Cannot figure out cause of rapid ph drop

From what I c, pet flora and ss1 could be on to something.

What is your water temp, water level in beckets and rez size?

I suspect nute temp too high-----DO level too low----not often enough nute changes.

gotta be something-----hand with it,

A~~~

My ph has been stable at 5.8 for 2 or 3 days since the res change. I think I was running the ppm too low before. I wrapped my new buckets in 3 layers of reflectix... it made a huge difference. Like 10-12*

I second the small reservoir idea. I had a similar problem in a "rainforest" bucket setup.

Barrazaburnz said:

I second the small reservoir idea. I had a similar problem in a "rainforest" bucket setup.

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It is not the small reservoir or the rainforest buckets. I've ran both no issuses, until water temps get out of line. Bigger reservoirs just have more volume so the temps remain more stable.

I just had a similar situation where my pH dropped from 5.8 to 3.2 overnight! I adjusted back up and added more water, and the same thing happened the following day. Up until that time, my pH had been rock solid from res change to res change, with this occurring in week 4 of flower. I had been running very light nutes about 600 ppm, ½ of what GH reco’s, and everything was looking good, so I didn’t feel the need to change.

I ran across a post by Woody at thctalk.com ( post #5 http://www.thctalk.com/cannabis-forum/showthread.php?74561-DWC-problems-please-help-!-Medical-grow) where he wrote that at this stage in flowering, she is using up lot of N and K, but not much P, which offsets the pH since P is (-). His solution to this is to increase the PPM’s, so that there is still N and K left to balance out the unused P. He targets 1.4 EC, which is about 1000 ppm. I tried this technique, and I’m looking good now, back to being stable at 5.8 for the last 3 days. Fingers crossed that it was this simple.

Update us in a week or so how the ph is if you think about it. When I finally got my ph stable my pen drastically lost calibration by over 2 full whole numbers which I didn't figure out until my yield was already fucked. Now it has to be calibrated weekly to stay accurate.

I have had the same issue on flower; however, not quite as dramatic. My nute res completely empties after 4 days, and the ph drops substantially. So I have resolved to check on the girls at least once a day. Top off with water and adjust the nutes. Wait a couple of hours, and then usually have to PhUp it... not much but, I really like to keep the PH solid at 5.8. The girl have really done well this time around. (Full res flush is once a month!) (im using the gh m g b series and have been pretty happy with the results!)

Malevolence, when I got that first 3.2 reading, my heart skipped.... After double and triple checking, I broke out the 7.0 calibration solution, re-calibrated, re- checked and also checked my usually 7.1 tap water. After all that I was still getting the 3.2 to 3.3. I'll definitely repost my results in a week as I'm not claiming victory yet. I lost a couple plants when my pH spiked due to high res temps/root rot and I didn't react properly. Since then I ditched the pH strips and got a digital pen which I calibrate weekly at res change, whether it needs it or not. That grow had so many issues so now I'm paranoid, which is why I have been using such light nutes. With the dead plants, I had nute burn, but since the pH was always off, it was impossible to tell if it was due to lockout, or because the solution was too hot but I've been using lite nutes since then. I'll fill you in next week.

gregorym said:

I have had the same issue on flower; however, not quite as dramatic. My nute res completely empties after 4 days, and the ph drops substantially. So I have resolved to check on the girls at least once a day. Top off with water and adjust the nutes. Wait a couple of hours, and then usually have to PhUp it... not much but, I really like to keep the PH solid at 5.8. The girl have really done well this time around. (Full res flush is once a month!) (im using the gh m g b series and have been pretty happy with the results!)

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Yea those bitches will empty a bucket fast. I usually top up every 2 - 3 days.

As i was reading through everything here sounded eeriely familiar... I ran DG in my stinkbud system 2 years ago and fought the PH swing everyday. Sucks having to go out and adjust everyday. I attributed it to having such a small res, mine was maybe 8gallons, feeding 10-12 plants in a stinkbud fence post system. I about lost my whole crop when my wife went into labor and i didnt come home for 2 days. Ridiculous to think i couldnt stay gone any longer than that w/o having major issues. I hope we find a solution because back when i was running that setup no one ever had the PH going down and PPM going up issue. I think it goes back to the dyna and maybe a small rez, i always like most others on this thread ran pretty low PPM.

Does anyone else have a fan or dehumid close to the res in his/her room? What size res's is everyone that is having the issues using?

superstoner1 said:

First thing i would say is try a different nute and see what happens.

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Ye i also agree w mr stoner. I had the opposide, went from 5.7 - 6.2. every night. I was using HESI, because ran out of nutes GHE.

