# Quick question about bio balls



## BHeidemann (Feb 14, 2008)

I've been noticing that when bio balls have been used in a sump tank that they are always suspended above the water line and the water flows through them. I've never seen the balls submersed in water. Is there any reason for that?

I am curios because I recently received a brand new Fluval 404 & a 403 and was thinking about filling the tub with Bio balls instead of the filter elements that come with them. Sounds weird but its all put of the master plan.

What do you think?


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## SueM (Jan 23, 2004)

They can be used either way, in a wet/dry system or fully submerged. They are just a surface for the bio to grow.


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## CollegeReefer (Sep 1, 2006)

I personally am not a fan of bio balls, your best bet is to use liverock rubble.


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## BHeidemann (Feb 14, 2008)

CollegeReefer said:


> I personally am not a fan of bio balls, your best bet is to use liverock rubble.


That's what I've been hearing.

I have an 80 gallon tank I am building out now so my plan was to take my old 20 gal tank and turn it into a sump. Would I be ok if I used live rock/sand in the main tank and just put a filter sock/protein filter and heater in the sump?


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## Fishfirst (Jan 24, 2005)

short answer: yes!


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