Another second thought - you’re right about the tap water and probable extra CO2 from pressure in the system. I did not give it time to stabilize. However, the rez water has been in the rez for several days, so Im sure it has had time to equalize the partial pressures of CO2 and O2. Yet tap water and rez water both go up in PH when shaken - the rez water more so. In those shaking tests, there is no abrupt temperature change or pressure change, and I dont see how shaking would change the alkalinity, so Im still mystified.
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You are THE MAN!!!
From that video, its the turbulence from the bubbles thats causing the CO2 to leave the solution. That would be the same effect when shaking the water and especially when spraying the water. The shear forces that break the water down into small droplets have to be many times as strong as simple bubbling.
So, in my original HPA rez, I was running the pump far more often and for longer times than I am now. I also had it set up to flume much more strongly. That frequent fluming, plus maybe the algae that was growing, could easily have been why the HPA rez would increase PH.
Then when it got sprayed, the shear forces, and probably the sudden increase in surface area when the droplets get formed, would drive the PH up even more.
With the new AAA rez, Im doing very little stirring/fluming at all - one minute every 8 hours vrs the old system at 15 minutes every hour or so. Im guessing the new setup might be raising the PH slightly when the pump runs, but then the water has 8 hours to re-equlaize the CO2 in solution.
Both HPA and AAA nozzles will cause vastly more ‘turbulence’ and aeration as the droplets get formed than a simple air stone.
Ok, so that explains whats happening - but - I still have questions.
- Does this really matter? Or to put it another way - am I worrying about a phantom problem? Is the PH rising as the water leaves the nozzles really causing the plants any distress? Or is the water still within range as far as PH by the time the water gets to the roots?
It seems to me that every single HPA and AAA setup that uses hi pressure water or air to atomize water would have the same exact problem of the PH rising. I would also expect LPA systems to have the same problem of a climbing PH. Especially in re-circulating systems, but maybe to a lessor degree.
Its common for recirculating systems to have PH issues, but its hard to know what the exact cause is in many situations. It really makes me wonder though.
I would expect ALL HPA and AA setups to have the same problem, especially if they are recirculating, but no one has called it out that I have seen.
From that video it looks like a slow process, but I bet that micron sized droplets would react much faster than a larger water volume.
It would be helpful if I could test the PH of the water as soon as it leaves the nozzles, but it takes hours to collect enough volume to read with my PH meter.
So far my only idea is wait to see if the plant tells me its having issues related to PH and adjust accordingly. In the HPA grow I did try lowering the PH in the rez to adjust for the PH changes, but that didnt go well. I may have over corrected, but I just don tknow.
In any case, thanks again for finding that video. Its a big relief to finally have a theory for whats happening that makes sense AND fits all the data and observations!!
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I decided to try something as far as testing the spray PH. I have some pool/spa water test strips that check alkalinity, PH, chlorine. I got them to test chlorine, but they dont work for crap doing that. I decided it wouldnt hurt to try the PH test and see what happens.
Unfortunately, they only go from 6.2 up to 8.4. When I check the rez, which is still at 5.8, they show the lightest color which is 6.2.
So I tried several of them by holding them in the spray coming from the nozzle at different distances. They all read the same - the minimum of 6.2.
Then I put one in the runoff water (which takes several hours to accumulate) and it immediately turned darker and indicated the PH was around 6.8 - which is close to the 6.7 I measured with my meter.
So…if these strips are reading correctly… it looks like the water is not changing PH instantly after leaving the nozzle. After maybe 3 minutes, the strip is noticeably darker, but stil not as dark as the test from the runoff.
If thats what is really going on, and not an artifact of defective test strips, then thats good news. It means that the roots are not getting blasted by hi PH water. The roots that eventually make it to the bottom of the root chamber may have issues, but that is only going to affect a small portion of the total root mass. I am more hopeful now.
The top strip is from the rez. The middle ones are all from various distances away from the nozzles. The bottom strip is from the runoff water.
