What is repashy?
I have a common in with my fancies and he does get a little more because he is just faster (and smaller) but they each get more than enough food without having any leftovers.
When I do a water change, the hose is hooked up to the spigot (outside), so I cannot control the temperature. Because of that, I do about 40% water changes every week (minimum) or after a really messy feeding. With 20 degree temps in Colorado, the water temperature difference is too large for 80% water change. I also found a really large canister filter on Craigslist designed for a tank over double the size. The larger and better filtration, the less you have to change the water (as long as there are no large chunks of food sitting on the bottom).