Ok I can't find anything to help me. Maybe I'm frustrated or just need to smoke idk. Quick run down 8" big mama blocks pre soaked for 24 hours at 5.5. I'm hand watering to waste 4 weeks into bloom run off ph is high and ec is lower by about half 840 going in 420-560 coming out. If I'm correct the low ec is causing the higher ph runoff. My question is to correct the ph of the block do I A: water with higher ec at 5.5 in normal amounts? B: run a lot/flush of 5.5ph thru it with a higher ec? Or C: lower the ph of my nutrient solution to say 5.0-5.2 to correct it?
1st off 5.5 PH is not good for pot. You want 5.8 for a more efficient uptake of nutes. The losing half of your PPM part is a total mystery to me, as usually the PPM will increase over time, not go down. This is what I do, though I run a recirculating drip system. Use a PH of 5.8 and run it through with a PPM of 1000 at 4 weeks bloom. I run my seedlings at around 650-750 with no problems. Mid veg I have bumped it to around 1300 PPM which I keep untill the final 2 weeks of bloom, and then I stop adding nutes and begin my flush that way.
So, for ease of measurement, start with a PPM of 1000 and a PH of 6. Test runoff for the PH (forget PPM for now) If your runoff is higher than what you put in, reduce your PH at the next watering. If it is low, increase your PPM to compensate. Example- PH going in is 5.8, and the out is 5.6. Increase the next watering to 6.0, counting on the rockwool to bring it down. That way you count on the drift of the PH to bring you through the target zone, which in hydro is 5.8. A little high is no big deal, but low diminishes the ability of the plant to take up nutes, and can cause lockouts, the same as having too high a PH (6.5 and above) Don't sweat the PPM now, as you would want to start reducing it now anyway I hope I have helped, and good luck
