"SkyCatcher" wrote in message
...
Hi,

I hope I'm not being dim but if I have a 600 litre tank can I use 2 x 300
litre rated external filters on it? If so should these be run in parallel
(i.e. independantly) or in series(i.e. linked together).

tia,

Sky



Using two filters is much better than one. When you clean one, you leave the
other one alone with the nitrifying bacteria colony. This way, you never
really wipe the good bacteria from your filters. 2x300 should be fine, just
dont use charcoal, or if you use it, change it religiously.