Hey sweetleaf,
I hope the chiller turns out to be necessary, either way nice to have control.
I find that DO is better at lower temps (i.e 68*) but bacteria grows a bit faster at higher temps (i.e. 72*)
DO really helps the plants and combats anaerobic bacteria. I have done some testing and with my airstones I am able to get the DO to about 150% or about 15mL/L range. That is great for BB and plants. So if you really want to tweak this, my results would guide a higher initial temp in the res when first starting because small plants don't use as much O2 and building that colony fast will fight root rot. Then after the colony is fully established, you can bring the temps down with the chiller to the 68 - 70 range for best plant performance.
If you do it right, here is what you have to look forward to:
View attachment 1257127
Root mass is approx equal to bud mass, or at least they correlate. So this would be a "big" harvest situation if that is your goal.
EDIT: I keep hearing that nutes satin roots. Not true. H2O2 damages root tissue for the sterile guys, and they interpret that as micros staining. No staining there and these have been fed a full diet sans H2O2.
EDIT EDIT: That gap between the bottom of the net pot and where the root mass starts is the distance below the pot where the water line sits. Hopefully you were able to get yours adjusted down a bit.