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

[SuperiorBuds]

I had the pH problem with my well water as well. The first two runs w/ my ebb and flow system were nightmares of up and down fighting, twice a day. I finally solved the issue by increasing the volume of water and switching to Ionic nutrients.

Ionic Premium Single-Part Plant Nutrients for Growers

When I had the same issue with my aero setup I was already using the Ionic line, but I think it was the lower EC that was preventing the nutrients from buffering enough. Since jumping back to the bigger reservoir and increasing the EC for flowering things have been stable every day.

[anon32470837]

Interesting. I couldnt find any ingredients they add specifically as a buffer. They say it the ‘large molecules’ they make that keep the PH stable. That doesnt match up to my 30 year old chemistry knowledge though. I dont recall molecular size having anything to do with PH. Its a simple chemical reaction - you just need the correct chemicals - acids and bases.

Im going to have to do some searching when I get time.

My seedling in the puck is driving me nuts. It looks just fine and the root looks just fine - but neither one is growing. The other two seedlings, that I started a day later, in the dixie cups, are almost twice as big, and have a lot more root structure.

It has to be the PH I think.

[anon32470837]

I did some more checking.

I topped off the rez yesterday and PH’ed it to 5.7.

When I checked everything today:

The rez was at 6.4.
The run off container under the root chamber was at 6.8.
I drew some water from the accumulator tank and it was still at 5.7.

The only thing I can think thats causing this is agitation/aeration thats going on in different places.

The rez gets circulated for 2 minutes every 6 hours. Im assuming that is why the rez is going up, so Im going to stop circulating for a day and see what happens.

The accumulator tank water is mostly just sitting there not moving, so its not changing.

The only thing that makes sense for the runoff water, is that the action of atomizing the water, and spraying it around, must also be raising the PH.

Im not sure what to do about that other than try lowering the PH in the rez and tank, and see what happens then.

I think I’ll try running the tank and rez at 5.0 and see what happens to the runoff.

[anon32470837]

Well, thanks to an unfortunate equipment failure - one of my solenoids stuck OPEN - I have confirmed my theory about the spraying action causing the rise in PH of the runoff water.

I finished topping off the rez and dropping the PH down to 5.0-5.1 range and re-filling the accumulator tank, and stopped for a break. I had cleaned out the collection container under the rez and was all set to wait until sometime tomorrow to see if the lower PH in the rez changed the runoff PH. Just as I was starting a snack in the microwave, I heard the pump kick on. WTF? It had only been maybe 40 minutes since it got topped off. I ran back in and couldnt find any leaks until I looked in the root chamber and saw one nozzle continuously spraying. It took about 15 minutes to swap it out with my extra solenoid and I was back in business.

So I collected the fresh runoff water, and compared that to the rez and water from the accumulator. The rez had climbed up to 5.3 and the accumulator was at 5.2. The runoff was at 5.8.

Appearantly, just the action of spraying the nute water through a nozzle is enough to raise my PH from 5.2 to 5.8.

I was not expecting that, but I should have guessed it could happen from the way my water acts when you just shake up a jug.

So, from now on I will have to mix my rezs so the PH is down around 5.0, and do very little stirring of the rez.

If this works, I will be happy enough. After an hour of searching on Google I came up empty as far as finding a safe way to buffer the PH, so this is good news - sort of

[anon32470837]

Wow! I guess PH really is important!

I checked the roots on the seedling about 6 hours ago, and no change other than some very small side nubbins on the one root that was showing. Shortly after that, I started dropping the PH down in the rez, so the roots have had a better PH level for maybe a little over 4 hours or so. I just checked again, and there is now a new root showing that is almost as long as the old one, and the old one has sprouted 5 or 6 nice side shoots!

I was just about to toss that one and try one of the ones in the dixie cups too. Glad I got side tracked by the solenoid/PH thing.

[SuperiorBuds]

@anon32470837

Interesting. I couldnt find any ingredients they add specifically as a buffer. They say it the ‘large molecules’ they make that keep the PH stable. That doesnt match up to my 30 year old chemistry knowledge though. I dont recall molecular size having anything to do with PH. Its a simple chemical reaction - you just need the correct chemicals - acids and bases.

