How long to wait?

[Mike62]

So I decided to get serious about my cichlid tank, and put in a new substrate. I cleaned out all the old little coloured rocks (yes, I know they are wrong, but my son liked the colors) and put in a new argonite sand bed. My question is, after I add the water, how long do I have to wait before the cichlids can return to the tank? Im hoping its a matter of hours and not days, because they are in pots all around the room.

[Lurch1]

I hop other chime in as I am by no means knowledgeable, but I always have advice . Did you keep the same water and filter media? If so I would add them back whenever and watch your tank for a mini-cycle. If it starts to cycle keep up with prime and water changes. If you started brand new everything then I still think the tank is better then pots, you will just have to cycle your tank with your fish and hopefully you can score some old media for the filter.

[Mike62]

I kept the old media filters but the water is going to be new.

[bizfromqc]

The majority of your nitrifying bacteria will be in the filter media, substrate and plants/decorations.

You kept the same filter and media so that's good but you removed a good bunch of beneficial bacteria when you swapped out the substrate. If you are putting the same bio-load (fish) back into the tank with half of the good bacteria, the tank will most likely undergo a mini-cycle.

In a perfect world, you wouldn't add all the fish back into the tank at once but do it over a longer period of time to allow the nitrifying bacteria to reproduce and adjust to the bio-load. But you may only have the one tank and that's not an option.

As was mentioned, keep an eye on the water parameters and be religious with your WCs.

[exv152]

So I decided to get serious about my cichlid tank, and put in a new substrate. I cleaned out all the old little coloured rocks (yes, I know they are wrong, but my son liked the colors) and put in a new argonite sand bed. My question is, after I add the water, how long do I have to wait before the cichlids can return to the tank? Im hoping its a matter of hours and not days, because they are in pots all around the room.

In a very heavily planted tank you may be able to get away with it because the plants absorb some of the bad stuff, but if you're talking a plantless tank, you'll be restarting at least some the tank's cycle for sure.