I've now been the owner of an Eheim 2074 for around 3 months now so I thought I would give some feedback in case anyone is thinking of purchasing a Pro 3e.
The 2074 is on my 75 and is the smallest of the e models. It replaced a fluval 404, 304 and 2 Koralias. It's rated at 395 gph and holds somewhere around 1.5 g of media with 3 media baskets and a smaller prefilter basket. Of course we know real world flow and rated flow usually isn't that close. That being said, I've been very happy with the circulation it has provided. I think a lot of that is due to installing a set of lily pipes and the placement of those pipes. I have a good circular flow pattern and no apparent dead spots.
Being an e model, I guess something everyone might like to know about are the electronic features - variable flow, constant flow, etc. Well, after a couple of months, I switched it off and went to manual mode. One of the features is that it is supposed to maintain the same output by ramping up the pump as the filter gets dirty. It does this but you never get the maximum flow it is capable of since it has to keep something in reserve to maintain the flow you've selected. Putting the filter in manual mode has given me more output than I was able to get in auto mode even when selecting the highest flow setting.
Another issue I had was with bypass. A couple of weeks after changing over to the Eheim I noticed my water was hazy, when with the fluvals it had always been crystal clear. I assumed the change over had affected the biofilter and attributed the hazy water to that. After 2 months I still had hazy water so I did a search and found a thread on Monsterfishkeepers dealing with the same topic. The OP had the same issue so he put floss in the gap between the top basket and the walls of the canister and it cleared his water. So I tried it and next day I'm back to crystal clear water. It's not hard to do but it seems to be something you shouldn't need to do.
As far as positives, it's quiet, leak free, so far, and easy to service.
Would I recommend one? Not the e model, to me the electronic features turned out to be a nuisance. Buy the less expensive non e models if you want a Pro 3. Of course I didn't buy it for the electronics. I bought it because it had the most output of any Eheim I thought I could easily fit in my cabinet. For the most part I'm happy with it. I was able to get a lot of stuff out of the tank and from under my tank.
The 2074 is on my 75 and is the smallest of the e models. It replaced a fluval 404, 304 and 2 Koralias. It's rated at 395 gph and holds somewhere around 1.5 g of media with 3 media baskets and a smaller prefilter basket. Of course we know real world flow and rated flow usually isn't that close. That being said, I've been very happy with the circulation it has provided. I think a lot of that is due to installing a set of lily pipes and the placement of those pipes. I have a good circular flow pattern and no apparent dead spots.
Being an e model, I guess something everyone might like to know about are the electronic features - variable flow, constant flow, etc. Well, after a couple of months, I switched it off and went to manual mode. One of the features is that it is supposed to maintain the same output by ramping up the pump as the filter gets dirty. It does this but you never get the maximum flow it is capable of since it has to keep something in reserve to maintain the flow you've selected. Putting the filter in manual mode has given me more output than I was able to get in auto mode even when selecting the highest flow setting.
Another issue I had was with bypass. A couple of weeks after changing over to the Eheim I noticed my water was hazy, when with the fluvals it had always been crystal clear. I assumed the change over had affected the biofilter and attributed the hazy water to that. After 2 months I still had hazy water so I did a search and found a thread on Monsterfishkeepers dealing with the same topic. The OP had the same issue so he put floss in the gap between the top basket and the walls of the canister and it cleared his water. So I tried it and next day I'm back to crystal clear water. It's not hard to do but it seems to be something you shouldn't need to do.
As far as positives, it's quiet, leak free, so far, and easy to service.
Would I recommend one? Not the e model, to me the electronic features turned out to be a nuisance. Buy the less expensive non e models if you want a Pro 3. Of course I didn't buy it for the electronics. I bought it because it had the most output of any Eheim I thought I could easily fit in my cabinet. For the most part I'm happy with it. I was able to get a lot of stuff out of the tank and from under my tank.