WoW... man that's a bummer...
how fast will your ladies drink half the AGs res?
I have mine as you've seen and I refill about 20 oz a day... 5 weeks in...
Everything can cause a fluctuation of PH and PPM (parts per million)...
There is a formula that describes what happens with the nutes ...
The right size container for the plants you have will not fluctuate PPM as your plants drink
Too small a container and the PPm will go up as they drink
too big and it will go down...
Something like that, I am not sure ...
And I can only imagine that the Ph will vary greatly as more or less of different substances are present in the water...
I don't know what to say... my ladies are small and even then I wish I had more room for their roots.... the kinda just coil around and can't really grow too much without running into something... a deeper container would be good...
I wonder if you can take the top off of the res and rig it to a rubbermaid container...???
That would give you more room for sure... but ... so much for the AG... lol...
I would consider that route man... bigger res should be more stable too... less fluctuation, as a much smaller percentage of the total is consumed/evaporated....
Humm... am I giving you bad advice???? I really hope that if you do decide to follow what I am saying, that you at least run it by some of the more experienced growers here... Ie. Al B Fuct....
Ask man, it can't hurt... be ready for anti AG comments, but HE WILL HELP YOUR PLANTS....
I really hope this helps, or that you find a solution ASAP...
Good Luck Bro...
Gypsy...