PH drift making my coco DTW a PITA...jacks +

Indoor Growing
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Hey everyone hope all mostly well for you all around the globe!

Before I get home from vacation and am planning on cleaning up the space before starting some more beans I wouldn’t mind figuring this out.

So as the title suggests I have been doing coco DTW for a couple years now. I dont have any grow shop less than an hour away and use canna coco bags.

I have been having great success with a combination of Jacks Hydro… not 321 but a custom ratio I found someone sharing a while back with an even ratio of Jacks and Cal-Nitrate with added sulfur in veg (cant remember exact salt… doh… as Im not home also wont be able to look for a week+), and silica added as well. No epsom, but after seeing another thread here searching for the perfect jacks or similar ratios I may again be switching things up…

Other than these I have been using Seagreen as well at close to 1 ml per gallon in the rez (maybe this is my prob?) and MAP for bloom boosting starting in week 3 usually…

I use a 30 gallon garbage can as a rez usually and typically have to PH down every single morning with 24 hours later (next morning) the PH drifting back from 5.8-6.3 depending on how far in flower I am up to 7.5+ as far as I remember… this doesn’t make leaving the house for a weekend very easy knowing that I either need someone to give me a hand or bw there to adjust the PH every morning again.

Other than buying an automatic PH adjusting system any thoughts? Does this happen to people using Jacks, but not Seagreen?

Oh and I usually leave a pump on in the rez keeping it mixed and circulating 24/7 as well.

Thanks for any insight

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Is this something new or has it been since the beginning?

I dont know about Seagreen - is it something organic?

I am running aero DTW. My water has some sort of algae/bacteria in it that love any nute with organic components. When they (algae/bacteria) get established, the PH rises constantly. I had your exact issue when I was using Fox Farm, Advanced Nutes PH Perfect, and Mega Crop.

After I switched to Jacks 321 hydro, the PH became much more stable.

Its also possible you have a hardness issue with the water. If so, any aeration will drive the PH up - no matter how often you PH it down. Its a dissolved C02 issue

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@anon32470837 Primordial solutions Seagreen is an organic compound pretty sure and I think it also has beneficial and maybe humic or folvic though I need to confirm… will look up the label. Supposed to help chelate or make the nutrients more available and easy to use by the plants as well. I have been using it mostly the whole time and I think my old PH meter may have been funked up and not working correctly and I wasnt noticing these large swings.

Would not be surprised if this is the culprit although I do love using it.

I am pretty sure Capulator the creator of OGBiowar swears by using it and he, as far as I remember, was also running Jacks and Coco DTW.

I use OG Biowar as well, but when I apply it I am either foliar feeding or mixing up an individual batch in a 5 gallon bucket for the final watering of the night when using it as a soil drench.

As far as I know the majority of the time the tap water where I live is essentially untreated, unless they are cleaning the system out in which case they usually alert us that the water is being chlorinated and that it will pass in a day or you can run it out of the system pretty rapidly.

Last time I checked I was hitting around 170ppm for the tap as well. I dont own an Reverse Osmosis system.

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Also currently using Jacks. Previously used GH and Megacrop.

Using RO water and Jacks, my PH has never been more stable.

For example…Set at 6.0…will slowly creep up to 6.2 after 4 days.
Works for my coco since I like to vary the feed ph from 5.8 thru 6.3.

I might try…
A Mix without seagreen. Stable?
A Mix with RO water, no seagreen. Stable?

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I can try without seagreen but I do not own an RO machine though. If doesn’t work must be something else in the water i guess… do you guys keep your mixed solutions agitated with a pump as well?

Thanks for the thoughts. Also curious if anyone else on here uses Seagreen.

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Silica will cause your pH to drift. For DTW, I’d recommend taking it out if you can’t keep up with the adjustments.

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@lefthandseeds Was not aware of this. Thanks

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Yeah 99% sure that’s gonna be your culprit. I go back and forth on it, because it’s tough to keep up with. Take it and and you’ll probably see your pH holding much better.

It is nice to have though… but it’s not completely necessary. Sometimes I’ll feed it for veg only, and it is good enough.

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I don’t, personally. I tried it a few times, and didn’t find any benefit. In my recirculating systems, I do have the return hose or pipe let out above the rez water line, which does serve to perform some aeration as it pours back in and agitates the surface, but I’m pretty confident it’s not necessary.

I was going to suggest the same thing. I like silica, but it’s more work than I’d like trying to keep up with it.

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Redundant information thats always a plus, much thanks! Not that I didnt believe you @lefthandseeds :+1:

Will be trying first to not use silica and if that doesn’t help will then try without silica or seagreen…
If that still doesnt work I will try to get my hands on some RO water and see if maybe my water is the culprit.

About bedtime over here… thanks again for all replies

Edit: also may turn off circulation pump to boot

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Sounds like the right plan, in my opinion.

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This is my current mix.

If I don’t add the silica up front, I end up needing almost the same amount of PH-up to set at 5.8.
That mix gives me 5.8. Zero adjustments.

I have a tiny pump that recircs and waterfalls, 24/7.

RO unit I’m using.

