LED HPA Grow Room šŸŒ± šŸ’§ šŸ”Ø

Indoor Growing Hydroponics
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I was just looking back through your thread to see what pressures you were running at and came across this.

I thought the same thing as you at first, but I changed my mind after using it for a while. I thought it wasnt staying calibrated at first, but it was always close enough when I checked it - meaning the IN and OUT were always within a few points of each other. Maybe 2% difference between them at most.

Then I read that the calibration needs adjusting if there is no flow or really low flow rates. However, there is only a very small change at the flow rates Im running at.

For example, right now my system is running at .7 seconds ON and 50 seconds OFF which is about .7 gallons per day flow rate. The meter is reading 336 on the IN and 348 on the out. Both fluctuate a point or two every so often - but not exactly when the nozzles fire.

When I change the cycle to .7 sec ON and 2 seconds OFF or 25 times the flow rate = closer to 17 gallons per day, the IN reading drops from 336 to 335, and the OUT reading drops down from 348 to 344/345. So not a big change at all. Its actually not much more variation than what I see when there is no flow at all.

I dont really care what the exact, or absolute value of the readings from the HM are anyway. I get that reading from the rez using my BlueLab meter. The HM meter is more to track the ā€˜differenceā€™ between the in and out rather than the actual TDS value. It seems to be good for doing that.

I monitor the rez when Im making changes to the nute concentration, but pay attention to the difference between IN/OUT to check how the roots are feeding and if I need to raise or lower the EC in the rez.

So far - with almost no roots in the system - that difference of 8 to 12 points is holding pretty constant. The only time it changes is when I forget to turn the heater for the root chamber back on after I have been working on the chamber.

I have the root chamber heater set to keep it between 68 F and 70F. When the root chamber is cooled down to 65 F or below, there is less difference between the IN/OUT readings. Im sure whats happening is the droplets evaporate to some degree while they are suspended. A warmer root chamber makes for faster evaporation. That in turn increases the concentration of nutes left in the droplets that collect in the bottom of the rez and raises the TDS reading on the OUT probe.

Once the roots get bigger, I should be able to tell how they are feeding by watching to see if that IN/OUT difference goes up or down. I hope :slight_smile:

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Very cool read, well I wonā€™t lie I couldnā€™t read it all in one sitting but it appears by the end Iā€™ll have a full understanding what Hpa is. Which is why I started the read in the first place lol so thanks keep up the good workšŸ‘šŸ»

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I was finally able to get a good close look at the roots of the OC and as I suspected things were not goodā€¦not good at all.

I knew the roots were off-color, with new roots turning brown within a few days. When I was able to sit down and really pull them apart I found some ugly slime down there. I think my initial problems only bred more issues as I went along ā€“ Iā€™m actually surprised that I kept these alive after checking the roots. (Another benefit of the dual-zone system.)

Luckily they did survive and in the end the OC produced over 2x the amount we normally pull from the same plant in soil under HPS.

Final numbers for the BK are not ready yet, since itā€™s drying a bit slower than the OC did. But the OC ended up with 520g of dry flower (just over 18oz). The smoke is smooth with a pure white ash and produces a stronger high than normal.

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There were tons of smaller popcorn buds all over that really added up. Next run Iā€™ll be going back to a fully trained plant to try and eliminate some of the fluff and move that energy up to the primary colas.

As for the root rot, I have already added a powerful chiller to combat this but Iā€™m going to change how I route that next time. Iā€™ll be adding the wort chiller and a dedicated pump that can slowly circulate a separate cooling solution instead of attempting to run the nutrient solution itself through the chiller. I am also going to revisit the root zone tubs, ensuring that they are 100% light-proof. Finally I will be adjusting the spray timings quite a bit and doing a lot more measurements to ensure Iā€™m getting proper flow ā€“ before I get the clones in place.

Thereā€™s some other minor changes coming to the room as well, but Iā€™ll discuss those as we get going. Once I jar up the BK I will get the room back and itā€™s tear-down and rebuild time.

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:+1:

I really like the ā€œglycolā€ chiller concept for several reasons. 1) keeps a neural solution within the cooling loop and avoids building up of anything unwanted in the hard to clean loop 2) allow precise control of temperature 3) can have several independent cooling loops when integrated with a glycol reservoir.

If you have a glycol reservoir (or an independent pump), can I suggest considering a PID controller to control the gylcol pump. Iā€™ve tried something similar and, with some minor pid loop tuning, have been able to regulate the solution temperature to within 0.5 degree F in the heat of the summer. This was for RDWC, in my case. Not that anyone needs that level of control, but it certainly helps my OCD :smile:

I had promised @anon32470837 some time ago that Iā€™d post some photos of what a glycol chiller with a PID controlled reservoir looks like but Iā€™ve been too lazy to get to that. Sorry Larry. Let me know if that would be of useful and Iā€™ll post some photos.

