Can bio balls be completley under water?

[jamal-188]

I made a wet/dry out of a 15 gallon high aquarium for my new tank today. Can the bioballs be submersed under water or does the water have to drip/run over them?

Thanks everyone!

 

[stresco]

They have to be exposed to the air.

 

[reefrunner69]

To be the most efficient, they should not be submerged, but will work completely submerged.

 

[gooyferret]

I have heard of taking the bio-balls and if they are underwater to use an airline and cheap air pump and wood stone to accumulate the air movement under the bioballs. HTH This should help with micro algae.