Tank change

[PGriff]

I'm building a new bigger better tank stand. I'm buying two new tanks to mock it up and when it's done I'm going to switch everything over.

I'm changing the substrate from sand to crushed shells but the 40 lbs of rock work will go into the new tank.

My question is about cycling. When I transfer the fish if I save around 80% of the water in a temp bucket while I'm setting things up and use the original rock work when it's done. Then put the same 80% water back in and top it off would I have to recycle the tank?

 

[ThePurple12]

No, because the bacteria from your previous tank’s rocks would still be there.

 

[ThePurple12]

Make sure to add any new fish slowly, though

 

[Fish4udog]

No need to cycle, I had a 75 gal went to a 120 gal tank took 30 gal brut trash cans put my original tank water into 2 separate trash cans 1 for rock & coral the other just for the fish, I made all new water but 20% put new sand filled tank added rock back in then the coral topped off with old water added fish back in. Did not lose any coral or fish could hardly tell I switched tanks everything looked just like it did before the move. Used same sump and filtration equipment

 

[ThePurple12]

Same here. I just upgraded from 75 to 125. I used 100% of old tank’s water, including sump, and the rest was new. I added all of my old rock and sand to new tank, then I added fish and coral once the water was warm enough.

I did the same thing when upgrading from 30 to 75. Everything was fine.

 

[PGriff]

No need to cycle, I had a 75 gal went to a 120 gal tank took 30 gal brut trash cans put my original tank water into 2 separate trash cans 1 for rock & coral the other just for the fish, I made all new water but 20% put new sand filled tank added rock back in then the coral topped off with old water added fish back in. Did not lose any coral or fish could hardly tell I switched tanks everything looked just like it did before the move. Used same sump and filtration equipment

That's almost exactly what I had planned on doing. I didn't think I would have to but wasn't sure how much of the old water I would have to save.

Thanks