pump that tops off the accumulator tank only turns on roughly every 6 hours at current settings - but its not exact. That pressure pump is controlled by a pressure switch - not a timer. I dont want separated nutes getting pumped into the accumulator tank, so ideally, the rez would get stirred just before and during the time the pressure pump is filling the accumulator tank.

Ive been trying to come up with a way to have the pressure switch trigger the circulating pump in the rez one minute before the pressure pump starts. That will give the rez time to get mixed before the nutes go into the accumulator tank. It takes about 4 to 5 minutes to re-fill the accumulator tank. Once its is topped off, and the pressure switch needs to turn off both pumps.

The cycle needs to repeat next time the pressure switch kicks in.

My current idea is to use two timers - one for each pump - that are turned ON/OFF by the pressure switch.

That sounds easy, but its actually not. So far, the only timers I have found that will run a pre-programmed timing cycle on power up, are low voltage timers.

Sonoffs and every other timer I have tried, either wont auto run a sequence on power up OR they pick up where they stopped when the power went off. Neither one of those will work for what I want to do.

The low voltage timers I have will do that, but they dont do 110V AC. I could probably add some 110 volt relays and trigger them from the cheap timers, but Im hoping for a more elegant solution.

I could just wire the circulating pump so it starts and stops with the pressure pump, but then the pressure pump will have several seconds to pump separated nutes before the rez gets mixed properly.

Anyone have any brilliant - and cheap - ideas?

Arduino and a 5v relay block like the one in the other thread. When you power on an arduino it starts its program from the start as though it has never run before, no long term memory, just a program flashed onto the eeprom.

Runs on 9v and has 5V higher power signal outputs than a pi.

Pressure switch powers arduino, arduino turns on mixing pump, one minute later arduino turns on pressure pump then cuts power 5 minutes later. I assume some hardware cuts power to the arduino when tank is full.

EDIT :
For some reason the hash symbol before ā€˜includeā€™ makes it bold instead of showing as a hash symbolā€¦

include < stdint.h>

int pressurePumpPin=3;
int mixPumpPin=4;
int oneMinute=60000;
pinMode( pressurePumpPin, OUTPUT);
pinMode(mixPumpPin, OUTPUT);
digitalWrite(mixPumpPin, HIGH);
digitalWrite(pressurePumpPin, LOW);
delay(oneMinute);
digitalWrite(mixPumpPin, HIGH);
digitalWrite(pressurePumpPin, HIGH);
delay(oneMinute);
delay(oneMinute);
delay(oneMinute);
delay(oneMinute);
delay(oneMinute);
digitalWrite(mixPumpPin, LOW);
digitalWrite(pressurePumpPin, LOW);

while(1){
}

The ā€˜while(1)ā€™ shutdown loop at the end might have a bug but you should not need much more code than that. The relays handle 10A at 240V so should cope.

EDIT 2:

Just saw this, yeah this is the cheap way. All logic will work on low voltage and you will have the same issue of powering a high power device with a relay. If you get used to wiring and coding an arduino you will have a lot more functionality though, you can have an arduino monitoring your PH and EC and dosing them both at fixed values, turning a heater on when it is cold, all sorts of things with pretty much the same code repeated for a different pin and sensor. Sensors and relays from china are very very cheap for arduinos and surprisingly reliable.

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This is what Im going to do. Its by far the cheapest option I have seen so far that I am 100% sure will work. I did find a couple of 110V timer/relays that may work, but Im not 100% sure. The instructions for these cheap timers are not easy to read.

Yeah, I should get back to working on this. I still want to do a doser to control PH, but its going to be down the road a bit.

I am going to have to look into pressure sensors for Arduino. I like that idea better than the mechanical switch Im using now. It has physical limits as far as range, and its fiddly to set. You have to make an adjustment and then wait to see if its the pressure you want or not. It would be much better to just input a value and have it work. Plus its noisy as heck!

