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dwc ph

I see lots of ph issues here on the forum with hydro and I'm having them too. first week rose .3, no problem. nute change and in 50 hrs rose .6. put me over the limit so I changed again. rose a full point in less than 24 hrs. we ph our nutes down to 5.7 because we figure it will rise a little, but it kinda out of control now. any ideas? changing out so often kinda sucks.
 
when adding water/nutes, are you letting them rest in your res a while before measuring & adjusting pH? or do you just measure and adjust straight away?
 
I haven't got any personal experience with DWC but I remember reading somewhere around GWE that it should rest, I'm thinking at least an hour to be really accurate, but I'm not 100% sure. Can't remember the exact time, I'll try hunt it down or someone who knows more about DWC should be along soon
 
found this, don't know if it helps at all "Why does the pH of the nutrient-water go up right after I put it in the reservoir?

Get a General Hydroponics pH test kit on Amazon - almost a necessity for growing cannabis in DWC!
The pH of the water in a reservoir can change for many reasons, but when it happens right after you changed the reservoir, it may be because the water was sitting for a while and is now being agitated. Bubbles from the air pump move the water around, especially on the surface; this movement raises the pH of the water in addition to aerating it. This may be less noticeable if you shake your water up well before testing the pH and adding it to your reservoir.

In any case, after about an hour, you should notice the pH stays more stable (and that's the pH level you should pay attention to).

There are a few other factors that change your pH over time. Your roots give off waste products that affect the pH, and as roots use up nutrients at different rates that can also alter the pH.

One thing you can do to help stabilize pH is keep your water level about 2 inches below the bottom of your net pots. A bigger reservoir has a more stable pH, so making sure your reservoir is always topped off will help improve pH stability. On the flip side, the air gap helps prevent the hydroton from affecting the pH, keeps stems from getting mushy, and also helps roots get more oxygen."
 
haha! just went there! so now I guess the question is... once I find out how much it will rise in the bubbles, do I just ph my mixing tank factoring in the known elevation? where are hydro people? lol.
 
Tell me about your setup. What are the temperatures? What's your process of reservoir changes? What nutrients are you using?

DWC is very much a science. The process matters.
 
The day before I change reservoirs or top off my plants I fill up my extra buckets and let them sit 24 hours. This helps with chlorine and makes the water room temperature. The next day I add my nutrients depending on stage of plant. Flora Micro first Flora Bloom and Flora Grow if applicable. Then I add Epsom salt and hydroguard. Stir. Check pH. Add pH up/down. Stir. Check pH. Adjust according to plant. Change reservoir.

After growing DWC for a couple years I only spot check the pH anymore. My water is 7.8ph from tap. On every Saturday or Sunday I change the water for all my plants. Depending on which nutes I use each of my buckets takes between 14-18ml of pH down to achieve 5.6ph. The pH of my plants typically increases to 6.2-6.5 by Wednesday when I top off all of my plants. I add light amounts of nutrients to the top off and pH to 5.6.
 
temps now are 69, by the weekend could reach 78. using GH flora trio, calmag, hydroguard. 35 gallons nutes. 10 airstones. pretty much same run as you except I haven't been letting the water sit over night. nothing to really top off yet either, roots are just now reaching the nutes. only lose a llittle over 1/4 inch in a week.
Epsom salts?
 
DWC is challenging at first. The main reason I let the water sit overnight is because of the water temperature. I use water in my basement running straight from the utility. The water is cold, between 45-50 degrees. That temperature can shock you plants. My ph rises usually 1 point over a cycle. I set my ph low to account for that. I use Epsom for the magnesium. It's cheaper than calmag plus.

Are you plants healthy?
 
nice tips! my water bout the same temp out the faucet. gonna let my water sit then after this. my plants still look fine, just want to get on top of it before they dont !
thanks again
 
Hi intergalactic_harvester,
I am a DWC grower and I try to keep the water and nutrient mix at a pH level of 6.0 within the range of +/- .5. Because of my grow location (not handy to a faucet) I use one gallon jugs (washed milk jugs) to feed or add water at mid week. I first bring the water to 6.0 and then add the nutrients to the water of one of the jugs and balance the pH again. At mid week, I top off the reservoirs with plain pH'ed water (it's been running around 2 - 2 1/2 gallons per reservoir). I check the pH of the reservoir before topping off, if the reservoir measures between 6.5 and 7.0, I balance the water to the low side of 5.5, add it to the reservoir,stir it up and recheck it. Only if the pH is outside of the range of 5.5 - 6.5, will I then adjust it some more to bring it within range. I read that different nutrients are absorbed at different pH levels, so it is better to let the pH range vary a bit. Be patient and do not try to change things too quickly.
Good luck with your grow.
 
thanks dw2. checked after work and sitting at 6.1. 5.9 before bed last night so i guess im doin ok. my roots are just hitting the water now so i dont top off during the week, only dropping about 1/2 inch thru the whole week. maybe a partial changeout mid week if i need to adjust? at least until the plants are using enough to lower the water for me. going dwc on my first grow is really challenging right now getting the hang of it, but damn its great! i saw my strongest girl gain an easy inch in width just during my workday today. amazing.
 
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