Maintenance while molting

My PP is currently molting. I removed my E from the 10 gallon into a 40 gallon and planning to move my PP to the 40 gallon when he resurfaces. But… my PP tank is not in great conditions. I think I may have flooded the substrate, because there is mold growing. I’m wondering how to I maintain this tank and not disturb his molt. There is only about 3 inches of substrate currently as well. Any tips would be appreciated!