I have one used Eheim filter available in good condition and working order.
It was used on my 32 gallons tank, but in the description they say it could work to about 66 gallons,. I think this filter is best used for tanks up to 40-50 gallons is it is better to have more filtration to keep water clean. Also in depends on the number of fish you keep.
I still have some used ceramic cylinders (filter media), which I can give to you. They are still OK to be used in this filter.
If you are interested, please PM me or call at 905-434-3753. Thank you.