[Ben_H]

Morning,

Did a quick site search but couldn't find anything so here goes.

I have been composting the waste from my tropical fish tank for the last two years - plants, fish poo, some sand. I don't mix it in with my general compost as I'm uncertain about any toxins building up within the tank system. The compost it makes is very fine and I've just put a load down under a hedge in the garden as mulch but at the moment I'm loath to put it anywhere near fruit and veg or the chickens which will hopefully be arriving in the next fortnight.

Is anyone else on here doing the same? Should I just mix it in with my general compost or should I not be doing it at all? I guess my main concern is the additive that goes in to treat the tap water. I suppose I could always send a sample off somewhere but that's probably an expensive last resort

Cheers

Ben

[8doubles]

Whenever i de sludge the small ponds it goes straight on the raspberry cane bed and they love it.
As you say best to keep it away from fruit and veg that will be eaten raw as warm water and fish poo will be a breeding ground for harmful  bacteria.
I think composted the aquarium waste will be fine.

[Nobbie]

I'd say it would be fine in the main compost bin and will be safe to use on crops. Cow poo is full of bacteria as well and most of us use that without worry. The additive doesn't seem to do the fish any harm, so again I don't see a problem.

[Dominic]

Fish create ammonia.
Bacteria in the tank turn that into Nitrite
Another group opf Bacteria turn that into Nitrate

Nitrate is one of the three base fertilisers, NPK

Not entirely sure what your "composting", yiour weekly 10% water change shouldnt pull out that much solid material.
Anything you do pull out is fine to go straight on plants, perhaps check PH?

I just empty into a bucket and throw in the general direction of plants.
When its dry, I use it to water them.

[Alastair-I]

Not entirely sure what your "composting", yiour weekly 10% water change shouldnt pull out that much solid material.

You've obviously never grown Vallis in an aquarium!  I used to pull out an armful a month (incidentally, it also grows very well in the pond)..

With a freshwater aquarium there shouldn't be a problem putting the old water directly onto the garden.  It's a very weak fertiliser at best, any significant amount of nitrate would be causing detriment to your stock and with a well planted tank it's been my experience that the levels of nitrate in the water you remove from the tank are generally lower than levels in water as it comes out of the tap.

The only possible "toxins" would be any you add specifically to the tank.  If you're using algaecides or medications (particulary copper-based), then I'd flush the next few water changes down the drain just in case.  Small quantities of dechlorinator shouldn't pose a problem - but I must admit that I stopped using it and drastically cut-down on water changes a while ago with no detrimental effect on water quality when I started planting more heavily and stocking more lightly.

[Ben_H]

Not entirely sure what your "composting", yiour weekly 10% water change shouldnt pull out that much solid material.

You've obviously never grown Vallis in an aquarium!  I used to pull out an armful a month (incidentally, it also grows very well in the pond)..

Yes, it's good old Vallis sp. mainly with some annoying duck weed that I cannot get rid of plus monthly clippings from assorted amzon swords and other stuff. This gets composted with the syphonings from the bottom and the newspaper used to cover the floor during the water changes. It's taken me three years to fill the compost bin and I must have put other stuff in with it over time so it's not going to be a huge issue in the future.

I think what potentially worried me most was the tapwater treatment jollop I put in that locks up any heavy metals etc in the water supply and whether over time that would start to accumulate. It's supposed to coat the fish gills in some way that makes them less susceptable to nasties in the water.

Thanks for the help.

[sunshineband]

We put the whole lot stright into the compost bin and it quickly becomes unidentifiable -- aquariul waste including rogue plants, and sludge from the pond from time to time 


and of course tons and tons of duck weed 

[Dominic]

Plant clippings are different
I had visions of you emptying out all your substrate and composting that!

The only way you'd get a lower nitrate reading out of the tap than the tank is if you grow a lot of plants, which of course, appreciate the fertiliser.