By the way, I forgot to thank you for the programming help you offered in the other thread, and now I need to add an extra thanks for the help this time, so thanks!!! :slight_smile:

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Thank you for the thanks, but in return, I thank you for these threads exploring cutting edge growing. I now think about PH in a subtly different way.

What are the max/min pressures?

A BME280 will be fine between 300 and 1100hPa

If you wanted to splash out and go fancy, a BME680 (Ā£20) will do pressure, temperature, and humidity. It will even tell you which gasses are in your airā€¦

the BME680 integrates for the first time high-linearity and high-accuracy gas, pressure, humidity and temperature sensors. It consists of an 8-pin metal-lid 3.0 x 3.0 x 0.93 mmĀ³ LGA package which is designed for optimized consumption depending on the specific operating mode, long term stability and high EMC robustness. The gas sensor within the BME680 can detect a broad range of gases to measure air quality for personal well being. Gases that can be detected by the BME680 include Volatile Organic Compounds (VOC)

Yes, it is 3mmx3mm and less than 1mm tall. You get them on breakout boards like this one. And yes, it can detect ā€˜volatile organic compoundsā€™, or smell in other wordsā€¦

The sensor is the little metal box near the top. The code is just a matter of finding and downloading the library that someone has already written for the particular breakout board you have then using the commands they tell you to talk to the device to get data.

For example, to use the BME280 you include the commands

[hash symbol]include "SparkFunBME280.h" (this is the library for the sensor)
[hash symbol]include <wire.h> (I2C library for communication)
    BME280 mySensor; (tells the program that every time you use 'mySensor' it knows to talk to the BME280)
    mySensor.settings.commInterface = I2C_MODE; (sets the BME280 to I2C mode for communication)
    mySensor.settings.I2CAddress = 0x76; (tells the computer the address of the BME280)
    [there are a couple more settings you can customise your BME280 with like 'smoothing' but I will cut those for brevity]
    mySensor.begin(); (start the sensor)
    Wire.begin();  (start the I2C serial bus to talk to the sensor)
    delay(10); (to allow the sensor to wake up)
    pressure = mySensor.readFloatPressure(); // mBar is this value/1000 or something
    airTemp = mySensor.readTempC();
    humidity = mySensor.readFloatHumidity();

now you would have your pressure, temperature, and RH% as variables in your code so you can act on the numbers by changing outputs from LOW to HIGH, setting timers etc. I think it does pressure in hPa but conversion to PSI should be easy.

I have missed out some commands, things to turn on the I2C wire etc but these are the commands you would need to get the pressure, the code in the other post will turn stuff on and off. These days you can almost program using cut and paste. If you donā€™t want it to do anything too obscure, someone has already written that codeā€¦

EDIT :

Sounds like what you really need is just a delay circuit and a relay, basically a tuned circuit that turns on a logic level output after a set time. Each power on starts the cycle at the same place. With just one you could turn on a pump using the pressure switch to mix, then turn on another pump with the delay after a minute, then they both turn off when the power is cut.

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I believe Larry is talking about water pressure (PSI) so he can trigger the pump based on the pressure in the lines.

Something like this would work though.

https://www.dfrobot.com/product-1675.html

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Thanks for that code example! That exact sensor isnt the one I need for this exact situation, but it looks like a very useful one to add at a later time, so Im going to save it!

I need a sensor for water pressure between zero and about 150 PSI max. The one @SuperiorBuds linked to is the right type, but it would be better if it was stainless. The DFRobot one doesnt say of its stainless or not, so I am assuming it isnt stainless. I did find some stainless versions like this one.

https://www.amazon.com/dp/B0748CV4G1/ref=biss_dp_t_asn

Yes, thats it exactly. BUT - Im not at all as sure as I was that this will actually help my PH issues.

Ive been tracking PH more closely over the last two rez re-fills. Before that, I was circulating/mixing the rez one minute out of every five minutes. I changed that to one minute every hour.

However, I cant tell that that change did anything. The PH still goes up just as fast as it did when mixing more often.