It not so much the size of the molecule, but the complex makeup itself. When nutrients are bonded like this they can reach acid/base equilibrium.

Stability constants of complexes

I don’t claim to be a chemist by any means and normal marketing lingo doesn’t sell me like most folks. But for me the proof was in the pudding… When I tested with my water I was amazed – like I said no more pH daily testing for me. Granted I need a bit higher EC to maintain the stability, but once it’s reached I rarely have to use pH up or down, at most once a week for fine tuning. Considering how wild my well water can be this has helped me a lot. I literally have a shelf full of every nutrient line on the market but haven’t touched any of them since I found Ionic.

@anon32470837

Well, thanks to an unfortunate equipment failure - one of my solenoids stuck OPEN

Ouch. Are these NC solenoids? Was it a timer issue that sent constant power? (Just thinking this failure through to see how I can prevent this type of thing in my own system.)

@anon32470837

Wow! I guess PH really is important!

By far one of the most important things in hydro, for sure.

It’s amazing how quickly things can recover in these aero systems, isn’t it? Unfortunately that also means failures can do bad things just as fast.

[anon32470837]

@SuperiorBuds

I don’t claim to be a chemist by any means and normal marketing lingo doesn’t sell me like most folks. But for me the proof was in the pudding…

Thats well beyond my 40 year old, chem 101 knowledge too! I was reading about other brands of nute that also say they are PH stable, so thats a real thing I guess.

The problem, as you say, is in the EC you need to run to keep things stable. From what Atomizer said, if you are spraying enough volume of nutes to recirculate, then higher EC is no problem, but at very low flow rates, the droplets can evaporate enough to multiply the concentration in the droplets.

If a 50 micron droplet evaporates 1/2 its volume in the time it takes to get from the nozzle to the roots, then the EC will be double. Smaller droplets will loose volume to evaporation faster than larger ones, so some droplets may triple in EC as they evaporate. He recomends running at 1/4 to 1/2 normal EC levels if you have low enough flow rates and small enough droplets.

I am seeing some evidence of that in my system. The inlet PPM probe always runs a little lower than the outlet probe - even though there is essentially no plant action going on to this point. How much seems to vary from day to day, so Im assuming that the relative humidity and temperature around the root chamber are factors. The only thing that I can imagine causing that is evaporation of the droplets after they leave the nozzles and before the water gets to the collection chamber.

Im running an EC in the rez of about .5 and the runoff has been just slightly above that. So far the difference has not been more than 10% at the most though. That would have to be an average, so Im thinking that smaller droplets are going up a lot more in EC than the larger droplets. The big ones are probably not changing all that much, while the smaller ones are changing a lot more.

@SuperiorBuds

Ouch. Are these NC solenoids? Was it a timer issue that sent constant power? (Just thinking this failure through to see how I can prevent this type of thing in my own system.)

Im using the same Normally Closed solenoids you are. It was a mechanical failure of some kind. All the solenoids are driven by the same timer, with separate solenoids for each nozzle. Only the one nozzle that failed stayed open, and it stayed open with the power shut down completely.

@SuperiorBuds

It’s amazing how quickly things can recover in these aero systems, isn’t it? Unfortunately that also means failures can do bad things just as fast.

I am constantly surprised by these plants. Thats one of the things I Like about this growing stuff

I think Im finally getting close to dialing things in enough to start relaxing - unless I just jinxed it!. Im currently running at .3 sec ON and 33 sec OFF and everyone seems happy.

Ive been playing between .3 and 1.0 seconds ON and 30 to 120 seconds off. One of the tricks is that if you let things dry out even a little too much, you have to go heavy for them to recover. Then you have to start over dialing it back down slooooowly.

I really should have gone with just seeds or just new clones. They seem to want different wetness levels, so Im kind of balancing things in between for now. It may be another week before the clone starts to show roots.

[anon32470837]

I am continually surprised by things that are happening. Thats interesting, but sometimes leaves me wondering what the heck is going on?

The not so good and slightly confusing first. My rez water continues to go up on the PH even with no circulation. I just checked and the rez is at 5.4, the accumulator tank is at 5.3. It just topped off, so it was probably a little lower than that before the top off. The runoff is at 6.3! grrrrrrr

Im going to try again with the rez starting at 4.8 and check it more often.

