The drums hold 40 percent, of the aquariums capacity. I can isolate, drain and refill, I can water change, from the basement.
They support two 75 gallons tanks, each on a closed loop, of about. 50 gpu, through the drums, they also cool the tanks about 10 degrees.
It takes 15 minutes to fill, 30 minutes to drain. So basically I just open and close valves. To do a water change.
The tank has minimal substrate, and engineered flow, with an air lift, installed in a dead spot, to lift any heavy solids, into the sump.