It occurred to me tonight, that if there is a C02/carbolic acid cycle going on here, then the C02 is going to out-gass or equalize with the air in the room no matter what I do. It may slow down or speed up depending on the circulation rate, but the C02 is going to do its thing no matter what - probably within just a few hours even with no stirring.

From what I can see, it makes no difference no matter how fast/slow/often I circulate the nutes. So, I dont think my idea for the delay timer triggered by the pressure switch is going to do anything significant for the PH.

I have about decided that my system is just too contaminated with old dead algae in the rez and old dead or alive algae in the rest of the system. It seems to me that is the only thing that could be causing this PH rise to continue no matter what I do.

However, I do really like the idea of an Arduino controlled pressure switch that will allow me to set exact on/off pressures for the pump. I spent over an hour the other day trying to lower the pressure range just a bit without loosing the spread between on and off pressure. I never did get it exactly where I want it. Plus the setting points seem to drift sometimes, which is irritating and worrying.

So, an Arduino based pressure switch for the pump is a definite thing to do. Im thinking it would be best to start building a setup that could be expanded to also handle PH monitoring, dosing, grow light timing and maybe even nozzle timing?

Can you guys suggest which Arduino to start off with that could handle just the pump/pressure switch - the cheapest option to get me started.

Then, what would be the minimum option for a full control system that could - way down the road - do everything? If there isnt a big difference in price, I will just start with the better main board.

I have found that as the complexity of my system increased, so did the frequency I needed to monitor and adjust it. Like the difference between your daily drive Datsun and a top fuel drag car. Sure the drag car performs better but it needs a lot more maintenance.

When I just had a tank pushing solution past some roots I checked it every day when I was there, but I was often away for up to four days. As you may guess, my plants were not happy.

Now I run RO and have made many other changes I am more aware of the changes in my tank and how they affect my plants. I found the frequency I needed to dose was more than a person could do. The PH would wander too far just while I slept. Now I monitor and adjust every minute if needed.

I think you are right that you are at the point where you need to automatically take care of some of your growing.

If you want to start with Arduino then it is a good place to start. They are very very cheap and will scale up with your knowledge.

I use them in combination with a Raspberry Pi which runs a 7" screen to show data although you can run an LED number display right from an Arduino (for when you want to see PH, EC, pressure etc). I also use it to store the code and to inject the code into the Arduino.

But none of that is needed right now, you can start by just setting the Arduino to do the right thing and letting it run with no display.

As such, there is no ā€˜better main boardā€™ to buy, you will be using the same boards, the same code, which is handy. In fact, later when you are more familiar, the boards are cheaper.

That transducer looks to be just what you need. Outputs linear 0.5-4.5V and you can connect that (with a 10K resistor) straight to an input on your Arduino and read the values very easily.

The code will be as simple as the code I have already posted. Obviously get a sensor capable of double the nominal pressureā€¦

Once you connect your first sensor and have readings from it control your first device, you will know 90% of what you need to build your entire system.

For your very first board, I would suggest one that you can use with jumper wires and a breadboard so you can redesign without having to get the soldering iron out.

Like this

It is a bit bigger, and you can fit jumper leads into it instead of having to solder it in.

The code is the same, everything is the same, but it is better for prototyping.

Later, when you have it working, you can get the nano, solder it, and put it into a neat tidy box.

You will still be using arduinos, but cheaper and smaller ones.

I would say the best option to start with is not the cheapest option but the expensive option is still only $12.


One of these, one of the Arduino, the sensor, and then wires. (and power supplies to power them all)

EDIT :

You will also need a PC or Mac to program the Arduino of course.

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Itā€™s strange that you have drift in your cutoff. Which pressure switches are you using? I just picked up 2 spares, both factory configured to cutoff at 100psi for under $20.

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Excellent! Those are very affordable options. I can afford to order those boards fairly soon and get started on the programming aspects. I can get the sensor and other parts that might be needed a bit later.

That particular sensor I linked above has terrible reviews, so I need to find another option. I think I will likely need a pressure snubber as well. My pumps are solenoid type pumps, so I know there will be significant pressure spikes to deal with if I dont use a snubber to smooth them out.

