PH dropping to low 4's within 4 days in DWC

[Thegreywizard]

So a constant struggle I seem to be having is my PH dropping down into the low 4's within 3-4 days of doing a reservoir change in my DWC.

I can't tend to my garden every day, I'm only able to go there twice a week.

I PH to 5.8-6.0, usually closer to 6.0 knowing it's going to drop rather quick over the next couple of days.

So what could be causing this in DWC?

I've read PH swing is common in DWC, but it's usually UP isn't it?

Having your PH consistently go down in DWC has to be caused from something else going on.

I plan on adding the Bluelab dosing pumps as an upgrade in late 2022. But until then I have to figure out the problem causing this now and correct it.

My nutrients:

Jacks A & B
Epsom Salt
Fulvic Acid Powder
Amino Acids Powder
Great White
Grow Genius
Enzymes
Sugaree/Sour Dee
Mammoth P (now that I'm in flower)
Budswel (now that I'm in flower)

I've been having this PH drop issue before I was adding Mammoth P Budswel, so I know it's not them. But I still wanted to list my full weekly regiment.

I'm really loving DWC and getting great results. If I can dial in exactly what's going on, I'm going to crush it!

 

[PK1]

when the water levels get low or evaporates than the nutrient level and ph get stronger. You can install a toilet fill valve and run a tap water, but then your ph will increase and your nutrient will drop because the fill valve will bring more water in. This is where you going to need a automated ph adjustment which can get costly.

you should visit your plants more often

 

[Thegreywizard]

I wish I could visit more often, but I'm only able to twice a week for the time being. Not my choice, not my spot.

I honestly don't think it's the water level dropping. I usually put around 50-60 gallons in during reservoir changes and it's not dropping that much within 3-4 days to warrant that much of a PH drop.

There has to be something else going on with my recipe

 

[PK1]

it can also be the acids that you are adding in, but i am not sure. @Dirtbag do you?

 

[Cashmeh]

So how many plants you got and how long have they been vegging. Your res size could be fine depending how many plants. I like 10 gallon per plant in flower or a little more. What kind of ph up are you using? If it's not due to small res there are other things it could be. You said 50 60 gallons and I've never heard of a Dwc that big, so is it multiple buckets, a res, you gotta pump? Little more detail on what stage your plants are in. How often you do full res changes. What's your ppms.

With all those additives it worries me too if ur just Dwc with no pump. I'd want it all mixing. Ph dropping can also be root rot or even photos of leafs can help if there are nitrogen deficiencies you could just be mixing wrong and running out of N. So many variables.. Hook us up with pics and more info plz.

Then there's the alkalinity Aqua always talks about. Hit that search bar for it.

Good luck bud

 

[jguit]

If you're running RO water, @Cashmeh 's response woulkd help. You need to get a bit of alkalinity in your water. I personally dont run DWC but adding a little bit of tap water to my RO feed water stabilizes my pH extremely well.

 

[Thegreywizard]

Thanks for the responses everyone!

So at the moment, I am unfortently using tap water. I will be using RO down the road, my it's not my place and not my choice and I can't use RO right now.

My tap water is around 300-400 ppms, which is rather high for tap water around here. Usually it's around 160ppm.

After adding everything for my recipe, I usually end up with around 1400-1600ppms.

My DWC setup allow for 8 plants with around 50-60 gallons of total water volume.

I didn't have a great start with my seeds, so only 2 plants are monsters, and I had to take clones from those to fill in the other 6 sites. 2 of them are trash while the other 4 are going to be decent. But no where near max potential for my planned setup. It's rather disappointing.

I'm using eight, 8" air discs with an EcoAir 7 commercial air pump with a custom manifold I built to feed all 8 air discs.

I also use two EcoPlus 633 Fixed Flow Pumps on either end to help with ciruclation.

I then use one of those pumps and 2 ball valves to easily drain my reservoir.

The milk crate in the middle is to give additional support to the middle of the lid so I didn't have anything break and become a disaster later in flower. The lid wasn't designed for this type of use, but it works well and the additional support in the middle is at the very least peace of mind. But also very functional without blocking the flow.

This is my regiment and the order that I add them:

Jacks A
Epsom Salt
Jacks B
Great White
Sugaree/Sour Dee
Fulvic Acid powder
Amino Acids powder
Enzymes
Mammoth P (now that I'm in flower)
Budswel (now that I'm in flower)
Grow Genius (last because it bubbles up like a sonofbitch)

So I end up with aroung 1500ppm, give or take and very close to around 6.2 - 6.4 ph.

I'm lazy and have been using GH Down and Potassium Bicarbonate for my PH up.

