That was to keep the males separated, you don't need large volumes of water with lots of oxygen in it, they take half their oxygen from the surface air.

Three tanks!
How often do you have to do water changes?

I keep a tank of fancy goldfish - oranda, black moor. I've had a platy for cleaning the gravel for a while but lost him a few months back. Waiting for the fish man to get some more in, he sells more tropicals than cold.

50% water change every 8 weeks, I have external power filters that pump 300 gallons an hour through them, so every drop of water in the tanks gets "scrubbed" 10 times every hour.

Wow! Might have to look into more up to date filters then.
We have to do a 25% change every week, and we have two internal fluval filters. I feel a chat coming on in the fish shop on Monday