@billyocean I had a similar issue with high levels of tin about a yr ago.
Is you friend feeding frozen foods? Is he rinsing it before feeding it?
I had bought (I forgot the brand) of frozen cubes and it said on the package no need to rinse. Well I used to pop the cube and just drop it in the tank and go to work.
One day I decided to move some of the rock structure around and that's when I found a piece of the tin foil that seals the cubes in the package wedged under one of the rocks.
After couple of big WC, I was able to bring the levels down.
Is you friend feeding frozen foods? Is he rinsing it before feeding it?
I had bought (I forgot the brand) of frozen cubes and it said on the package no need to rinse. Well I used to pop the cube and just drop it in the tank and go to work.
One day I decided to move some of the rock structure around and that's when I found a piece of the tin foil that seals the cubes in the package wedged under one of the rocks.
After couple of big WC, I was able to bring the levels down.