Replacing Substrate on Established Aquarium

[Ozzie Boss]

As the title suggests, I want to replace my old sand bed with fluval stratum. The thing is, my tank has been established for 2 years. How does one change the substrate without messing with the fish and beneficial bacteria? Should I put the fish in a bucket when changing the substrate? Thanks for the help.

 

[BlueJungle]

I have changed my substrate many times, both with the fish in the tank, and removing them. I have never had a problem with the cycle after changing my substrate as most of the nitrifying bacteria live in the filter, stuck to the media.

As you are changing to stratum it might be best to remove the fish and keep them in a bucket filled with tank water. And probably best to monitor the water parameters for a while afterwards as stratum can lower pH, and your pH is not well buffered so maybe prone to dropping more than most.

 

[Dephea]

I did the change too. I moved the fish to a big plexi with tank water, heater, little air pump and even some loose plants. I was changing from small gravel to fine sand so I was wiping the entire tank out, cleaned the glass, covers - everything. The only thing I did not clean was the filter. Once everything was in I re-filled the tank with the tank water and only added about 30% of fresh water (150L tank in total). Did not have any spikes, all went well. I did monitor the tank after and I only cleaned the filter about 2 weeks after I changed the substrate.