Sorry about the confusion
I'll try to explain it better.
I have 3 filters and tanks running right now.
20 gallon- New tank and new filter.(No Fish)
-Outside style filter that takes inserts (model 30)
Discription of inserts: pre-measured mesh bags of filter media that come in different sizes, depending on the size of the filter.
5 gallon- Old tank and old filter.(Guppies+Corys)
- Same as new filter on the 20g, only smaller (model 20)
3.5 gallon- Old tank and old filter.(1 Goldfish)
- Small internal filter that takes a flat rectangular cartridge
which only has carbon inside of it.
We were talking about moving the Bio-Max from the 5 gallon to the 20 gallon. Then I asked if that would mess up the cycle on the 5 gallon which im planning on moving my goldfish to. You said that it would mess it up and asked me if the filter media from the 3.5 goldfish tank could be moved to the 5 gallon. Unfortunately it cant.
My Idea, was to add an extra mesh bag of bio-max to the filter on the 5g tank underneath the older mesh bag of bio-max. I was wondering if the new bag, will cycle itself, if it is put under the old, cycled bag. I could leave it there to cycle and then move one of the mesh bags to the 20g and leave the other one in the 5g for my gold fish. Im thinking of discarding the filter from the 3.5g because it's in bad shape.
I hope I did a better job of describing things. Let me know.
Thanks for your help and patience.