I've never liked the bare bottom QT look, and have noticed how some fish seem uncomfortable in that environment. Especially sand burrowing wrasses, gobies and other fish who utilize sand as part of their daily routine. I've also seen tangs, angels, etc. fight their reflection on the bottom glass.
So, I decided to experiment with some sand in one of my 40 gallon QTs (pic below). I used this 10 lb bag of aragonite, just enough to cover the bottom: https://www.petco.com/shop/en/petco...el-substrate/caribsea-aragonite-aquarium-sand
I chose aragonite because it is coarse, and thus unlikely to stick to a fish's mucous coat or inside the gills. This is a concern because parasite tomonts can encyst to sand, and you don't want to transfer any of those into your DT or a holding tank. I tested the copper level daily (for absorption) using the Hanna High Range Copper Colorimeter (HI702). To my surprise, 10 lbs of aragonite only absorbed ~ 0.20 ppm worth of chelated copper (Copper Power). That is easily manageable so long as you test your copper level on a regular basis!
The QT looks better, the fish seem calmer/more comfortable... especially the Yellow Coris Wrasse and Diamond Goby in the tank. So, go ahead and use sand in QT!
So, I decided to experiment with some sand in one of my 40 gallon QTs (pic below). I used this 10 lb bag of aragonite, just enough to cover the bottom: https://www.petco.com/shop/en/petco...el-substrate/caribsea-aragonite-aquarium-sand
I chose aragonite because it is coarse, and thus unlikely to stick to a fish's mucous coat or inside the gills. This is a concern because parasite tomonts can encyst to sand, and you don't want to transfer any of those into your DT or a holding tank. I tested the copper level daily (for absorption) using the Hanna High Range Copper Colorimeter (HI702). To my surprise, 10 lbs of aragonite only absorbed ~ 0.20 ppm worth of chelated copper (Copper Power). That is easily manageable so long as you test your copper level on a regular basis!
The QT looks better, the fish seem calmer/more comfortable... especially the Yellow Coris Wrasse and Diamond Goby in the tank. So, go ahead and use sand in QT!