On the bad side - Ive been loosing root hairs since yesterday. I have been forgetting to keep my bottle of LITFA handy, and so I have been unable to resist the temptaion to mess with timing. Im going back to my original 0.3/30 and see if they come back.
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Its been one week today I put the seedlings into the root chamber. The roots are getting some fuzzies back, but not like I would like to see. They are also growing more down than sideways. There is some lateral branching, but not as much as last grow. This time Im seeing one single main root that has laterals. Last time, the main stem branched into several different stems and each of them had laterals as well.
So - I think I have been running too short an ON time and not enough off time. Im trying 0.4/40 at the moment with positive results so far. I may up the off time more in the morning depending on how things look.
The plants look ok up top. The larger of the two is developing some oddly malformed second set of leaves. The runt in the mean time is catching up in size and looks better formed and a bit happier.
The big boy
The runt.
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Time for some notes on whats working and whats not.
The ice chest is working great as far as keeping the nutes cool. I can put a single 16oz frozen water bottle in and it keeps the temps below 68F for a full day or more. It will initially drop down to 63-64 and slowly climbs back to 68F. Thats when I add another bottle. If I do 32 oz frozen bottle it lasts almost two days. So far, its been relatively cool in my grow room this year. It has not gotten over 80 yet, but Ive been doing creative things with fans and open windows.
On the bad side, I noticed a nasty smell in the rez yesterday. A real rotten smell which makes me think it was some kind of nasty bacteria. I think maybe the rez was a little too well sealed up and not getting enough O2. So, I drained, and cleaned it with pool shock. When I refilled it I added some more shock so its a steril rez for the moment. I also rigged up a stop which hold the lid open a tiny amount - to allow some more air circulation.
I had been running the circulation pump one minute every 8 hours, but I changed that to 1 minute every hour. At the 1min/8hr setting, I was seeing no rise in PH over time. Its been about 16 hours with the pump running 1min/1hr, and the PH rose from 5.7 to 6.0. So Im going to increase the off time on the pump until it takes at least a day or two to climb that hi and see how it goes.
Hopefully, the increased circulation/aeration will keep the nasty crap from growing. I really dont want to do sterile if I can avoid it, but I may have no choice.
The plants look pretty good to me as far as color and growth, but one of them still looks to have an oddly formed second set of leaves. That could just be genetics.
The nozzles, solenoids and water, and air feed systems all seem to be working perfectly from a mechanical stand point.
The roots are still giving me some trouble though. Ive lost all fuzzy hairs twice and even gotten some browning on some of the roots. I am assuming its from what ever was smelling up my rez, but the mist timing may still need dialing in.
On timing - Im having second thoughts on my idea for using very short ON times. That doesnt seem to be working very well, so Im back to “filling the rez” and using a longer off time = 0.6/45 for now. Too soon to tell how thats going.
The main problem is - its really hard to tell if the root issues are from bad timing or root rot or PH issues or feed issues or or or or something else Im not aware of.
There still isnt a lot of root mass, so that also makes it more difficult to see whats happening. On the other hand, its only been one week, so I may be expecting too much for this early a trial. More dialing in required…
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Well poop and other bad words… Ive had a rough few days with kidney stones, got really stoned, and messed with timing (while stoned) when I should have been using more LITFA. At the same time, I used too much LITFA on my rez and it went bad again. Somewhere in there I forgot to turn the timers back ON after changing the position of the nozzles. For a little over 12 hours. Surprisingly, the plants did not die, but the roots look like crap and are all shriveled up and brown.
On top of that, I smelled the rez again this morning and its gone bad again - even with the extra stirring and air circulation.
