I've gotten the chance to use an Eheim pro, though I think the one I worked with didn't have the "digital thermal display." It doesn't stand up to its predecessors, the Classic 2260 or 2262 for several reasons.
The bells included in the Pro just aren't that great. The wheels aren't useful. The primer isn't anything any pro I know actually needs. The flow meter is a who cares. If you're concerned about the flow on your canister filter, you're just not maintaining it properly. You don't need a meter to tell you that you haven't cleaned your filter in a year.
I also find that the media baskets are useless. They just restrict what you can fit into the filter. The Classics are more flexible.
My biggest issue was that (unlike the large Classic Ehiems) the Pro doesn't have a water outlet at the bottom. This is an essential tool for easily maintaining the canister. Otherwise, taking the top off can be messy.
Here's something I've found in my experience: real professionals stick with simple, functional, well-built tools. The ehiem classics are industry standard and no canisters match them for longevity, simplicity, and ease of use. Even Eheim's own Pro series don't hold a candle to their Classics.
Lastly, any of these seem like a lot for a 50 gallon. I'd personally go with two Ehiem 2217s You'll find they do the job well and will be easier to handle and work with.
The bells included in the Pro just aren't that great. The wheels aren't useful. The primer isn't anything any pro I know actually needs. The flow meter is a who cares. If you're concerned about the flow on your canister filter, you're just not maintaining it properly. You don't need a meter to tell you that you haven't cleaned your filter in a year.
I also find that the media baskets are useless. They just restrict what you can fit into the filter. The Classics are more flexible.
My biggest issue was that (unlike the large Classic Ehiems) the Pro doesn't have a water outlet at the bottom. This is an essential tool for easily maintaining the canister. Otherwise, taking the top off can be messy.
Here's something I've found in my experience: real professionals stick with simple, functional, well-built tools. The ehiem classics are industry standard and no canisters match them for longevity, simplicity, and ease of use. Even Eheim's own Pro series don't hold a candle to their Classics.
Lastly, any of these seem like a lot for a 50 gallon. I'd personally go with two Ehiem 2217s You'll find they do the job well and will be easier to handle and work with.