DWC Problems PH PPM unstable I'm looking for some professional help

I've experienced a long term problem and I am looking for someone who can point me in the right direction for some professional help. I run a DWC using General Hydro waterfarms ie. bubbleponics. No mater what combination I try, I can not get the ph and ppm to hold stable. Which direction the ph varies depends upon which media I use but the results for any plants are always the same.

Background info:

Long term DWC grower with years of success at this location.
City Water is normal source
Environmental Conditions always perfect no what time of year. Seriously.
Results are the same for plants. GH nutrients, Canna, RO water or city water ( I've tried multiple locations)
The ppm is read on x500 scale

The problem I have is..... no mater what I do, The DWC will not hold a stable nutrient solution.

If I run hydroton, the DWC will go from a starting point of 550ppm @ 6.4 ph but in 24 hours this will be 770ppm @ 3.5 . Another 24 hours and the readings are 820 @ 3.5 Obviously plants die.

At this point I just run water and nutrient tests.


If I run sunleaves rocks the DWC will go from a starting point of 580 @ 6.4 but in 24 hours this will be 630 @ 7.0 Another 24 hours and the reading are 640 @ 7.0 Plants Die but it takes longer.

RO water yields the same reaction / failure.

Water from other municipalities yields the same reaction. (other water sources at my location fail)

Washing the system and running it at another location yields the same reaction. (my water at another location fails)

Grodan big mamas hold ph / ppm when run in the waterfarms but the plants show signs of multiple contradictory deficiencies.

Water recirculating through the system but not dripping over grow media the system holds stable ph / ppm. It starts to fail when dripped over grow media (with exception of big mamma / grodan media although plants are still quite unhappy.

Water or nutrients in reservoirs hold constant ph / ppm. 1 week , 2 weeks or three weeks later the ph / ppm will be stable.

If I take my equipment including rocks that have "failed" at my location and thoroughy wash and rinse at another location and run the hydroton or sunleaves at that location, the system will hold stable ph / ppm as long as I leave it at that location ( ie. 3 to 4 days of dripping ). If I bring that same bucket with that same water/ solution to my location, it will fail (ph drops and ppm start rising for hydroton)




If I try " chasing" a running ph level with PH up or down, I get a white cloud in my DWC. I can add up or down every few hours and it's like it drops right out of the DWC (see attached photo of bottom of waterfarm bucket) Up or down depends upon the type of media.

Here is a water report I had done by Colorado Health and Human Services.....


Calcium 24 mg/L
Silicon 4.8 mg/L
Potassium, 1.6 mg/L
Sodium 7.8 mg/L
Magnesium 1.7 mg/L
Copper .3 mg/L
Lead .0048 mg/L
Hardness 80

I have sought assistance at Canna, GH, Plant It, CHHS CSU and numerous others with no further insight than when I started.

Any help or insight would be greatly appreciated or point me in the right direction because I'm pretty tired or the looks of my own tail.

Uhm.. The plant is intaking nutes...

OF course it won't hold a stable nutrient solution.

Are you sure you have years of experience?

Once you realize that plants intake nutrients at different rates, you will then clue in that the PH will also change, along with the level of the nutrient solution in the bucket, which will become lower, as the PPM's rise..

As long as your plants are growing right, it's all that matters.

Since the DWC goes from a 6.4 ph to a 3.5 in 24hours, the nutrient solution has turned to acid by day two. Plants will not live, they take forever to die. Roots appear white and healthy for weeks but grow away from the drip rings and stay under the grodan 2x2. Eventually the plant will die from no nutrients available in the DWC. If the DWC is flushed and replaced daily, it will still turn to acid daily.

I fully understand the relationship between ppm and ph in relation to plant uptake. Certainly not my first rodeo. At this point I do not put plants into the system. I am merely running test buckets to try and determine what variable causes this chemical reaction. I say it is a chemical reaction because the good folks down at CDHHS informed me that no known bacteria is known to cause this rate of ph drop. The possibility exists that it could be ionic. I guess that's what I'm here to research.

If you read through my above post, it is still undetermined if the problem is environmental or water. The testing points to both.

I realize there is a lot of information above. It takes awhile to digest.



Things tried..... Physan 20, replaced entire system, radon removal (long shot but what the heck), bacterial resistant paint on all walls, RO
different mediums. Still all fail.

Change nutrient brands... get a new tester... calibrate old one...what happens to the ph of straight water when run by itself?

Is that sodium level high for tap water?

Scroga said:

Change nutrient brands... get a new tester... calibrate old one...what happens to the ph of straight water when run by itself?

Click to expand...

I've changed nutrient brands with same results. Several times.
I use a blue lab guardian continuous tester. 7 and 4 calibration points. I have 3 of them plus an echo pen. All same results.

Ph of strait water holds ph and ppm perpetually as does nutrient mix........ as soon as it bubbles over the rocks the variables of ph and ppm change or rather start changing.

Strait RO water will fail also..... start at 0ppm @ 7.2ph and it will go to 400ppm and 3.5 but usually takes 36hours to hit this level. This is with hydroton. With the shale type sunleaves rocks the ppm goes up and ph goes up. It appears the chemical reaction causes different leaching depending upon the medium. Results for plants however are still the same. Slow stalled death.

