ph out of control

[bodean614]

i have 2 hydrofarms with 430 hps
using GH 3 part nutes mixed at 900ppm
i start with ph at 5.2 - 5.5 but in 1 day it jumps to 6.5 - 6.9
plants have been vegin for 3 weeks without any growth
they seem to have gotten bushy but no real growth
leaves seem to curl a little and some yellowing .. res. temp should be at ????
any thoughts

 

[MTF-Sandman]

Sounds like root rot or severe underfeeding. Res temps should be in the upper 60's...mid 70's at the most, but IME anything over 75 is asking for root rot.

 

[bodean614]

i fugured thats what it is..
thanks man

 

[Brian1975]

I was told that closer to 60 is better for optimal oxygen distribution/uptake.

 

[MTF-Sandman]

It is for O2 holding ability, but the amount of O2 that's required for healthy roots is pretty low (like <10ppm) so if you go too cool, it'll slow down the plants ability to uptake nutes. There's a thread or two by folks who have DO meters and I wanna say the difference between 70f and 60f was only 1 or 2 ppm

 

[bodean614]

so is there any saving them or just trash and start over

 

[MTF-Sandman]

I'd be hesitant to tell you to scrap them without the full details of the setup and some pics of the plants. Besides, starting a new grow in a bad environment will just lead to problems on the new crop.

 

[bodean614]

i scrapped them and figure my res temps where to high. hydrofarm buckets only hold 2 gallon so dont take much to heat up. i will get a 10 gallon control res. and do the old frozen 2 liter bottle trick to keep temp steady. just new to hydro and getting the quirks figured out now.