Thanks!!

I have been running with a max pressure cut off of around 135-140 PSI with a cut ON pressure of about 120-125. My tank is rated to 150 max operating pressure, but I wanted to stay well below that.

I like the cut ON setting to be well above the pressure reducer setting that feeds the nozzles. My reducer gets sloppy when the feed pressure is too close to the nozzles pressure.

The switch Im using is a cheap mechanical switch. There are several variations for different on/off pressures.

http://www.dwyer-inst.com/Product/Pressure/SinglePressure/Switches/SeriesCXA?Query=CXA-S3

These are regular well head pump switches, and have brass fittings, but the only SS versions were way outside my budget.

They adjust settings by the pressure on a mechanical spring/screw setup. The drift I see could easily be the cheap pressure gauges Im using too. Plus, its not that much and it never gets far out of range - maybe Ā± 5 PSI.

Im much more interested in being able to set the two different pressures more exactly. You can regulate how often your pump cycles and how much liquid is stored in your accumulator tank by playing with the two pressures.

With the mechanical switches, you have to guess where the pressure is set to cut on/off, then fill the accumulator tank and note where it cuts on/off. Then you adjust the screws, drain and re-fill the tank. It seems to take me several drain/fill cycles to get things close to where I want - which is a lot of trouble and time.

If your switches are set to 100 PSI, what pressure are you running out of your reducer to the nozzles?

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Iā€™m not running a pressure reducer at all. Whatever the line/tank pressure is, thatā€™s what hits the nozzles. I run 80-100psi.

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Ah, you told me that before and I keep forgetting :slight_smile:

Of course, the downside to that is the mist quality (droplet size) and flow rate will be constantly changing while the pressure is changing. You will get smaller droplets, but higher flow rates at 100 PSI, and larger droplets, but lower flow rate at 80 PSI. It might be a good idea to flow test at both pressures just to see how big the difference is. You might need to take an average of something when it comes to calculations. I have no idea what the difference might be - Iv done all my testing at a constant pressure.

On the other hand, that may not really be that much of an issue - especially in your case. At the flow rates you were running before, your pump must cycle a lot more often. Faster cycle times should tend to even things out I would think. As far as I have heard, those pumps are pretty bullet proof, so higher cycle rates shouldnt be an issue there. Plus, the smaller nozzle openings your using may not be as sensitive to pressure changes.

Feel free to ignore all my rambling - Im half baked :slight_smile:

I was considering switching to a diaphragm type pump at some point to reduce noise, but now Im vaguely remembering the normal 5000/8000 series wont go above about 120 PSI? I cant remember now, but I was wanting higher max pressure so I could have a larger differential between the min/max pressure so I could lower the cycle rate on the pumps.

That might be worth considering if you are subject to power outages very often. You can run the solenoids and timer for many hours from a small 12 volt battery, but your pump will need a much bigger back up power system.

That is something I have been intending to do, but have not gotten around to yet. I have a battery, wiring, and switches to do it, but no automatic relay. I would have to wire it all up using flashlights if the power were to go out suddenly :slight_smile:

Im not toooo worried about it even though I probably should be. Our power hasnt been off for more than a few minutes in three or four years at least.

In other news - it occurs to me I have mostly been posting BAD NEWS items. So, I want to shout out another big thanks to @Northern_Loki for the donated RO filters and @MicroDoser for additionally nudging me to make the switch to RO.

Since the switch, I have had zero zombie algae apocalypse ā€˜brown outsā€™ on the roots like I had earlier. I am sure its the RO water mostly, but the UV light is probably helping as well. I know its killing something in the rez anyway.

I cant decide if this next thing is good news or not, but the roots are growing really well - a bit too well. Im loosing two more nozzles to the roots, and the duct tape roots are getting out of control. Im going to have to get in there and do some root trimming again and move at least two nozzles again. The top of the chamber is so full, I can no longer get my hand anywhere near the back 2/3 of the chamber or into the bottom section - unless Im willing to crush a lot of roots. So, no more ā€˜root tourā€™ videos. Its getting more difficult to even get regular pics of the roots for lack of room. Im guessing Im somewhere close to or over 30 gallons of roots at this point. The lower mat is in full contact with the umbrella in several places as well.

