Help - too little or too much? Fried tips and pH drops while EC rises and water level drops

RIG: DWC w/ top-down feed, 8-site res with four plants (two of each type). 3rd Week of Flower. Temps range from 72-84F with rh at 68-77%. KIND LED lights, RO water. 126GPH air pump with two stones - pump is outside my 4x4 grow tent.

Right about the flip my pH suddenly started crashing. At that point I was at 2.2EC and pH was stable. Suddenly, a day before the flip, my pH crashed to 4.1. No matter what I do, the pH keeps crashing and EC keeps rising. Plants are drinking water at a pretty steady rate.

I've repeatedly lowered my EC (currently down to 0.5) but keep having the same issues. When I'm at 1.0EC it raises overnight to 1.1 or 1.2, when I'm at 0.6EC it raises only about 0.05 overnight.

I have rinsed the res/roots with just plain pH'd water on two different occasions and done about a dozen res changes. Each time the EC rises and pH drops within 12 hours. Attached are pics of my roots (I don't think I have root rot, but you tell me - using hydroguard staring about a week ago, 2ml/gal) and what appear to be fried tips, which suggests over-feeding.

IS THIS POSSIBLE: I have two strains in the same res (supposed to both be indica-dominant hybrids, but one is very tall and the other short and bushy). Presumably they have different appetites. Could I be UNDER-feeding at least one of the strains to the point where the osmotic pressure is higher inside the plants (or some of them) than the res, then nutes leech into the res and EC goes up and pH goes down???

Water level is continuously going down, so maybe that's not the case.

I am running a pretty similar set up to you. Dwc 6 plants 2 different strains but i guess im lucky they both feed the same. RH is quite hig for flowering, from what I understand RH can if its to high affect your ec levels as plants struggle too uptake nutrients, are you sure you e.c and PH pen are both calibrated? Not meaning to be demeaning but you gotta start somewhere right

There are far more knowledge people on here than me but I’m a noob whose had a lot of issues when I started so I’m more than happy to put my 10 cents in im sure someone who really knows what they are on about will help you get it sorted

Marcorfl said:

I am running a pretty similar set up to you. Dwc 6 plants 2 different strains but i guess im lucky they both feed the same. RH is quite hig for flowering, from what I understand RH can if its to high affect your ec levels as plants struggle too uptake nutrients, are you sure you e.c and PH pen are both calibrated? Not meaning to be demeaning but you gotta start somewhere right

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Hi, yes I agree the rh is high. I ordered a dehumidifier and am going to install it tomorrow, so hopefully that helps. My EC and pH pens are calibrated, but you're right - gotta start somewhere.

At the moment I'm trying hydroguard and frequent res changes to fight the issue. Will lower RH and see where that gets me. Thx

razingthebar said:

Hi, yes I agree the rh is high. I ordered a dehumidifier and am going to install it tomorrow, so hopefully that helps. My EC and pH pens are calibrated, but you're right - gotta start somewhere.

At the moment I'm trying hydroguard and frequent res changes to fight the issue. Will lower RH and see where that gets me. Thx

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I would personally say if your ec is going up and ur ph down then it should be that you’re over feeding 2.2 ec for third week of flower is very high in my opinion, Ive never got close to that im currently growing to indicas pretty heavy feeders and 1.7-1.8 is my sweet spot, they’ve probably uptaken too many nutrients and will keep leaching it bavk into res for a bit but if you lower it a fair bit over time they should level out but its probably gunna be frustrating constantly changing but its a learning curve, what nutes are you using?

Roots are on the verge of rot.
What’s the res temp?
Does light get inside the res?

Dont mind the arrows and check marks.

Merkn4aSquirtn said:

Roots are on the verge of rot.
What’s the res temp?
Does light get inside the res?

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Water temp is higher than I would like. Water temp is around 65-77 degrees. I don't have the ability to add a chiller at this point, but am working on getting the rh down with a dehumi, but not sure what more I can do about the res water temp.

No light getting in, other than when I remove a net cup to top off or change water (although right now that's twice a day since my pH is dropping almost into the 3s).

Researching H202, but I"m seeing mixed messages here and elsewhere.

Hotshotmaple said:

View attachment 4643480
Dont mind the arrows and check marks.

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Hey, thanks! I found this on another thread.

Someone told me this was meant for veg only (where pH tends to naturally rise), and not applicable to flower (where pH tends to naturally fall).

One thing that got me are these two scenarios which, according to the chart, call for very different responses:

* Water falling, EC (barely) rising, pH falling - says to lower EC and do a res change
* Water falling, EC "static" (if my EC goes up 0.04 is that statis or rising?), pH falling - says to RAISE EC if under 1.0

Two completely opposite directions and which do you follow when EC is only rising VERY slightly...

But thank you, this chart is helpful. As usual, one answer leads to more questions!

Dont change too much at once. Still not sure what nute ur running, may have missed it. Dont think h202 works with organics but not my method so check that! Do your buckets smell rotten? Is there pieces of dead roots? If not then root rot is not your issue yet...

H2O2 did not work for me. My plants were way smaller tho.
I am now trying beneficial fungi. Basically just great white or any other myko product.

If its only rising slightly your barley over feeding. Whats ur ph balance method?

Hotshotmaple said:

If its only rising slightly your barley over feeding. Whats ur ph balance method?

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I am changing the res often now to combat this issue. Here's my current approach:

* Fill bucket with RO water, add nutes (Lotus Nutrients), aiming a little higher than what I want the final EC to be, and let it sit for 24 hours
* Check EC and pH next day. Add RO water to bring EC down to desired level - I was getting burnt tips, so I've been walking it back from 1.0EC and am currently at 0.5
* Add hydroguard (2ml/gal)
* Drain res - add plain pH'd water and drain again to get the stuff at the bottom my pump wouldn't reach
* Check pH of new water and add a little pH down (my tap is about 7pH) - nutes say they level pH at 6 but that's not my experience
* Check again EC and pH once the res is mostly filled so I can add plain water or balance if needed

If I'm checking after a res change:

* I check EC and pH with meters. Currently EC is rising and water and pH are falling, so I add plain pH'd water to get the EC back to where I want it.
* pH is dropping into the 4s every 12 hours, so I end up adding plain water (about 7pH) and then still have to add some pH Up to get it back to around 6.0pH

Happy to take pointers, as this is my first grow.

Im unfamiliar with ph balancing nutes and ro water, i run well water and non balancing nute. Cant say not knowing but im not sure if they work together or if this would be the reason for the swings? Double check if the nutes and ro are a good combo