Canister

[boydiscus]

Would a sponge filter be good enough with a discus tank 3ft with gravels ? and If i have a bare tank or gravel tank with a canister that says its suitable for 300 litre tank and i have a 150 litre tank would that stress out my young discus, my discus will be around 5cm

[Carol_Roberts]

You do not want to put small discus in a graveled tank. Your sponge filter will be fine in a 36" bare bottom tank with those small discus. AS the discus grow and produce more waste you may need to add another filter.

I don't like canister filters, but you can use that size on the smaller tank. IF the discus don't like the current aim the water return to the back corner of the tank.