So, Im gonna toss these babies, and CLEAN the rez much better. I am sure I could nurse them back, but I dont want to spend the time doing that. What I need to be doing is to keep playing with fine tuning the mist cycles to get good fuzzy hairs, and I cant do that with mostly dead roots. The nasty crap in the rez just adds to the problems. Im starting to think I have no choice but to try a sterile rez. My main reluctance on that is the bleach tends to kill fuzzy hairs…
Ive decided to try some of @ReikoX autos for my next grow. He has one strain that is good for sleep and pain that Im going to try. Im hoping the faster grow times will help me get an extra grow cycle in this winter. My last C99 grow took almost 17 weeks from seed. Finishing up a grow in 8-9 weeks will be nice. Im hoping my yield/day will be close to what I have been getting on the longer, photo period grows.
Ive figured out how to get my root chamber centered in the grow tent. Its been sitting off to one side because I have a large carbon filter under the table thats in the way. With the much simpler (lower parts count) AAA setup, I now have more room on top of the work bench, so I can slide the tent over to center it in the chamber. That will make it much easier to ‘fill the tent’ with a few fast growing autos. Im thinking I will start with at least two and possibly three plants.
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I seriously think this is where you should start. I know we went around and around last time trying to solve this which has resulted in you running the air pump at intervals, but that seems very counterintuitive to me. In every single hydro setup I’ve ever ran I have always ran the air pump 24/7 – that is how I prevent algae growth. The only time I’ve had stuff growing in my res was when I wasn’t pushing enough air through, resulting in stagnant areas in the res. I know you were focused on the ph rise with additional air, but I think that’s a separate problem to solve and by running the air pump on a timer you’re actually creating a new problem.
I’ve had the same res water in my tank for 3 months now, I pull a gallon or so a day to water the tent, but otherwise it sits there boiling away. Look at this video of mine and you can see how much turbulence the air pump introduces to the water.
Bubbling Water
https://www.instagram.com/p/BzBWOYWgviP/
I think I’d like to revisit the ph-rise problem with you.
Did you ever try RO water?
What are you using for a reservoir?
What nutes are you running these days?
Any beneficials?
What size air pump? Are you using one w/ a remote inlet? Any filters?
You talked about light in the res, but I’ve never really worried about that, as long as the water movement is enough to prevent any growth. (I once had an open res in the grow room, directly under the lights – nothing growing in there.)
Perhaps it’s time to check out the Torus Hydro pH perfect.
https://www.torushydro.com/products/
I’m running the 70 gallon version in my 35 gallon res and I haven’t adjusted pH once since I dropped it in. (Months and months ago.) Keep in mind my RO water comes out at a super-high pH and is auto-added via a float valve to keep water levels at max.
I remember the original problem and all of the things we did before to try and solve it – but I feel like this water issue you have has to be front and center. Otherwise you’re just kicking the can.
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Sorry for the slow reply - Im still not 100%over the stones, and now super busy.
Ive been thinking along similar lines - the rez crap needs to get handled. How to do it is the question.
Im not convinced your theory on aeration is the answer - at least as far as the algae. I agree that would eliminate the anaerobic bacteria/smelly rez problem though.
But - some simple experiments should answer that easily enough.
That PH filter is a cool find!! It looks like its using the ionic resins we discussed last year. I like that they offer the solution to re-fresh the resin after using it for a while.
So - you have one? What PH does it lock onto? I doubt I will go that route - too $$. I do still have some of the MES buffer. That did work to stabilize the PH, but again, its an expensive option.
Part of the problem with the smelly rez may be due to old dead crap buildup in the pump. Im doing a much more thorough cleaning now. Then I will do some more experimenting with aeration/PH control and see where that goes.
Thanks!!!
Oh - I did try the RO thing, but it made no difference at all that I could tell.
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Ok, Im ready to get back to it. The rez is a plastic ice chest. It and the pump, tubing, solenoids, etc, have been soaking in strong bleach for several days.
By the way, Im not using an air pump this time and didnt last time - just a 300 GPH circulating pump sitting in the rez.
Two grows ago, I did super aeration = 6 air stones in a 17 gal black tote, driven by a 700 GPH air pump, PLUS, the same 300 GPH aquarium pump driving two constant water falls in the rez, PLUS the grow chamber was LPA, so constant spraying, with a strong NFT component. PLUS the return water water fall back into the rez.
