Using dirty filter silt/sediment as fertilizer.

[I MACDONALD]

Although this might seem a bit off piste bear with me. I've been using filter silt/sediment as a plant fertilizer for a while now and last year had beautiful results from my outdoor container plants. I also used old tank water to do most of my watering and we had 15 ft sunflowers growing in tiny potato bags at the back of our house in the Isle of Lewis. What I was wondering is if anyone has attempted to re-use it in an aquarium? I realise to most people the amount of silt they get from their filters would scarcely fill a teacup but I was surprised how much I got from 2 Fluval 405 and 3 Eheim Aquaballs. Obviously it would just clog up the filter if you just dumped it back in the tank but I took to pouring the dirty water that I cleaned the sponges in, on top of the various containers and once it had dried up there was a surprising amount. I just thought if I filtered it (I know it sounds crazy) and dried the remaining sludge would it make a good first layer and if anyone had tried it before.

 

[rodley]

I have seen mulm used in El Natural/Walstad tanks. Adds some slow release fertilisers and microbes to the substrates used above it.