R/O water What the @#$% is happening with my PH! Help!

I hope that is not the temp for the res.with a plant.

superstoner1 said:

For every point on the ph scale it is twice as much.

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actually ph is on a log 10 scale which means 10x for each point

Ya know, i had that thought go through the weed induced fog of my brain right after i posted that and forgot to check it. Its been a long time since high school. Thanks.

cannabineer said:

When I ran a hydroponic grow (NFT technique, common reservoir) using salt nutes of my own device, I added a non-nutrient buffer salt. Even so, my pH rose fast enough that I needed to bring it down daily by 1/2 to 1 pH point. (I used nitric acid.) I have since learned that it had to do with ion balance. When the plant takes up more anions than cations (which was my case because I used only nitrate as the N source) the res pH will go up. GH Grow has 7:1 nitrate to ammoniac nitrogen; the Micro has 15:1. With those ratios I would expect a pH rise, especially with actively growing plants in veg. My 2¢ ... cn

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good shit... so what you need here is more ammoniac nitrogen and less nitrate nitrogen? what ratio do you prefer cn?

Nizza said:

good shit... so what you need here is more ammoniac nitrogen and less nitrate nitrogen? what ratio do you prefer cn?

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try some dynagrow they have a slightly higher NH4/NO3 ratio than many others.

I decided to let things run it's course over the last two days to see what happens..I did turn on my lower fan bringing rez temps down to 72 degrees at peak.

Yesterday at noon numbers.
Left pod (control)

• pH @6.3
• PPM @680

Right pod (active)

• pH @5.3
• PPM @480

note:huge drop in ph

Added 2 quart pure R/O water to top both off no nutes or ph balance.

Today's numbers
Left pod (control)

• pH @6.5
• PPM @675

Right pod (active)

• pH @5.9
• PPM @500

One plant showing signs of Manganese deficiency. I assume this is locking out because of high ph.
Getting ready for rez change today, Will bring ph down to low 5 to help.

As far as the nitrate vs ammoniac. I don't understand why this is an issue why do they set their hydroponic nutes the way they do if it could cause problems? Other wise my only option for the ammoniac nitrogen is Fox farm's Grow fert, it is only one I have that has higher levels of ammoniac in it. But it is organic is that going to be ok? I have Bio Bizz and Fox Farms nutrient lines from soil grow that I haven't been using since they are organic. Is it ok to use nutes with "live" cultures in them for hydro? I thought that the organisms would take over in the perfect growing conditions of the rez, but some people seem to use some organics to supplement still from what I could find.

I did stumble upon this today...
https://www.rollitup.org/marijuana-plant-problems/611057-p-h-problems-heres-good.html
It somewhat fits with what I have going on since levels have slowly been peaking out lower and lower. Hydroton just finally being neutralized?

Try mixing a batch using your tap water, or a 50/50 mix of tap and RO. I had the same problem when I ran ro. I've since switched to 100% tap, using the same brand nutes you use, and ph rise is now always slow/steady.
At least that's what worked for me. My tap is very high in Calcium Carbonate and has Chloramine rather than Chlorine, fwiw. Unless your tap water is bonafide toxic or something...

Trying out a half gallon of tap water in this mix([email protected] ppm@245 out of faucet) things looking good so far. It did take about 30% more ph down than usual to balance the tap, R/O water out at ph of 5.4. For the control pod I decided to keep same water in it, and will continue to balance the ph for the sake of getting it stable, but don't want to waste nutrients remixing...

Did you solve your problem? I had a similar problem until I started topping off with tap water and adding an algaecide initially upon res change

Just putting a closer up today. The tap water in the one pod did help keep things a little more stable than just the R/O water. Both pods this last week finally settled out and hold their ph nicely. I have come to the conclusion that the clay pebbles were the culprit. The reason I came to this conclusion was the fact that when the ppm's in the control pod stopped rising (pulling something out of the pebbles) the ph began to hold at any level I set it at regardless of the water or solution I was using. So for future reference instead of rinsing in hot water then soaking in neutral water like the manufacturer suggests I will soak in a nute mix with proper ph instead. I was just fighting the deposits in the pebbles till they finally leached out, so by doing the other soak should put them right with the world to begin with.

Thanks everyone for the help!!
Also for people having same issues with water don't disregard any of the suggestions that were made, even though some suggestions ended up not being an issue for me, they were all things you should check if your having problems too! Process of elimination is paramount!