2217 has a real world flow of ~600l/h so yo'd be turning over your tank 7 times an hour or once every 9 min if you were keeping L numbers, they'd love it. but way too high for discus
Hiya, I've just found an Eheim clamp apparatus they use on the inlet pipe to restrict flow variably - it's a genuine Eheim part so you'd be able to turn the 2217 right down (I've got one on a 4' & it packs a huge punch) until it starts to fill with gunk again & flow drops a bit. I've ordered mine here: http://www.discusforums.com/forum/vi...=162532#162532
I would've said the same thing, but this part is manufactured by Eheim, for Eheim so therefore I would put my faith & trust in them knowing precisely what they're doing