1m 1bout to set 85g tank, i am going with flourite black sand,, my next q regarding filters, i have one eheim classic 2217, am thinking buying another one, or should i consider some other filters like ocean clear, i never use and not sure how to set them, i know i need to buy pump for it, but these filters look quite big? the tank will be for plants and small fishe,(tetras)
anythoughts?
thanks

Not sure about the Eheim filters, but if you only interest in adding an additional filter or improved flow you could just add a pump inline with the outflow of the Filter to improve the the flow from the filter.

I've done this with my Rena XP4. I found the flow deplorable so I added a MagDrive 9.5 and the flow easily tripled. I've found no adverse effects to the biological. Its cheaper than buying another filter just to add flow and it pretty much ensures that your top draw canister will never airlock on you.