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It turns out that my fabric pot root chamber actually needs heating rather than cooling. It runs a good 7-8 deg F below room temp, and I dont grow in the summer, so I no longer need a chiller. BUT - pics of tech stuff are always interesting, so I would still love to see the details. :slight_smile:

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Totally agree with those points ā€“ I also like that I can control the speed of the nutrient solution separate from the cooling solution speed. Chillers work so much better at slower flows, but I need to move a lot of nutrients with the changes that are coming so this just made sense.

I hadnā€™t thought of a separate speed controller for the cooler pump. Iā€™m a sucker for control, as well, so I might have to dig into this a bit deeper and see what I can throw together with what Iā€™ve got here.

Iā€™d love to see photos of how youā€™re cooler is setup. Everyone sees and does things differently, so I love getting a fresh perspective on things. If Iā€™m not constantly innovating, changing, and tweaking things I get bored. :slight_smile:

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Youā€™ve given me another diversion for the day. :smile: Iā€™ve posted some pictures of an experimental glycol chiller, here: RDWC Glycol Chiller Experiment

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Interesting. You sure couldnt tell that from the root pics you posted earlier. I figured the brown color was just normal color from the nutes.

I forget - were you running a sterile rez or using bennies of any type?

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I assumed the root color was nute stain at first, too. Until I got my hands on the innards. Yuk.

Last run was really a bare-bones test to compare LED vs HPS and HPA vs soil, so no bennies at all. I also wasnā€™t running a sterile res unfortunately, but Iā€™ve already got my HTH ready for the next run. I am not fighting that crap again. :slight_smile:

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The bear klaw was finished up last night, trimmed, and hung to dry. Not nearly as much off this plant as the OC, but itā€™s a great smoke.

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One thing that is strange to me with this one is some of the colors. Some of the buds are straight up purple while most have the familiar bright green that BK is known for up here. And even stranger, some of the buds are purple on one side and green on the other. Weā€™ll be running these same strains again the next run so I can compare, but anyone have any thoughts on the coloring? (Iā€™ve got my assumptions, but I wanted to hear from the community first.)

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I have no clue about the coloring. Were those oddly colored ones all near the top or bottom? Were the dual colored ones somehow shaded?

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They were pretty much spaced all over, just random branches. I didnā€™t notice any shading from above but with some of them being dual-color my initial thought is that it has to be light/shade related.

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Light spectra, that would be my first thought as well. Anthocyanin development?

Purple, not brown right?

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Correct, they were purple. I hadnā€™t thought about it, but the plant that showed this was next to two outside walls ā€“ so perhaps it was a bit colder in that corner, tooā€¦ Just spitballing here really, but weā€™re moving the entire set of beds into a more central location of the room for this next run, so hopefully that can eliminate some of the variables.

ā€“

We have started to clean up the room from the last run ā€“ and there are lots of good lessons to be learned from taking this to the end. The OC had developed some extensive root rot in the center of the root mass while the BK had stained roots, there was no rot, slime, or smell. I am going to attribute some of this to my nozzle placement causing excess water build up. I had the nozzles far too high in the chamber and this was causing quite a bit of spray to hit the bottom of the lid. This caused build-up, which then dripped large drops directly onto the roots. Couple that with too frequent of a spray and some dirty PVC and I think that all added up to problems. Iā€™ve picked up some HTH pool shock and will be running a much cleaner res / system next run.

I have ordered quite a few new products for the next run.

New Aeromist nozzles, the same ones @anon32470837 is running now w/ swivels.
https://www.aeromist.com/low-pressure-ss-303-anti-drip-misting-nozzle-024-x-10-24.html
https://www.aeromist.com/misting-nozzles/nozzle-extensions/nozzle-swivel-connector-10-24.html

I have also picked up some new tees for the nozzles and will be picking up some 1/4" SS tubing to replace everything after the solenoids. Speaking of solenoids, I picked up 10 more so I have some spares and so I can go ahead and switch this from 1 per 4 nozzles to 1 per 2, with a much shorter (8") run.

Weā€™ve begun reworking the feed lines, as well. Before I had a single 3/8" polyethylene line that split into 3 1/4" lines ā€“ one for each bed. With the rework on the solenoids I wanted to ensure I had stable pressure all the way down the system, so weā€™ve ordered a bunch of 1/4" John Guest to 3/4" NPTF fittings. This allows me to run a pressurized 3/4" PVC line all the way down with standard PVC tees to feed each solenoid. This should give me much more stable pressure.

The last piece of the puzzle will be hooking up the new res and pump that will recycle the water through each bed and back into the res. This will act as both a root zone cooler as well as a way to handle the heavy feeding that takes place later on in the plants life. (This replaces the E&F secondary zone I had setup last time to keep the big girls alive.)

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While I was away the new batch of solenoids arrived.