I do also have a quart of 85% Phosphoric Acid for PH down, but I haven't used it yet and just been lazy using GH Down lol

I'm using two, 1000w Photontek CO2 Pro's

The one on the left is at 50% and the one on the right is at 25% because that plant seemed to get very stressed from too much light.

Because I had a fucked up setup/veg, I had to veg out the 2 plants too long to try and get some clones to catch up enough to do a half-way decent run.

So normally those huge plants would be only have that size and there would be 8 of them, evenly filling out that canopy with SCROG.

This is what things look like now:

The one plant on the left is crushing it, while the one big plant on the right has been suffering from something I've been trying to dial in between lower PPMs or less light. Sadly it's no where near the production of the big one on the left.

As you can see, my canopy is not 100% full and that's very disappointing. There was a lot riding on this run and it is what it is.

But I'm still seeing amazing success with this setup overall.

I just need to dial it in and fine-tune everything so that I have a full, healthy run.

I'll be sitting very well and happy from just 8 plants in DWC. This setup should yield 4-5+ lbs easily when it's dialed in.

It's extremely easy to maintain. I have ideas for an even better & easier to maintain design, but I'll need some custom fiberglass 10' troughs. This botaincare reservoir is only 7.5' and limiting for my overall design concept of 10 plants under 2 of these large LED lights. 2 rows of 5.



So getting back to the original question, what in the hell could be dropping my PH to the low 4's within a few days?

I'm pretty sure I'm adding things in the proper order. I know the only real one to do in a proper order is the Jacks A, Epsom Salt and then Jacks B

But how do I know, or how can I tell if I'm having nutrient lockout?

Most of the plants look good to great while the one large one has been struggling.

Their all the same strain, Strawberry Lemonade.

But the 2 large ones were 2 different seeds, so it could just be struggling compared to the other one because it's a different phenotype.

 

[Observationist]

fuck thats a clean lookin purdy system

does this help?

 

[Thegreywizard]

thanks for the props!

That is a nice chart, I'm trying to digest it now.

I really don't think my PPMs are too high. I even cut back on the Jacks just a little bit. 150-200ppms is from the Sugaree alone.

I'm going to do a water change tonight and track exactly how many PPMs each additive increases it.

I really want to upgrade to RO in the future, but as I mentioned for this run, not my place and not my choice, so I just have to do deal with it.

But just because my tap water is 300ppms, that doesn't mean I should reduce any of my additives does it?

Like basically starting at 300 is like starting at 0 right? That 300 doesn't actually count towards my real PPMs?

I was always confused by that and how it actually works when you're using tap water with a higher PPM.

 

[jguit]

where does your pH sit after mixing just the Jack's A/B and epsom? Maybe consider consider running Jack's on it's own and if you really want to add all of those additives, slowly introduce them and see what's causing your pH crash?

 

[jguit]

I was always confused by that and how it actually works when you're using tap water with a higher PPM.

It really depends on what’s actually in your tap water. I also have tap water with very high EC most of which is calcium but I also have a high level of chlorides which my plants do not like. I settled on a mix of RO and tap water. I’ll mix up Jack’s in plain RO to my desired EC and top up with my tap water to bring my pH up to where it needs to be. The alkalinity in my tap water helps stabilize my pH. You should check with your municipality and see if they can give you a water report or have one done yourself. It’d take a lot of the guessing out of things.

 

[Cashmeh]

Your setup is similar to mine. I'm assuming u transplanted. Did u happen to cut the roots when you did?

Large colony of bbs can lower ph, if there's lots of floating mass. Also 4 days.. 50 Gallon.. My ph starts crashing too lol.. Thats when I add nutrients. Since you have some leafs up top showing yellow, it makes me think the new nodes are using the N in your leafs. The trouble is, your ppms are so high, how do you just add N lol.. It's easy for me and my trio, I just add some micro.. But yea idk how you can.

Can we also see pics of your roots, I'm assuming they are pretty.

But yea my system ph dropped after 4, days, I'm 80 gallons 6 plants. I keep my feed low so it runs out early. I bet that's all it is. Generally if it was fine when you made the batch for days, it just wants a new batch. Sucks when you add all that though and it only lasts 4, days. If you ditch what you don't need it's easier to top off the nutrients.

 

[TryingToGrow]

I’d keep my water at 5.8 ish pH and only use 1 general purpose nute to about 1.2 ec, till figuring out what’s up with your pH.

My current tap water starts at 7.7 pH, 300 ppm and it will keep going up after pH’ed to 5.7, for at least a week, maybe forever.

