Yes especially if your tank is under heavy load...!! From my point of view, a mechanical bio filter is better in providing a consistent and
reliable filteration over a natural bio filter.

This type of filteration is categorized as wet dry or trickle filter...wet dry does releases Co2 but is not very significant if the filter system
is setup properly.I'll still need to do some testing on rate of co2 loss with different setup in the future and see how long my 10kg Co2 tank will lasts (first time was 4 days only due to mishandling...had to forked out another RM37 for refill)

Few types of filter media (coarse and fine)are utilized with 300 Bio balls.
This is sort of my pilot project. So everything installed or setup are on trial and error basis..!!

Hey Roadspike, how do you setup your return piping from the filter up to the tank??

By the way, any good suggestion on sustaining water temp below 26Cel..??

Robby