So, I thought I would share my coral/fish QT system. I use a submerged tray system for new coral arrivals. There are three submerged trays sitting in a 180g self contained tank, each with a small pump for flow. The 180 has it's own sump and skimmer and serves either as a coral or fish QT, currently houses an Achilles. There are also separate self contained 150g total volume tanks with dividers on the wall that share a separate sump and skimmer.
The three submerged trays are gravity fed from the DT continuously by a drip system, and they each separately overflow into the sink drain. Therefore, the temperature of the three trays are controlled by the 180g tank, however the chemistries are maintained from the DT. The lighting serves both, the trays and the tank they are submerged in.
This system has several advantages:
1. New arrivals are placed in separate trays to isolate any pests they may have.
2. The coral in the trays are easy to examine, dip, etc.
3. When a tray starts to grow algae, the coral are placed in a vacant tray and I add a half bottle of H202 to the tray, after a few days the tray is algae free, potential pests are oxidized, I simply gravity drain the tray and open the fill valve to refill it, takes just a few minutes.
4. Because the trays receive DT water there is no acclimation necessary when they are transferred to the display tank.
5. Calcium, Alkalinity, Magnesium, ph, salinity, coral food, etc. are provided by the DT. This saves a lot of work and redundancy that would be required doing it all for a separate frag tank.
The ease of use, low maintenance and convenience of this system is far better for coral QT purposes than a "frag" tank, that is just too much trouble, IMO