Tropical Fish Forum

Tropical Fish Keeping Help and Advice => Fishtank Filtration and Cycling => Topic started by: Chris on March 10, 2015, 09:55:31 PM

Title: Perlite as a filter medium
Post by: Chris on March 10, 2015, 09:55:31 PM
Has anyone tried using Perlite as a filter medium? (yes - Perlite from the local Garden Centre).
I saw a guy recommending it on a You Tube video, stating it keeps the water beautifully clear.
It's an inert material, so does no harm to the fish.
I'm trying it and it is doing a good job so far.
Title: Re: Perlite as a filter medium
Post by: Richard W on March 11, 2015, 07:22:40 AM
I  don't see any reason why not, it has a very large surface area for volume and should hold plenty of bacteria. It's also inert and pretty well sterile.. Sounds like an interesting idea. However, I wonder how you clean it, would probably be more fiddly than sponge. If I were using it I'd put it in a fine mesh bag.
Title: Re: Perlite as a filter medium
Post by: Sue on March 11, 2015, 09:56:17 AM
The fiddliness was my first thought too. I use perlite for my African violets (mix potting compost 2:1 with perlite or vermiculite) and it is very light and fluffy. The only way it could be used, in my opinion, is in a fine mesh bag.
I presume it crumbles quite easily as now I'm getting to the bottom of the bag I'm finding a lot of dust instead of tiny balls of white. This would be my concern about using it as a filter medium - will it crumble to dust when wet, like it does when dry, and slowly disappear especially after cleaning the goo out? I would experiment with some in a bag in a tub of water before putting it in the filter.
Title: Re: Perlite as a filter medium
Post by: Richard W on March 11, 2015, 10:04:56 AM
I guess the other question is whether it has any advantage over more established media.

I buy it in 100 litre bags for making up plant compost. I think that it's less inclined to break down and become dusty when it's wet.
Title: Re: Perlite as a filter medium
Post by: Chris on March 11, 2015, 09:15:12 PM
Some good observations there.
I forgot to mention that I put it in a fine mesh bag before placing it in the filter.
Also, before filling the bag, I washed out the dust and smaller particles with some tank water, through a colander.
The perlite has to go into a bag because it is not very dense and tends to float.