Advice for changing substrate

jace_da_face

So I’ve decided I want to change out the substrate in a mature tank - Juwel Trigon 190. It has a compost bed, covered in a sand substrate. I want to take out the sand and replace with a gravel - more of a grit really.

So I want to do this on a live tank with minimum disruption to the inhabitants and to the filtration and tank stability. I would be confident that I could scoop out the sand in one afternoon reasonably ok. I wouldn’t imagine it necessary to remove every grain of sand as this would likely disturb the compost bed. But some cloudiness will likely be unavoidable.

My concern would be that the removal of the sand substrate would likely remove a lot of helpful bacteria and thereby affecting water chemistry and reducing filtration.

So the question is do I do this all in one go or do I do it in stages, i.e. remove the sand and replace section by section over the coarse of a week or so? Any advice is welcome.

Berserker

Changed the substrate in my 180L a few months back and I did it in one go. Moved the fish into my spare tank for the duration of the change. My tank is mature, just like yours and I had no issues with the water or the stability of the tank afterwards. I did soak the new gravel in tank water before I put it into the tank. Given that you are leaving the compost bed in place, I can't see you having any issues.

Duane Dibbley

I wouldnt go scooping the sand out, I think you would be better off getting a length of hose and syphoning the layer of sand out which will do a water change at the same time.

This way you can start at one end of the tank and do it in grids replacing the syphoned sand with gravel as you finish a grid.