Re: My First Grow Journal-Holy Grail Kush- Purple Kush 6x12 Scrog 4 x 600W LEDs On Mo
Hi Jon -
I think you nailed it, in that they are drinking much more water than consuming nutrients causing the PH to sink. The question is why...
Are your temps abnormally high, or your RH abnormally low (at plant level especially)? Personally, I would
think your reservoir is big enough, though this behavior is proving that a larger reservoir might be easier to manage at times, and size of your plants might play into that as well.
Also, your nutrient mix might be too hot - especially if they are drinking so much more water than they are consuming nutrients. Have you been monitoring PPM's? If so, what are they doing - are they higher also when PH goes down? (I'll be surprised if not). I'd seriously consider how hot your nutrient mix is, as this may be part of the problem too.
Finally, some things like root problems/pithium can cause PH drops, but they seem so healthy that I doubt this is in play.
When it comes to PH in a nutrient reservoir, typically:
EC/PPM's up, PH down = use less nutes
EC/PPM's down, PH up = use more nutes
EC/PPM's stable, PH up = ideal
Not sure if it's possible with your set-up, but would it be possible to put a "float valve" on your reservoir connected to a water source somehow? I don't use it this way, but if I needed to, I could connect my water to my reservoir directly (via my RO system), and it would only replenish when water depleted (so it never overfills, nor would the level ever decrease). Obviously, this dosen't address the "cause", but you would be less likely to be burned by it.
That's what comes to mind for me... hope you get it figured out! Your plants seem really healthy though, so I wouldn't panic (not that you are...)