hiya don't often post but i get all my info by reading the excellent info posted on the forum.just a quickie. my tank at the moment seems to be running ok (must get some photos on).i have a trigon 190 planted aquarium the tank contains 12 copper harlequins 10 cardinal tetra 3 ottos 4 corys im thinking of getting a couple of small discus but im little worried about the 50% weekly water changes will this put the discs under any stress or will they be able to handle this. all my water parameters are ok using ei method ph 6.8 nitrates 0 thanks for any replies.