After speaking with a friend I got rid of the sumps for my QT tanks. Instead of setting up a true coral and fish QT I will be doing the following. For fish I will fresh water dip them all. I will then place them in the 75G QT tank which will be set up on a peristaltic pump off the main system. The QT tank will have an overflow that going into the sewer. This will acclimate the fish to the systems water while I watch them for a few weeks. It also means I don’t have to worry about any filtration, heating or any other parameters in a QT tank. I just set the peristaltic pump up and adjust the drip faster or slower depending on my needs. This will save me money on equipment, save space in the shed, and save $ on power. The only parts I will need for the QT is the peristaltic pump, a light and a power head.
The coral QT (20G) will basically be the same setup. I will dip and inspect all incoming corals and then use the QT to watch them for 4 or so weeks before they go into the display. By then they will be acclimated to my water and good to go. Only items needed to set this system is a light, power head and the peristaltic pump.
This system will slowly lower the level in my main system as well as my skimmer running super wet connected to the sewer. My ATO will be connected to saltwater so the more tank water that goes down the sewer via the QT's or skimmer is just a bigger water change. I will measure my salinity and set up a peristaltic pump with fresh water to keep salinity stable due to evaporation. I don’t ever plan on doing water changes due to the fact that the system will always be changing its own.