I only have three tanks (1-1 gal, 2- 3.65 gal), but I usually only change my water once a wekk unless my test kits show that my water parameters are changing (ammonia and nitrites going up). Two of my tanks are planted currently The one gallon is a temp home until the other tank cycles. I usually get the water ready the night before and declorinate it so that its ready first thing in the morning then I syphon out the water out into a premeasured container, then pour the new water in. Its a hassel, but I think that the fish really appreciate the clean water.
1 Red Veiltail named Jasper
1 Bluish Purple female Betta named Alice
1 Jack Russell Daschund mix named Russ
1 Border Collie Mix named "Just Jack"
1 21 month old daughter named Ayla
A Betta is like a potato chip, you can't have just one!