turning sump to refuigium

[mason]

hey all i currently have a sump with the bio filter material and im going to turn it into a refugium. my lfs told me to take half the material out of the sump then the rest of it a week later.. i did in fact take about 1/4 of it out today n now im wonrdering if that will affect my tank in anyway and is that the right way to slowly go about turning it that way. if its not right i do have the material in a bag n willl put it back in if i can n need to.. all the advice i can get would be greatly appreciated ty

 

[David S]

what do you have in your tank? LR?

 

[BigJim]

When you remove biomedia, you're removing nitrifying bacteria. If you remove too much too fast, you'll put your tank through a cycle.