white smuts

[mcgreg]

Hello,i dont know what im making wrong but now i have white smuts on the top of the water,they are swimming on the water like oil! Can it be that the filter makes the mistake because it dont shakes very well the top of the water?

[Apistomaster]

Hi mcgregg,
Describe you filter and nature of you discus aquarium.
Do you use a canister filter running in a mode that does not agitate and aerate the surface film?
Have you tried adding an air stone?
Is your tank new?
Is it bare style or planted?
Are the discus eating all their food?

[mcgreg]

hi,the external filter is with sponges and substrat(stones),i dont know what airstones are but i think you mean the white stones which i have in my filter,the tank is not new it is about 1 year old,it is planted,the discus does not eat all their food,i use and external filter but i dont know what a canister filter is, the surface film agitate but no as well enough i think.