because my 4mm base cracked. trust me, when u going for a 1.2m sump and a big dsb, that thing will hold 60kgs of sand easily!
the problem is the length, i.e it tends to compress on the polystyrene in the middle were the dsb is, which causes it to bend and crack. 6mm is safer IMO...
because my 4mm base cracked. trust me, when u going for a 1.2m sump and a big dsb, that thing will hold 60kgs of sand easily!
the problem is the length, i.e it tends to compress on the polystyrene in the middle were the dsb is, which causes it to bend and crack. 6mm is safer IMO...