One good surprise - I have fuzzy roots!!!

Not a lot and not very big and not on all the roots, but there are fuzzies!!

The interesting, confusing, and disappointing thing is that the seedling is still not growing as fast as the others in the cups, and the roots are branching like crazy, and getting fuzzy, but not getting longer. Seems odd to me.

[ReikoX]

@anon32470837

The interesting, confusing, and disappointing thing is that the seedling is still not growing as fast as the others in the cups, and the roots are branching like crazy, and getting fuzzy, but not getting longer. Seems odd to me.

Could it be air pruning the root apical meristem? Same thing as topping a plant, or what fabric pots do.

[anon32470837]

GMTA! I was just looking closely at the pics, and the original single root hair (the one with all the branches now) does look slightly brown on the very end in some of the shots. It only shows up in the pics, you cant tell by looking at it. You can see some of the browning in the first pic on the main root that has no hairs.

I have read the air pruning does cause the roots to branch like that, so I think you are spot on!

I suspect I am spending too much time looking at the roots out of the chamber with no mist, and they are drying out.

[anon32470837]

Ok, Ive decided its not working very well having a fresh cut clone and a new seedling running at the same time. The clone really wants it wetter than the seedling, so Ive decided to try a different experiment.

I removed the seedling from the chamber and stuck it in a glass of water. I want to see if the roots keep the fine hairs or if they revert to smooth roots.

In its place, I put a second Blue Dream cutting that I took at the same time as the first one, but it has been just sitting in a glass of water in the tent this whole time. I re-cut the stem and added a dash of fresh rooting hormones, and stuck it in the puck and turned up the cycle to .5 on / 55 off.

I also decided to take a close look at the roots of the other seedlings I started the day after the one thats been in the chamber. I wanted to see how different the roots looked growing in small perlite hempy buckets vrs the ones in the chamber.

Turns out there is a big difference.

The ones in the perlite are much longer, and have more branches, but are mostly smooth. There are some very small fine hairs and a couple of small places where the roots are webbed sort of, but not the same small hairs.

Here are some shots of both sets of roots.

First - the ones that have been in the HPA chamber. There no huge change from yesterday.

Now the two that have been in dixie cups started a day later.

There is definitely more total root mass in the dixie cup ones, but Im not sure how to interpret that. All of them looked healthy. The one in the chamber was growing slower initially, but had started to catch up the last day or so. - after I got the PH into a better range.

So… Ive decided to do a second phase to the root test. The original HPA seedling is now sitting in a glass of water. We will see if it looses its fine hairs or not.

For part two of the test, I took one of the seedlings from the perlite, and stuck it in the same puck with the #2 clone cutting. We will see if this one develops new fine hairs now that its in the HPA chamber.

[anon32470837]

I think I have my PH issues more or less under control now. If I PH the rez down to 4.7-4.8, and then immediately top off the accumulator tank right away, the tank keeps the PH fairly close. It went from 4.7-4.8 yesterday to 4.9 today. The rez went up to 5.8 after 6 hours, but I PH’ed it back down to 4.8 and its now holding at 4.9 after an additional 10 hours.

The runoff in the chamber is at 5.8, so thats perfect.

This will work, but its still a pain. If Im going to run D2W, and at low EC levels, I dont think I have any other choice though. It would be ideal to DIY an auto doser, but thats not in the budget.

[SuperiorBuds]

@anon32470837

The problem, as you say, is in the EC you need to run to keep things stable. From what Atomizer said, if you are spraying enough volume of nutes to recirculate, then higher EC is no problem, but at very low flow rates, the droplets can evaporate enough to multiply the concentration in the droplets.

That’s interesting and something I hadn’t thought about. I am hoping to do a lot more testing before I start the next run, I’ll probably ping you for some thoughts when that comes up.

@anon32470837

Im using the same Normally Closed solenoids you are. It was a mechanical failure of some kind. All the solenoids are driven by the same timer, with separate solenoids for each nozzle. Only the one nozzle that failed stayed open, and it stayed open with the power shut down completely.

Ouch, yeah hopefully that was just a fluke. I’d hate to see what would happen if one of mine stuck open haha.