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Along with the nozzles, swivels, and tees. (Youā€™re right, @Larry3215-- Aeromist ships quick as hell.)

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The tees I found seem to work, but weā€™ll see how they do under pressure.

I was also able to finally pick up my latest reservoir while I was travelling, since everyone was out of stock up here.

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I still have a few plumbing items to pick up but at this point most of the items are on hand and we can begin the rebuild this week.

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Nice! Dont forget - you might want to keep those solenoids under about 118 PSI. Ive had no more failures since dropping down to under 110 PSI max with the pressure reducer.

My new nozzles were due in today, but are a no-show :frowning:

I will be sticking the C99 seed in my system shortly, so better get ready :wink:

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Good thing to remember for sure. I run at max 110 so I should be good, but you having one fail really made me double-check me backup supply. I now have 4 spare solenoidsā€¦just in case. :slight_smile:

Haha for sure man. Looking forward to it ā€“ I will say youā€™ve really done a good job dialing in your stuff lately though, hopefully I donā€™t have as much of a rough start this time as last. LOL.

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Iā€™ve been contemplating this statement quite a bit lately.

To head off any problems I wanted to make a simple list of thoughts to consider for healthy roots. If anyone disagrees with anything or feels I missed something important please chime in.

  • Roots need O2 (air exchange)
  • Roots hate light
  • Root zone temp matters
  • Too much airflow will cause air pruning of roots
  • HPA mist will escape if you have big leaks
  • Contaminants in the root zone can lead to rot or other problems (pests)

Since my root zone is a sealed chamber with a PVC drain back to the reservoir I believe the only issue I will have to focus on will be air exchange. When I originally designed this I had assumed that the highly oxygenated water going through the nozzles would provide enough O2, but re-reading Atomizers threads got me thinking this probably isnā€™t enough.

This next iteration of the system includes a constant waterfall travelling down 3 sides of the chamber, across the bottom, and out the drain. This is the same water from the reservoir and is meant as a way to cool the root zone and provide a secondary heavy feeding source when roots reach the bottom. While this will provide a source of dissolved oxygen once the plants reach that point it still doesnā€™t help circulate the air in the chamber itself.

I kept reading the different ways people handled the air exchange when I came across a discussion about maintaining positive pressure inside of the root chamber. I already have a good outlet for excess air via the drain so I started thinking about ways to introduce fresh, clean air into the chamber without creating too much airflow to cause pruning.

I already have a good air pump running to the reservoir and it just happens to have an adjustable manifold on it with extra ports. As a test I went ahead and picked up a few items to play with.

Since I will want to be sure the air Iā€™m introducing is clean I picked up some cheap little in-line HEPA filters.

Then another manifold so I can restrict the airflow even further after the filter.

Right now Iā€™m not sure how Iā€™ll introduce the air into the chamber, but Iā€™m thinking of a diffuser ā€“ perhaps turned upside-down so thereā€™s not a constant flow hitting the lower roots.

As I was writing this up I noticed @HappyHemper and @MicroDoser discussing this very thing over on Larryā€™s thread.

So now I think Iā€™ll have another fun test to play with during this next run. I plan on running the same two clones again so I can compare vs this last harvest, but maybe Iā€™ll add a second BK in the third bed and use that to play with air. Or maybe Iā€™ll just go all-in, who knowsā€¦

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Interesting idea. Im in a rush at the moment, so just a quick first thought - I think you will need to have some way for the ā€˜fresh airā€™ to be at or near 100% humidity, before it goes into the chamber, or you risk drying the roots out.

I think the diffuser idea is good. Id make it as large as possible to spread out the fresh air and keep the flow rate low.

More laterā€¦

Oh, one more quick thought on your root temps - I wonder if your runs of 1/4 tubing were pre-heating the water before it got to the sprayers?

The water in the tubes would tend to be at least at room temp by the time it moved from the warm rez (no chiller in the HPA rez?) to the nozzles, plus the lights would tend to warm up the dark tubes even more.

Ive been racking my brain trying to figure where your higher chamber temps could be coming from, and thats the only thing I could think of.

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Ah very good point, hadnā€™t thought about that. That does bring up another strange idea though. :slight_smile:

I just got back from visiting my mother and you mentioning air humidification made me think of her oxygen machine. Itā€™s just a low-flow bubble humidifier built into those things. Itā€™s cheap enough it might be fun to play with, plus I can just fill it from the RO feed.

https://www.amazon.com/gp/product/B004UTQ4NE

I do wonder if flipping it upside-down into the flow of water from the sides would help, too.

I think it was either this or from sitting in the pressure tank too long. I am going to reduce the runs this time around and maybe I can shield the whole thing in bubble-foil to keep temps down. I do run a chiller on the res, though even that is getting a slight rework this time around. (Separate loop running propylene glycol.) I have also painted the outside of the chambers in a flat black and then covered that with a bright white, plus theyā€™ll still be wrapped in insulation.

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