I'm not sure on sodium. I would assume RO removes that but I'll check.

Mate I think it's time to switch to Hempy... is it the net pots? Mate I feel for ya that's a real confusing one..? Some component must be toxic and leaching into the system...

So if you don't go above the net pot you don't have a reaction?

ph drop like that is usually from pathogens in the water. need to use bennies always with dwc for root rot prevention... I use aquashield. warm water (above 70*), organic nutes/additives, and light leaks will all make it worse. pond-zyme also works well and lasts forever.... can be bought at petsmart and petco.

tap water should float back up pretty quick after mixing up a new res, but should stabilize after a few days as the ph buffers do their thing and the tap water gasses off. Just keep adding ph down.

try mixing up a res / nutes adding aquashield with dechlorinated tap water and ensure 100% darkness in the res. expect ph to drift up for a couple days... just correct it.

There should be no need to drip feed from the top; raise the water level in your bucket up to the rootzone instead.

The real problem is as Hydroburn said, there are pathogens in the water, the pathogens are there, because you put the light to close to the tops of the buckets, you're mixing your nutes to strong and it's to early for them to be getting nutes that strong.

So the nutes aren't being used, the water is being evap'd and its causing root rot to form up and the PH to swing to lows.

The solution provided by Hydroburn is the correct one.

Fill your buckets to the top, eliminate the drip feeds, raise the lights a little so it doesn't heat the buckets up so much.

No need to switch to Hempy buckets. No need when DWC is proven efficient and effective.

PS: You should expect a PH swing of some sort as the nutrient solution is used up by the plant.

Hydroburn said:

ph drop like that is usually from pathogens in the water. need to use bennies always with dwc for root rot prevention... I use aquashield. warm water (above 70*), organic nutes/additives, and light leaks will all make it worse. pond-zyme also works well and lasts forever.... can be bought at petsmart and petco.

tap water should float back up pretty quick after mixing up a new res, but should stabilize after a few days as the ph buffers do their thing and the tap water gasses off. Just keep adding ph down.

try mixing up a res / nutes adding aquashield with dechlorinated tap water and ensure 100% darkness in the res. expect ph to drift up for a couple days... just correct it.

There should be no need to drip feed from the top; raise the water level in your bucket up to the rootzone instead.

Click to expand...

I tried the pathogen / sterilization approach with no luck. By that I mean...... Microbial tea failed, aquashield failed, replacing anything and everything that touched water with new equipment including chiller, barrels, rocks, pumps etc. and failed.

After that I started recording the time it takes for the dwc to turn to acid. I discussed my findings with CDHHS chemistry and biology departments and they both informed me that it had to be chemical because they know of no known bacteria that can act this fast. So either I have an unknown strain of bacteria or it is a chemical reaction.

eg. 2pm 670 6.5
3pm 670 6.7
6pm 680 6.8
9pm 680 6.8
midnight 680 6.7
6am 700 6.3
noon 710 6.0
3pm 710 5.7
8am 740 4.7
10pm 740 4.6
10am 790 4.2

Chasing the ph leads to a white cloud in the recirculating reservoir. I believe I have a picture posted above. It is impossible to hold ph.
I can add amounts every two to three hours of up or down (again depending upon medium used) and it will go back to climbing / dropping. H202 stalls the reaction process but only briefly. By that I mean for a couple of hours.

Bubbleponics is dripping from the top. I use the waterfarm system not an ebb n flow. It is a very large system (s). I should point out that I tried switching to coco and still had the same reaction . Things lived, it was less than stellar and showed similar results as when I tried the big mama grow blocks in the waterfarms. The plants deformed and shown contradictory sighs of deficiencies / overdoses. They grew and finished but it was nothing to be proud of.

Here is a picture of what chasing pm stability looks like with Heisenberg's tea.....(above) no effect on ph stability. The second picture is when I add ph buffer every few hours and chase the ph to hold steady. It looks like it drops out of the dwc before it makes the first bucket in the recirculation chain.


Anywhoo......... I really am looking to make contact with someone with a water chemistry background. It must be a chemical reaction or my experiments with bleach, physan 20 and h202 would have yielded positive results. I think the CDHHS people know much more than I do about water and it was their opinion also.

I am switching to soil to get something rolling but 3 yards of soil in my house is not something I will be smiling about. I hear it is like going from a Ferarri to a bus but hey, the ferarri won't start so what ya' going to do.

Scroga said:

So if you don't go above the net pot you don't have a reaction?

Click to expand...

Correct. However, test buckets with rocks soaking in a tub of water yield the same results. ie. ph surge or drop depending upon the media.

It appears when the water comes in contact with the media either leaching occurs, a chemical reaction or both.

If it is microbial it is an unknown species and I should be getting a research grant to study it.

More info on my water analysis.