In other words, you couldnt possibly get any more air into the water unless you over pressured the rez to increase the partial pressure.
With all that I still had algae growing and had major PH control issues. I did NOT have any bad smells though. The smelly part is new.
I like the idea of more aeration. Normally I would highly recommend doing as much as is reasonable to get close to 100% DO. However, in the case of HPA or AA, the aeration isnt really necessary. The mechanical process of breaking down the water into 50 micron droplets does all the aeration you could possibly want as far as the roots are concerned.
BUT - of course you cant have a stagnant source of water that has nutes and air born bacteria or you will end up with anaerobic bacteria and bad smells.
The rock vrs hard place Im up against is the PH rising issue. It sure looks like if I aerate enough to keep the rez smelling good, I get wild PH rises.
From my reading, it looks to me like this is going to happen no matter how much PH down I add. If I am understanding the process correctly, adding PH down increases the dissolved C02 - in the form of carbonic acid.
The problem is, carbonic acid is just dissolved C02. I think this is because of my waters alkalinity, but that extra dissolved C02 (created when you add PH down) is greater than the C02 equilibrium level in my water. That means it will out gas over time until the C02 in the water is in balance with the C02 in the air. That out gassing drives the PH up because there is less carbonic acid in the water. My waters natural PH is close to 7, and thats where it wants to go back to when the C02 out gasses. Strong aeration just speeds the process up.
Also, no matter how much PH down you add, aeration drives the PH up all over again until the C02 is again in balance.
Using RO water made no difference in the PH rise, but I was able to stabilize the PH by adding the MES buffer. It didnt stop it, but it slowed down the process enough for it to take two or three days for the PH to rise instead of a few hours, so it was manageable.
Im not wild about using the MES buffer. Its more a cost issue. That stuff is $$. Same deal with the super cool resin filter you found. I like that idea much better than the MES, but its even more $$$.
At least thats the theory as I understand it.
So, Im going to try a new test with fresh, clean tap water in the newly clean rez, plus my usual level of Mega Crop which is in the EC 0.4 to 0.6 range for aero stuff.
Im going to let the rez water stabilize as far as temp and C02 over 24 hours with the pump running intermittently. Then Im going to adjust PH and kick the aeration up to max and see what happens and how things react to adjustments, etc.
Any suggestions for tests, procedures, etc welcome.
These are the babies Im going to try next in the chamber of death 
Thanks to @ReikoX for the auto seeds!!!
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I soaked the seeds for about 24 hours, and now they are in paper towels in a dark warm place.
REZ news…
So, I mixed up a new rez at EC 0.3 and PHed it down to 5.8. I had the rez running constantly on hi aeration = 300 GPH pump running 3 minutes ON and 1 minute OFF fluming constantly.
I also pulled out a sample from the rez after adjusting it down the first time and set that aside so it could just sit still, but open to the air.
The small sample went up to 6.2 PH but it took about 8-10 hours and has stayed there.
The rez climbed to 6.7 within 2 hours. So, I PHed it down again to 5.6. Within 2 hours it was back up to 6.1. After about 4 hours it was 6.2 and holding - the same as the sample.
I repeated that process several tiimes with the same result. The rez quickly goes back to 6.1 - 6.2 PH when it is constantly aerated. It seems to take aprox 2 to 3 hours to stabilize at the current temp and aeration level.
The undisturbed sample goes to that same value, but it takes 4 times longer.
So, it seems like my water + low level nutes just wants to be at 6.2 PH no matter what I do. Aerating it just makes it get there faster.
There are a few different ways to handle this.
-
Dont stir the rez. If it just sits still, all sealed up, then there is little to no PH drift. Unfortunately, that can lead to stagnant rez water and anaerobic bacterial growth = root rot.
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stir the rez just enough to keep it mixed but run a sterile rez to keep the bacteria down. Im not wild about this option because the chlorine kills fuzzy root hairs.