As far as I can tell, this isnt a major issue at this point. I dont smell any root rot and cant see any drying out anywhere. I can only assume the roots are wicking moisture from where its being sprayed to where its not - at least enough to keep things going. At least thats my hope. I cant see or feel anything in 2/3rds of the chamber though.

Im hoping I can get this root mass out in one piece and get some decent pics of it.

In the mean time, here are a few pics as best as I can get.

I just noticed there is a big ass tap root growing UP into the duct tape!! Now Im starting to worry about the strength of my root chamber lid! The lid is just 1" thick foam circle 24" in diameter with a single piece is aluminum bar as reinforcement. If that root breaks the bond between the foam and aluminum bar, the whole plant could drop into the chamber!!

I decided to trim some roots back up top to free up one nozzle, but I stopped. I would need to trim out at least a gallon or more to do any good, and Id rather not do that - yet. Plus, Im worried about the extra damage Im doing by handling and any cut pieces that drop in the chamber could be a source of rot.

Im going to make up some root creamā€™ and see if it works on my arthritic joints.

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I topped off the rez last night. Unless I siphon it out, there is always about 3 gallons left in the rez when it reaches the drain port.

This time when I topped off, I did NOT drain all that out. I just added about 6 gallons of RO water and enough AN nutes to get back to EC 1.0. PH was holding last night at 5.6.

This morning it was up to 5.7 and tonight it was up to 5.9.

So - two things:

  1. running these nute below the recommended concentration is not working nearly as well as far as buffering the PH. If I do the recommended dose, the EC runs in the 1.5-1.7 range - and I got a lot of tip burn when I did that. BUT - the PH holds for two full days.
  2. Adding to old nutes in the rez that have lost their buffering action, accelerates the PH rise.

I am less and less impressed with these AN nutes over Mega Crop - especially for the cost difference. I got my sample of MC v2 a few days ago. I think I will switch back next time I top off and see how it does.

Oh, i ordered 1 quart of 85% Phosphoric acid to try instead of the sulfuric I have been using. Im really eager to see if using a ā€˜weakā€™ acid works better than a ā€˜strongā€™ one.

I diluted it 4 to one, but that ended up a lot stronger than my sulfuric or my old GH PH Down. That meant I shot the PH down to 4.9 with the first small addition. I decided that was too low, so I added some Potassium Hydroxide PH Up.

So, I have confused the issue by adding a strong base and a weak acid - which may have some buffering action.

Either way, it will be interesting to see if there is any change in the PH rise rate.

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Is that a thing that works? I am starting with that, my family on my motherā€™s side get crippling multiple joint arthritis around 50-60ā€¦

Luckily, I have access to plenty of cannabis roots, hehe. I will have a look at one of the tincture and cream threads.

Yeah, the 85% is pretty effective at lowering PH. In my 100l tank, using tap water, it takes about 15ml. Using RO it takes much less. I dilute it 1:10 before I dose with it, makes it much easier to hit the target.

Sounds like you are hitting the same problems I had with my system. It is so good at allowing root growth that the timings I did before regarding veg time etc were far too long and the roots ended up far too large, to the detriment of the plants.

I ended up (after about 3 years trying to tame a new, very vigorous clone) settling at 8-10 days veg then straight into flower. Any more than that and by mid-flower, the roots were far too large and leaks happened where the roots were just filling the gutter and nutrient solution was flowing over the sides.

In your case, I would worry about getting a place in the middle of the roots which is not getting sprayed. Maybe a nozzle right at the stalk at the top for some Reagan-era style trickle down?

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Haha no worries, sometimes I have to talk (type) something out before my brain reaches a conclusion too. :slight_smile:

Like you said, the Aquatec pump I am using is pretty bulletproof. There are plenty of people running full RO systems and HPA setups w/ no accumulator using this pump with very low failure rates. These things are good for 30k hours of continuous usage and can pump up to 160 psi, plus I have a backup just in case.