@anon32470837

One good surprise - I have fuzzy roots!!!

Success! Looks good!

@anon32470837

I suspect I am spending too much time looking at the roots out of the chamber with no mist, and they are drying out.

I bet this is part of my problem right now, as well. My lids aren’t secured all the way down and I notice there’s some airflow getting to the roots. (I see mist coming out the tops.) The refactoring of the system will solve this for me, hopefully I can get better results once I nail that down.

[anon32470837]

@SuperiorBuds Do you have an easy way to test the PH from separate parts of your system? Im curious to know if the PH of your nutes performs the same way mine does, and goes up when it gets sprayed.

[SuperiorBuds]

@anon32470837

@SuperiorBuds Do you have an easy way to test the PH from separate parts of your system? Im curious to know if the PH of your nutes performs the same way mine does, and goes up when it gets sprayed.

Hm, I should be able to test each part. I have a bypass valve that I can flip to pull some water from the accumulator so that part is easy.

For the nozzle spray I’d have to do your plastic bag capture trick I think. Not sure there’s any other way to measure my mist pH – any thoughts on that? (Will recapturing the mist throw off the measurements?)

I can test those out tonight once lights come on. I’ll be spending quite a bit of time in the room tonight anyways – harvest is any day now.

[anon32470837]

The last few days, I have just been putting a Tupperware container in the bottom of the root chamber and testing that. I get enough to test in a couple of hours.

The bag idea should work too, unless you have some way to tap into the return before it gets to your rez.

[SuperiorBuds]

I can pull runoff from the return but the problem there is that the E&F water is mixed there so I think that’d throw off the experiment. I’ll try the tupperware method, that should work for me. It’ll be interesting to see if I get the pH changes, too.

[anon32470837]

This morning my accumulator tank is holding at 5.0 and the runoff is at 5.8. Rez is still about 4.9.

I checked the first clone for root hairs this morning. Its been in there for 5 days now and some very small hairs are showing up. Thats about two days faster than with the LPA setup, plus I have hairs where I scraped and where I didnt - for what ever that is worth.

.

[anon32470837]

Its starting to look like HPA does produce different - fuzzy - roots when compared to regular hydro.

The seedling I started in the HPA chamber had nice fuzzy roots two days ago when I pulled it out and put it into a glass with PH’ed water and light nutes. Most of the fuzzy hairs are gone!!!

Here is a pic from 2 days ago.

Here it is today. Lots of new root growth, but its all smooth and most of the original fine hairs are gone.

The one that started in the dixie cup, with smooth roots, but has been in the HPA chamber for two days, now has some fuzzy roots starting to show up.

On the subject of preparing cut stems for cloning - it sure looks to me like scraping the stem is the wrong thing to do. Im seeing far more fine root hairs showing up in places where I did NOT scrape the stem. In places where I scraped it hard, there are zero root hairs. There are some in places where I lightly scraped it, but far far more where I didnt scrape at all.

So, no more stem scraping for me.

[anon32470837]

Well crap. A second solenoid has failed OPEN!!

After looking for reasons why, I noticed the solenoid is only rated to 0.8MPA or 116 PSI max. I have been running it at just over 120. To make things worse, when I have the pressure reducer set to over 120 PSI, it allows excess pressure to bleed through from the accumulator tank, so the valves have actually been seeing 145 PSI between pulses.

So, Ive replaced the bad one with the spare and turned down the reducer to 110 PSI. The bleed through pressure is about 115 now.

Im going to have to keep my fingers crossed, and keep a spare or to around at all times, because I cant find any plastic solenoids with a higher pressure rating.

Im going to have to search for better nozzles that will atomize properly at lower pressures too.

I may try adding some higher pressure anti-drip valves to these if I cant find any better ones. Im hoping that if there is less pressure differential across the solenoid that they may last longer. Right now, the anti-drip valves in these nozzles open at 20 PSI. That meant that when the valves closed, it left 20 PSI on the nozzle side of the solenoid. So, 140 - 20 = 120 PSI differential across the solenoid. If I can find some that open at 50 or 80 PSI, the differential pressure will go down accordingly. That should be easier on the valves.