Undergravel Filters

[smithyif]

a silly question but can undergravel filters only be used under gravel or can they be used under sand ?

 

[Gilli]

You can only use them with gravel - sand would not work as the air and poo have to be able to drop through the plates. Steer well clear - they are hard work and not very effective!

 

[mbsqw1d]

You can only use them with gravel - sand would not work as the air and poo have to be able to drop through the plates. Steer well clear - they are hard work and not very effective!

agreed ^ ^ ^

they're rubbish!

 

[OldMan47]

A UGF can only be used under gravel. Sand particles will fall through the filter plate and fill the space under the plate. That space is intended to stay free of any material so that it can give you a free flow or water. If set up properly, a UGF can be a very effective filter but it requires you to be aware of the limitations of the technology.