Looking for advice

[Pescador]

My main goal in moving my tank to the basement was to have a fish room for all the equipment that goes with it. The main things were a sink close by, ro/di setup and a container for topup and one for water mixing.
For a water change on my setup, it's not automatic but there is no lifting either. I drain the tank into the sink to a mark on the tank equal to the water change barrel (50 gal.) and with the same hose connect it to the mixing pump in the barrel and pump it back to the tank.
The ro/di then fills it up again to mix the next batch. The ro/di also goes to the topup container and the auto topup goes to the sump.

A few things you might also consider:

-Cement board or green board instead of drywall around the tank.
-GFCI's on your 3 circuits. I use a controller and DJ power centers instead of having the outlets switched. You'll be amazed how many plugs you end up using. I'm at about 20.
-A good waterproof paint around the tank. I found an excellent alkyd used in hospitals.

The one thing I couldn't do was the HRV but I'm getting by with a fan and a dehumidifier that is plumbed to the floor drain. Your HRV to your canopy sounds great but you're right the trade off for cool and dry is higher evaporation. Auto top up is a must. (not directly from the ro/di to the sump, right Tony?)