I had a good idea the other day (it does happen).

If your like me, and made your tank before you really new anything about what you were doing, you might have gone for a pure sand/gravel substrate.. and then regretted it later on when you wish youd used something richer.

Well I had this idea, of how to get some aquatic compost into your sand, without creating a god awful mess all over the place in the process.


1) Make a thick gooey mud with the compost/whatever you wanna use.

2) Get a freezer icecube tray, and fill each section with the gooey mud, and pack it down, pretty hard.

3) Scrape off the excess from the top of the tray.

4) Turn out the tray onto a baking tray, might need some tapping to get it out, although I found the filling was heavy enough to just fall out of mine.

5) Bake the tray in the oven on a lowish heat for about 30 - 40 minutes. This will dry out each little square and set it rock hard.

6) Then all you need to do is push each nice little brick of solid compost into the sand/gravel. You need to be pretty speedy, as it will 'melt' very quickly.


and job done. This worked reallllly well for me, and because each brick is hard when it goes through the water, hardly any sediment is created.. therefore keeping the nutrients inside the brick as it goes through the water.

Be careful what you use though, if your a garden soil fan, boil the hell out of it first. Although I suspect a long slow bake in the oven will steralise it as wel.