thanks for your cooperation much appreciated. i only just switched from a hob to canister 1 day ago and suprisingly the tang was acting perfectly fine before switching with no signs of any of this. the water is in a good range at salt 1:023 ammonia 0 nitrate 10 nitrite 0 and ph 8.3. i beleive that nuisance algae is seawedd i fed earlier and has not been eaten. would u recommend me switching back to the hob filter then?