Just flush clean, and added the GHE, and its back to normal again.

how to control your PH...
There are a couple factors that cause your PH to drift. The most common is running the nute solution too strong or too weak. If it's too strong, your PH drops. If it's too weak the PH rises. You have to find the balance point. If you find that the formula above is say, a little strong, and say you have a 20 gallon ressy, mix the nutes for 18 gallons. If it's a little weak, mix it for 22 gallons. You follow?
The other common mistake is mixing your nutrient solution and trying to adjust the PH right away. You have to allow time for the ph buffers in the nutrient solution to do their job. Mix the nutes up, and bubble or circulate for 12 hours before even looking at your PH. You will find the PH to be almost right on target.
I use little or no ph adjusters. (Except during flush). I use tap water, with a starting PPM of 300-400 and a starting PH of 7.4-9.0 (Thats crazy you say! The water is too hard, you will never get stable PH and you will have too much Ca, causing a lockout of Mg!) Bollocks I say.
Every week, on Friday I drain the ressy and fill with plain water. I let that run overnight giving the plants a little flush. This also allows the chlorine and ammonia to evap. On Saturday morning, I mix the nutes into the ressy. I DO NOT adjust ph at this time. Let that run as is overnight. On Sunday morning, I check ph and adjust if needed. Usually don't have to.
Doing things this way has saved me from constant PH drifts, and using about 150 ml of ph down every ressy change, and a little here and there throughout the week to keep it in the desired range. Now, the most I ever have to use is about 30 ml.if any at all. (I have a 35 gallon ressy btw) My Ph stays at a constant 5.5-5.8.

If you are still having PH issues using the above method, an alternative is to PH adjust the plain water to 5.5 BEFORE you add nutes.

TMG Genetics said:

how to control your PH...
There are a couple factors that cause your PH to drift. The most common is running the nute solution too strong or too weak. If it's too strong, your PH drops. If it's too weak the PH rises. You have to find the balance point. If you find that the formula above is say, a little strong, and say you have a 20 gallon ressy, mix the nutes for 18 gallons. If it's a little weak, mix it for 22 gallons. You follow?
The other common mistake is mixing your nutrient solution and trying to adjust the PH right away. You have to allow time for the ph buffers in the nutrient solution to do their job. Mix the nutes up, and bubble or circulate for 12 hours before even looking at your PH. You will find the PH to be almost right on target.
I use little or no ph adjusters. (Except during flush). I use tap water, with a starting PPM of 300-400 and a starting PH of 7.4-9.0 (Thats crazy you say! The water is too hard, you will never get stable PH and you will have too much Ca, causing a lockout of Mg!) Bollocks I say.
Every week, on Friday I drain the ressy and fill with plain water. I let that run overnight giving the plants a little flush. This also allows the chlorine and ammonia to evap. On Saturday morning, I mix the nutes into the ressy. I DO NOT adjust ph at this time. Let that run as is overnight. On Sunday morning, I check ph and adjust if needed. Usually don't have to.
Doing things this way has saved me from constant PH drifts, and using about 150 ml of ph down every ressy change, and a little here and there throughout the week to keep it in the desired range. Now, the most I ever have to use is about 30 ml.if any at all. (I have a 35 gallon ressy btw) My Ph stays at a constant 5.5-5.8.

If you are still having PH issues using the above method, an alternative is to PH adjust the plain water to 5.5 BEFORE you add nutes.

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tmg change to a 5-10gal res and do a run. Then come let us know if your method still works.

30ml in a 35gal res?That's a lot. I use less than a gallon a year with 220-250gal in my RES's running a perpetual garden.

What i have found is over a period of appr. 7-8 days my water stays pretty constant, or rises slightly. After that it will drop and at first i added up but just no way to keep it level. Now after 7-8 days i do a change and always stays constant. I am running 135L if water and keep nute levels around 600-700 in flower. I am still trying to figure this nute thing out lol. Once i think i have found a pattern of it going up and down it changes lol.

few things i've learned...
add cal-mag first always (unless using silicates which get added before the cal-mag) this will make your pH reading be more accurate because of the ways the nutrients buffer with eachother
then add your base nutes
then your additives

also don't use magnetic drive pumps, only use black rtv silicone sealant for builds ( used on fish tanks)

clean your airstones

check buckets before to make sure they aren't translucent--if they are wrap it with something.. (i use black plastic then reflective bubble wrap because it helps reflect and insulates at the same time!)

also be aware that any root rot (overwatering /overheating usually) will rot, thus increasing ppm's and changing your pH

the best test for rot is your nose... just smell the medium it shouldn't smell rotten.

if chunks of roots are breaking off maybe your water is being agitated too much

also maybe you are using too high of a nutrient strength... i max out at around 900 ppm using protekt, dyna foliar pro, and humboldt honey hydro, but only run drain to waste now so I only monitor in/out pH, and it's fine, so i can't fully relate to your dwc grow

I had pH pen problems too. This grow I keep it in a 7.0 solution, much better keeping it in solution

I was having pH issues with the last 1/4 of my Hydroponic Research V+B. New jar no problems

Malevolence said:

Update us in a week or so how the ph is if you think about it. When I finally got my ph stable my pen drastically lost calibration by over 2 full whole numbers which I didn't figure out until my yield was already fucked. Now it has to be calibrated weekly to stay accurate.

Click to expand...

"I had pH pen problems too. This grow I keep it in a 7.0 solution, much better keeping it in solution".........
Actually bluelab recommends 4 or plain tap water

I read most of this and honestly havent learned anything. I am using Sensi AB with Heisenberg tea and a little protekt, my ph is going from 6.0 to 5.0 over 24 hrs 2nd wk flwer. PPM is completely stable and plants are drinkin up water. Has anyone found an actual cause?

Gifted0ne said:

I read most of this and honestly havent learned anything. I am using Sensi AB with Heisenberg tea and a little protekt, my ph is going from 6.0 to 5.0 over 24 hrs 2nd wk flwer. PPM is completely stable and plants are drinkin up water. Has anyone found an actual cause?

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Root rot.......