EDIT: In addition to the above, I’m using.
Orca .5ml per gallon
Floralicious Plus .5ml per cal

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Running my water through an RO filter did me zero good. I still had drastic PH increases when using anything organic in the rez.

Every ones water is different as far as calcium hardness, and as fas as I can tell, an RO filter doesnt change hardness either, so I dont see any benifit to going RO as far as PH concerns.

My water comes out of the tap around EC 100 or under, so you cant tell by EC alone.

I still have a circulating pump in my rez which runs 1 minute every 30 minutes. I like to keep the rez at least a little aerated to make sure anaerobic bacteria cant get started. I worry that leaving nutrient rich water sitting in the dark for days on end, with no circulation, could be a breeding ground.

I live in the Pacific North West, pretty much in a rain forest. My soil outside is mostly decaying pine cones and needles. It rains a ton, so its constantly wet and not that sunny much of th time. Perfect breeding ground for all sorts of molds, bacteria, algae, etc etc. Im also on a well, so I know my water has that stuff in it out of the tap. Plus its in the air.

My water comes out of the tap at 6.7-7.4. The alkalinity in the water means that I can PH it down to 5.8, and it will slooooowly climb right back to 6.7 over anywhere from one to 3 or 4 days. If I aerate it, the climb is faster. Strong aeration can make it go back up in just a few hours. This is with NO nutes in it at all. PH it down again, aerate it again, and the PH goes back up. With calcium hardness, its not possible to keep it down. The cycle just repeats over and over.

Some people have this problem and some dont. It will depend on the alkalinity of your water.

Treatment or no treatment has nothing to do with this cycle.

The bacteria/algae is a completely separate thing that can be going on at the same time - or not. I have both issues, you may only have one or both.

You cant change (lower) the alkalinity unless you buy bottled water as far as I know. So you are stuck with that problem - if you have it.

The organics is a different story, If you have bacteria/algae similar to whats in my water, then you will probably need to eliminate ALL organics.

For me, the organics/bacteria/algae cycle was the biggest part of the PH rise problem. The hardness/aeration rise is much milder and actually works for me now. The Jacks tends to hold PH fairly well, so my aerating the rez with the circulating pump makes the PH slowly drift up. I PH down to 5.7 usually, and it will drift back up to 6.1-6.3 over 3 to 5 days depending on how strong I mix up the Jacks. At low EC levels, the PH rise is much faster, and at hi EC levels its slow.

I agree with Howard and lefthandseeds - take out the organic silica and see what happens. I would go further and take out ALL organics and see how it does.

You can test the alkalinity thing by just taking some tap water (no nutes), and PH it down. Then either just let it sit or better yet, aerate it and watch to see what the pH does. If it goes back up, you know you have that problem. If it stays stable, your are good.

Edit: I screwed up and said it was calcium “hardness” that causes the PH rise - its actually alkalinity and calcium carbonates in the water. I will change the above text.

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Hi Larry, just a side note. An RO membrane should significantly reduce the hardness in the permeate (calcium/magnesium salts). The resulting permeate should have an exceedingly low EC. If not, there’s some amiss in the RO system / damaged membrane. I’m not certain if you’re differentiating an RO pre-filter vs an RO membrane.

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I was using an RO membrane with three other pre-filters including carbon. Maybe there are better RO setups that would work better than mine, or maybe it is damaged. The EC of the water was lower than I could measure though.

Plus - I mis-typed above. Its the alkalinity that is the issue. Do good RO units lower alkalinity?

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Thanks for the table! @GramTorino

Yeah I do not add anything prior to my silica as well, mostly due to what I read about potential nutrients locking up and falling out of the solution but another good heads up.

I want to say I am using potassium silicate in salt form, mixed with a pitcher of water and then added to the rez.

@anon32470837 I am also in the pacific northwest but I don’t get a ton of rain as I am on the east side of the mountains. The water alkalinity and calcium features playing a role is interesting and I will have to give straight tap water a test and see how the PH holds without anything added.

Thanks again for all the great info.

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It would if we are talking about carbonates as the cause of the alkalinity. Alkalinity is not necessarily a bad thing as it basically can become a buffer. Although, not necessarily in the range we’d want it for hydro (e.g. the 6.3 carbonate cycle thing).

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I shouldn’t try to do chemistry. I hate chemistry. This is probably wrong, but IIRC its the calcium carbonate that is the main culprit.

When you add PH down, and you have (which ever chemical) in your water, it forms carbonic acid - which is just dissolved CO2. When you aerate or agitate the water, that dissolved Co2 leaves the water as you aerate. When the Co2 leaves, that means less carbonic acid, so the PH goes UP.

Then when you add more PH down, you get more Co2 dissolved, which forms more carbonic acid, and the cycle starts all over again.

I “think” I got that part right - maybe :slight_smile:

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Will be adding this freebie “fulvic” to my mix starting this evening.
Fingers crossed it will not upset my stable PH apple-cart, but I realize it could.

Apologies - I forgot to mention on my original post…
I’m also adding the following to every mix.
Orca .5ml per gallon
Floralicious Plus .5ml per cal
…

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Also wanted to add this was happening before, but I started using citric acid to lower my PH the last run as well.