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Aerate the rez to the max - but - that will require constant monitoring and adjustment of PH. This is going to need to happen at least every 4 hours. I am not wild about having to add huge amounts of PH down to my system. Thats a whole lot of extra phosphorus or sulfur depending on which PH down I use. Plus, I cant always be here to make adjustments every 4 hours. That means an expensive automated system. I can do that for under $200, but I dont have an extra $200 at the moment.
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Try to balance the aeration so its enough to keep the rez fresh, but only raises the PH slowly. If I could keep it down to maybe 2 or three days to go from 5.5 to 6.1, I would be happy, but I doubt that would be enough aeration to keep the rez fresh.
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Use MES buffer to slow down the PH rise while doing more aeration. I may be able to use smaller amounts of the MES so that the PH rises at a reasonable rate while Im doing enough aeration to keep the rez fresh. I suspect this is what Im going to end up doing. I need to go back and look at my notes on the last run where I used MES. I need to run the numbers on cost over the length of the grow.
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@ReikoX autos are coming along nicely. I started soaking them 4 days ago, and they have been in the mini hempy cups for three days. They will be tall enough to go into the root chamber in another few days.
Turns out I have an easy way to increase the humidity for the seedlings - just set them near the net pot holes in the root chamber, cover with plastic, and run the nozzles. Instant humidity.
If all goes well, these should be ready to harvest by the 3rd or 4th week in Oct. Thats 9 weeks vrs the 5 months for my last grow. Awesome time savings! If the yield is even close to my last two grows as far as grams/day, I will be switching to autos for all grows.
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Excited to see how these do for you.
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Me too!
My first grow in soil netted me around 4.5 gms dry per day counting from from sprout to harvest.
My last two hydro grows netted me an average of just over 7 gms dry per day. Hydro works much better for me.
So, if these babies do the same over 9 weeks, that would work out to 441 total grams dry. Between three plants, that would be in the range of 147 gms per plant.
If they yield closer to the soil grow levels, that would be 283 gms total or about 95 gms per plant.
@ReikoX - what is a reasonable expectation for these plants? I seem to remember reading that autos generally yield much lower on a per plant basis - like well under 100 gms/plant?
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Its very tough to say what these will yield, but I would expect around 100 grams per plant in your system.
I’m still waiting on a few running this cross to harvest (Ghost Toof x SBR), but @toastyjakes and @Mr.Sparkle both have some decent sized plants growing.
The Ghost Toof both came in around 30 grams using 1 liter containers.
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I just realized you sent two different crosses. I happened to sprout the Ghost Toof #2 x SBR.
So, if three plants yield 100 gms dry, thats 300 grams over 9 weeks which is 4.7 gm/day yield. Thats slightly better than the 4.5 gm/day I had in soil, but a good bit less than the 7+ Ive been getting in hydro.
If I went with 4 plants that would up the yield to 6.3 gm/day, which would be plenty with this fast a turn around.
I might be able to do 4 plants just fine, but will have to wait and see how this goes first. Im worried about root crowding, but we wont know until I actually try it.
I think its going to depend on how well they respond to my scrog training and if I can keep the roots happy.
They seem to be developing just fine s far. Five days since they popped. Another day or two and they will be tall enough to transplant into the system.
Im running these with a 20/4 light schedule at low wattage so far.
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@shroomgod - is that the same strain? Was that after harvest or part way through or? Im wondering what kind/size of root mass I will end up with.
I decided to start the autos in the system. Its interesting to see the differences in root structure at this early stage. Im curious to see if this continues as they grow.
Im starting off with an EC of 0.4, PH=5.7 at the moment - subject to change…
Timing is 0.7 sec ON / 30 sec OFF. I’ll look at the roots in an hour or so and see how wet things look.
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This is such unknown territory. I cant wait to see how these turn out. Dont think I’ve ever seen an auto run in an aero setup.
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