DNA Golden Berry Sativa Dom. Scrog 1400w HPS/LED day 40 flower onwards

Hi,

DNA golden berry sativa dom - My other is clearly indica dom.
canna aqua flores
ec 1.6
ph 5.9
1000w aircooled hood
2 x 180w generic leds that seem to work
22-24c day time 12-16c night time
20< RH%

Day 40 of flower counting from the light cycle change. (31 day veg) Apologies for the HPS.....

So my question is two parts.

A. Is it best to top up my reservoir at night before lights out or in the morning at lights on? Or it means F all?

B. Does anyone have experience with how cold the charged air you push into your air cooled hood has on bulb efficiency? I have very cool charged air and can run my hood 10 inches from my canopy at 78 degrees MAX MAX. But I've heard you lose efficiency when you cool too much.

Do you think Ive surpassed the point of "best" efficiency for light distance vs heat?

Anyone? It really makes a diff if i cool it down. I can gain 4 inches.. But at what point have a reached the point of diminishing returns. hmmm