Test Water Limits ppm


Iron - 8.3 ppb .0083 ppm 2.0 - 10

Barium 32.7ppb .0327

Molybdenum 2.6 ppb .0026 0.01 - 0.05

Nickel 6.5 ppb .0065

Boron 13 ppb .013 0.5 - 5.0

Copper .3 .1 - 0.5

Lead .0048

Hardness 80

Chromium < 1 ppb

Vanadium < 1 ppb

Zinc 289 ppb .289 0.5 – 1.0

Manganese 4.4 ppb .0044 0.5 - 5.0

Strontium 121 ppb .121

Cobalt < 1 ppb

Aluminum 28.5 ppb .0285

Beryllium < 1 ppb

Arsenic < 1 ppb

Selenium < 1 ppb

Silver < 1 ppb

Cadmium < 1 ppb

Antimony < 1 ppb

Thallium < 1 ppb

Uranium < 1 ppb




Calcium 24 mg/L 100 - 500

Silicon 4.8 mg/L

Potassium, 1.6 mg/L 100 - 400

Sodium 7.8 mg/L

Magnesium 1.7 mg/L .05 – 5.0




NPK of GH fertilizer NPK of Cana Substra


Micro: 5. 0. 1 Part A 4-0-2

Grow 2. 1. 6 Part B 1-2-4

Bloom 0. 5. 4 Canazyme 0-2-1

Rizotonic .6-0-.6

In all the years I have been growing the one thing I have learned is that the more complicated you make it. The more complicated it becomes.

are you using tap water conditioner? I don't see chloramine mentioned in your analysis, but chloramine will/can sterilize your bennies. If I don't use a little API tap water conditioner when I change my res, I get slimed no matter what I use... every, single, time.

are your containers 100% light proof? you should be able to hold it up to an HID and pass your hand behind it without detecting the shadow of your hand at all. From your pics, the buckets look thick, but just looks like white tidy cat buckets or something.

what is the water temp? sorry if I missed it... should be around 65 - 68 ideally... you can run a chiller... or wrap the containers in 3 layers of silver bubble wrap from home depot, or other insulation to help hold temps and guarantee it is light-proof. Swap out a 1L frozen bottle of ice every 24 hours.

Aquashield and pond-zyme should be a good combo, but gotta make sure no chloramine... the tea has failed me before and I never recommend it anymore. I would stop using rhizotonic until you get shit figured out... a lot of stuff like that is known to trigger slime blooms.

Not likely you will find any professionals or water experts on rollitup, but a lot of us have dealt with root rot and water issues many times. It is typical for slime and algae to appear fast in dwc. Once, I added liquid karma and fulvex to my res (organic additives) and 12 hours later I was slimed... had to trim the roots down and rinse them out with bleach water. The good thing is it was easy to correct and the plants rebounded in a couple days.

One last thing people don't always think about is make sure the grow area and entire house is clean. people that have pets obviously shouldn't keep a filled up litter box or have dog shit everywhere, pet fur and dander in the air can carry microbes... dusty air vents, mold, dirty laundry... all can make it harder to keep a clean grow.

Hydroburn said:

are you using tap water conditioner? I don't see chloramine mentioned in your analysis, but chloramine will/can sterilize your bennies. If I don't use a little API tap water conditioner when I change my res, I get slimed no matter what I use... every, single, time.

are your containers 100% light proof? you should be able to hold it up to an HID and pass your hand behind it without detecting the shadow of your hand at all. From your pics, the buckets look thick, but just looks like white tidy cat buckets or something.

what is the water temp? sorry if I missed it... should be around 65 - 68 ideally... you can run a chiller... or wrap the containers in 3 layers of silver bubble wrap from home depot, or other insulation to help hold temps and guarantee it is light-proof. Swap out a 1L frozen bottle of ice every 24 hours.

Aquashield and pond-zyme should be a good combo, but gotta make sure no chloramine... the tea has failed me before and I never recommend it anymore. I would stop using rhizotonic until you get shit figured out... a lot of stuff like that is known to trigger slime blooms.

Not likely you will find any professionals or water experts on rollitup, but a lot of us have dealt with root rot and water issues many times. It is typical for slime and algae to appear fast in dwc. Once, I added liquid karma and fulvex to my res (organic additives) and 12 hours later I was slimed... had to trim the roots down and rinse them out with bleach water. The good thing is it was easy to correct and the plants rebounded in a couple days.

One last thing people don't always think about is make sure the grow area and entire house is clean. people that have pets obviously shouldn't keep a filled up litter box or have dog shit everywhere, pet fur and dander in the air can carry microbes... dusty air vents, mold, dirty laundry... all can make it harder to keep a clean grow.

Click to expand...

Dude, your not listening... it's not pathogens...if it was the ph would be rising...
P.s. house and garden roots excel used as an inoculant will keep the slime away...

dude.. your advice "try hempy buckets" and "toxic leaking components" is pretty much shit too.

Ops words bro... he. Says it's happening in a separate test bucket with water and hydroton

Why? The ops traced it back to his media as it still happens in a test bucket separate to his system , the hempy suggestion was just meant to be something he can get on the road so to speak, as op was saying he has lost a lot of time trying to figure this and get it sorted ... was by no means implying that hempy is better than dwc... I grow dwc

P.s buddy I never said your advice was "shit" simply a mis diagnosis...