I have a 30 gallon oceanic cube with a HOB
filter and a DIY canister filter with adjustable flow (overkill for the tank). Fish in that tank are healthy and happy.
I just bought a 10 gallon tetra half moon tank off of craigslist for $10. The filter on it is a whisper 10I in tank filter, and it's pretty pathetic.
My question....would it be possible to use my canister filter on both tanks? And if I do so, will the new tank be instantly cycled? Will it hurt the residents of my current tank to do so? My husband (who built the canister filter) can run the filter to both tanks without too much trouble.