I had thought about a pressure reducer to standardize the flow, but when testing I noticed thereā€™s very little (if any) difference w/ the nozzles between the top and bottom pressures. Like you said it could be my nozzle orifice.

I live in the middle of nowhere, so our power goes out constantly. In fact, it went out twice last night. Luckily I have thisā€¦ :slight_smile:

This is the point I was at last time where I started to freak out due to dry areas in the root zone. Itā€™s also why I added the secondary E&F feeding system for the lower portion. Itā€™ll be really interesting to see what the roots look like w/ HPA only after getting so big.

Yikes. Another one of my fears right there. I struggled to figure out how to build the ā€œlidā€ ā€“ strong enough to support the plant above, the roots hanging below, and still be safe from chemicals for them. I ended up with 3/4" MDF coated in pond shield because I knew it could handle whatever grew above it and the pond shield is safe for fish/plants without leeching any bad stuff. (Flex Seal will kill fish if used to line a pond, so I didnā€™t want to use anything like that exposed to my plant roots.)

The roots are looking good though! Getting to the really exciting part now!

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I think this is where it starts. Earlier in the thread they also mentioned that it can help with nuropathy. I have diabetic neuropathy, so Im interested for that reason too.

Yeah, I ended up diluting it another 25% and thats better, but still kind of strong.

I suspect this is what Im going to have to do as well - much shorter veg time. On the other hand, Im seeing no real problems with the over sized root mass - so far. It will depend on how things end up over the next 3 weeks or so till harvest.

Im may try two plants next time and let the roots just mix together and see what happens. Im not sure that will solve the problem though. If it takes 30 days of veg to fill a screen with a single plant, then it should only take 15 days with two plants - BUT - two plants have twice as much root volume, so I dont see that as a real help. Plus, the first few days of veg dont really do much, so you cant really cut back that much if you need to fill a scrog screen - can you?

Yeah, that was a concern a while back when I lost the first nozzle. Thats partly why I moved them to the top of the rez - I figured the water could more easily trickle down than it could wick up from below.

I cut into the root mass a good bit trimming some of it back, and the inside looks fine to me. No fuzzies, or I should say the fuzzies go away the deeper you go into the root mass. Way inside, there is just no room. The roots are packed in pretty tightly just a couple of inches inā€¦ But, they look healthy to me as far inside as I can see.

Wont know for sure until I can get the whole thing out and take a good look.

LOL yeah, thats me sometimes for sure!

They will do 160 psi? I thought they topped out at around 130. I didnt want to run it at max rating, so thats why I decided not to switch over from the solenoid pumps. If they can do 160, then it should be safe enough to run them at 130 or so.

After our last talk about the pressure switch drifting, I realized why it is so noisy and probably why the values seem to drift at times. Im pretty sure its the pressure spikes from the solenoid pumps.

Once the solenoid pump switches ON, they are a bit noisy all by themselves. However, when the pressure gets back up close tot he cut off point, the pressure switch starts to vibrate noisily maybe a minute before cut off.

I just looked at it closely while it was doing that and I can feel that the vibration rate at the switch matches the vibration rate of the pumps. Im pretty sure the pump spikes are triggering the switch to momentarily cut power on the surges, then it kicks back on when the pressure lags between pulses.

I went ahead and ordered a pressure snubber to see if Im right. If this is what is going on, it cant be good for the switch to be turning on/off 60 times a second or so like that. Im sure it will reduce its life expectancy if nothing else.

In addition to the snubber, I have all the other parts picked out to build the Arduino timer/relay setup, but Im going to have to wait on that until after the harvest. I have several things I will need to replace or re-build before the next grow, and those need to be handled first budget wise. The arduino stuff will be a very nice up-grade, but itsnt as critical as re-building lids, and replacing algae contaminated plumbing and adding more nozzles.

Yeah, as long as you have consistent flow rates and hang time between upper and lower pressures, then dont see any problem.

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