Will replacing my gravel to sand harm my tank

[daft]

My tank is cycled I have one pea puffer. If I replace my gravel with sand will it harm my tank and mess up the bacteria that was living on it.

[nabokovfan87]

Hello @daft welcome to the forums! 🙂

I have replaced substrate many times and you should have a reliable filtration in place to avoid any issues.  Things like hardscape, filtration, and the tank glass will all house bacteria in addition to the substrate.  I have probably changed substrate something like 10-15 times and I have never crashed a tank when doing so. 

Let's focus moreso on your filtration setup, then I can be more confident in saying yes or no to the question though.  Can you share some details on the setup and how the filter itself is setup as well?

[Chick-In-Of-TheSea]

 I did a 2" sand cap on top of my gravel. I left the gravel dirty so the plant roots can reach down and utilize that stuff as fertilizer. It worked well.  The gravel allows the plant roots to spread out nicely.  I used the mess free method to do this. It prevents dust in the water column.  I do rinse the sand in the bottle first, and pour off the water, several times before adding to the tank.

 

Edited August 25 by Chick-In-Of-TheSea

[Guppysnail]

As long as you have other filtration and don’t over clean the rest of the tank while switching you will be fine. I’ve done so many times.

I’m currently changing over both of my fishrooms from UGF/gravel to just sand.  I do have other filters that run on the tanks. I have had zero issues with any of them. 

Enjoy your project I hope you share before and after photos with us. 

[daft]

I have a sponge filter for a ten gall

[nabokovfan87]

I would think everything is ok as long as the sponge has been cycled and it stays wet/aerated.