Hi all Found an old filter and decided to fill it with something and throw it in the tank, Just wondering whats the best media for polishing water that wont cost the earth please? thanks

Probably one of the cheapest options would be air-conditioning wool, in that you can buy a large amount for a good price. It would require regular replacing though.

Is the filter going to be in the tank long term or do only have plans to use it when you want to clear up the water (say if you want to take some photos etc).

Also what sort of filter is it? Internal power/HOB/canister?

Other than that, sheets of fine filter sponge will do a good job at polishing the water. Keep in mind the finer the media the quicker it will clog up with debris.

aus-car wrote:


if this is the white filter cotton wool ,aus is referring to, that's the best in my opinion.
i only use it as the top layer of my pre filter, and it needs to be replaced weekly.
But it cleans any big debris out of the prefilter and sump, and it works like a charm.