New to forum and need some tips

[garagedude]

Hi everyone,
I'm new here and I thought I would say hello and I also have a question. I have an established 20gal hex that I'm going to swap out for a regular 20 gallon tank. The hex has some guppies, mollies, three small Irridescant sharks, and a plecostomus in it. Can I just drain about half the water out of the hex and put it in the 20 gallon, move filter {Fluval 306} and just move the fish? I don't have to re-use the gravel but I could? Would this tank still have to cycle again? Any help would be great.

 

[SiberianSiren]

I did that with my tank, although I would recommend using most of the water. I set up a 45 gallon using RO water and the water from the 20 gallon. I set it up with a new filter but added old filter media from the 20, once the RO water was warm I started adding the water from the 20 gallon, then moved the fish over. Everyone made the transition well. If temp and PH remain the same you shouldn't have any problems, but the tank will still take time to cycle. Just do frequent water changes until it's established.

 

[StevenF]

"Can I just drain about half the water out of the hex and put it in the 20 gallon, move filter {Fluval 306} and just move the fish? I don't have to re-use the gravel but I could? Would this tank still have to cycle again? Any help would be great."

Yes you can but I would check the ammonia levels daily While the filter will have the needed bacteria a new substrate will not and you might get elevated ammonia levels. It would be better if you could transfer all of the gravel from the old tank to the new one.

 

[fishtanksetups]

Yes, you could. I've done it a few times in the past with no fatalities.

Tank would still need to cycle but will not take as long as a fresh cycle. Just change the water until the water parameters are stable.

I would take some old gravel and put it in a mesh bag and let it sit next to your filter (or in it) to harvest bacteria.