I need to keep it in complete dark incase it’s algae causing it to happen. Don’t hear of pH dropping often

 

[TryingToGrow]

fuck thats a clean lookin purdy system

does this help?

View attachment 1200248

nice chart. If accurate, pretty helpful

 

[Thegreywizard]

I only have 3 weeks of flower left, so I'm probably just going to keep throwing everything at it lol

I need this run to finish the best it can. It's already only a partial run because things had some hiccups that turn into bigger problems along the way.

I plan on adding the Bluelab pumps for up/down (& silica) for a long term solution for PH swings.

But that will probably be late 2022, so if I can figure this out in the meantime, that would be great. But I guess it's gonna be after this run is done and I'm playing around in veg

 

[Og_punkgenetics]

So a constant struggle I seem to be having is my PH dropping down into the low 4's within 3-4 days of doing a reservoir change in my DWC.

I can't tend to my garden every day, I'm only able to go there twice a week.

I PH to 5.8-6.0, usually closer to 6.0 knowing it's going to drop rather quick over the next couple of days.

So what could be causing this in DWC?

I've read PH swing is common in DWC, but it's usually UP isn't it?

Having your PH consistently go down in DWC has to be caused from something else going on.

I plan on adding the Bluelab dosing pumps as an upgrade in late 2022. But until then I have to figure out the problem causing this now and correct it.

My nutrients:

Jacks A & B
Epsom Salt
Fulvic Acid Powder
Amino Acids Powder
Great White
Grow Genius
Enzymes
Sugaree/Sour Dee
Mammoth P (now that I'm in flower)
Budswel (now that I'm in flower)

I've been having this PH drop issue before I was adding Mammoth P Budswel, so I know it's not them. But I still wanted to list my full weekly regiment.

I'm really loving DWC and getting great results. If I can dial in exactly what's going on, I'm going to crush it!

Im assuming you are running co2. I had a similar issue once and found out it was because i wasnt purging out the co2 in the dark cycle. Co2 is miscable with water and coverts to carbonic acid on contact. Plants need 02 in the dark cycle anyway and if you are running a sealed room its best to cycle off the c02 awhile before lights out

 

[sagadella]

thanks for the props!

That is a nice chart, I'm trying to digest it now.

I really don't think my PPMs are too high. I even cut back on the Jacks just a little bit. 150-200ppms is from the Sugaree alone.

I'm going to do a water change tonight and track exactly how many PPMs each additive increases it.

I really want to upgrade to RO in the future, but as I mentioned for this run, not my place and not my choice, so I just have to do deal with it.

But just because my tap water is 300ppms, that doesn't mean I should reduce any of my additives does it?

Like basically starting at 300 is like starting at 0 right? That 300 doesn't actually count towards my real PPMs?

I was always confused by that and how it actually works when you're using tap water with a higher PPM.

Wanted to share my take on this based on personal experience, even though your post is now 8+ months old and I know you have long ago worked out your question with the extraordinary depth of knowledge and assistance on this site.
Last year I took over a hydroponics greenhouse raising lettuce. I had used aquaponics in the past but had to learn hydroponics on the run to try to save a friends greenhouse which had not been successful at bringing in a crop reliably and was about to be shut down. Starting from zero I scoured this and other sites looking for an answer as this was my issue too, and I couldn't easily find an answer. No one had been checking the EC of the system at all- EVER (Nor pH). System was using well water- which here in eastern NM has an EC of 350+. Previous grower ( also with experience only in aquaponics) complained that he had to cut the basic Miracle Grow recipe down to at least 1/2 and better 1/4 or all the plants turned yellow and had burned leaves and even then did not thrive and leaves were tough and bitter.
SO my first hard learned lesson was that there is only so much that can be dissolved in water. There is a saturation point after which nothing further dissolves. Obviously The safety margin for plants to thrive is within a very small window of this saturation window. If you are already starting with an EC of 300- then that is 300 less of other nutrients that you can additionally add and still stay within the window of plant tolerance. My understanding of EC is that it loosely represents the concentration of dissolved minerals, as does PPM in a different but similar way.
This is important because of how plants take up nutrients. If the concentration is higher in the water outside the plant than in the root system then fluids and nutrients will flow OUT of the plant rather than into the plant and I have seen this also drop the pH and it causes signs of nutrient deficiencies on the leaves and poor growth.
I am very excited about hydroponics and aquaponics and this site is my go to resource for growing cannabis and learning more about hydroponics.
Your DWC is my goal and I was very glad to see the pictures you provided to answer the question if it can be done and how. I'll follow your posts closely for more!

 

[sagadella]

thanks for the props!

That is a nice chart, I'm trying to digest it now.

I really don't think my PPMs are too high. I even cut back on the Jacks just a little bit. 150-200ppms is from the Sugaree alone.

I'm going to do a water change tonight and track exactly how many PPMs each additive increases it.

I really want to upgrade to RO in the future, but as I mentioned for this run, not my place and not my choice, so I just have to do deal with it.

But just because my tap water is 300ppms, that doesn't mean I should reduce any of my additives does it?

Like basically starting at 300 is like starting at 0 right? That 300 doesn't actually count towards my real PPMs?

I was always confused by that and how it actually works when you're using tap water with a higher PPM.

Wanted to share my take on this based on personal experience, even though your post is now 8+ months old and I know you have long ago worked out your question with the extraordinary depth of knowledge and assistance on this site. Starting from zero I scoured the site looking for this when it was my issue too and didn't easily find an answer.
I had recently took over a hydroponics greenhouse raising lettuce. Had used Aquaponics in the past but had to learn hydroponics on the run to try to save a friends greenhouse which had not been successful at bringing in a crop reliably and was about to be shut down. They had not been checking the EC of the system at all- EVER (Nor pH). System was using well water- which here in eastern NM has an EC of 350+. Previous grower ( also with experience only in aquaponics) complained that he had to cut the basic Miracle Grow recipe down to at least 1/2 and better 1/4 or all the plants turned yellow and had burned leaves and even then did not thrive and leaves were tough and bitter.
SO my first hard learned lesson was that there is only so much that can be dissolved in water. There is a saturation point after which nothing further dissolves. Obviously The safety margin for plants to thrive is within a very small window of this saturation window. If you are already starting with an EC of 300- then that is 300 less of other nutrients that you can additionally add and still stay within the window of plant tolerance. My understanding of EC is that it loosely represents the concentration of dissolved minerals, as does PPM in a different but similar way.
This is important because of how plants take up nutrients. If the concentration is higher in the water outside the plant than in the root system then fluids and nutrients will flow OUT of the plant rather than into the plant and I have seen this also drop the pH and it causes signs of nutrient deficiencies on the leaves and poor growth.

thanks for the props!

That is a nice chart, I'm trying to digest it now.

I really don't think my PPMs are too high. I even cut back on the Jacks just a little bit. 150-200ppms is from the Sugaree alone.

I'm going to do a water change tonight and track exactly how many PPMs each additive increases it.

I really want to upgrade to RO in the future, but as I mentioned for this run, not my place and not my choice, so I just have to do deal with it.

But just because my tap water is 300ppms, that doesn't mean I should reduce any of my additives does it?

Like basically starting at 300 is like starting at 0 right? That 300 doesn't actually count towards my real PPMs?

I was always confused by that and how it actually works when you're using tap water with a higher PPM.

I wanted to share a chart that was shared on THCFarmer but I do not know who shared it. I has saved my grow more times than I can count and taught me a lot at the same time. Hope its helpful.

 

[PK1]

Wanted to share my take on this based on personal experience, even though your post is now 8+ months old and I know you have long ago worked out your question with the extraordinary depth of knowledge and assistance on this site. Starting from zero I scoured the site looking for this when it was my issue too and didn't easily find an answer.
I had recently took over a hydroponics greenhouse raising lettuce. Had used Aquaponics in the past but had to learn hydroponics on the run to try to save a friends greenhouse which had not been successful at bringing in a crop reliably and was about to be shut down. They had not been checking the EC of the system at all- EVER (Nor pH). System was using well water- which here in eastern NM has an EC of 350+. Previous grower ( also with experience only in aquaponics) complained that he had to cut the basic Miracle Grow recipe down to at least 1/2 and better 1/4 or all the plants turned yellow and had burned leaves and even then did not thrive and leaves were tough and bitter.
SO my first hard learned lesson was that there is only so much that can be dissolved in water. There is a saturation point after which nothing further dissolves. Obviously The safety margin for plants to thrive is within a very small window of this saturation window. If you are already starting with an EC of 300- then that is 300 less of other nutrients that you can additionally add and still stay within the window of plant tolerance. My understanding of EC is that it loosely represents the concentration of dissolved minerals, as does PPM in a different but similar way.
This is important because of how plants take up nutrients. If the concentration is higher in the water outside the plant than in the root system then fluids and nutrients will flow OUT of the plant rather than into the plant and I have seen this also drop the pH and it causes signs of nutrient deficiencies on the leaves and poor growth.

I wanted to share a chart that was shared on THCFarmer but I do not know who shared it. I has saved my grow more times than I can count and taught me a lot at the same time. Hope its helpful.View attachment 1278117

just a friendly advise. This chart is missing two more pages and it's not fully accurate.