<a href=showthread.php?s=&postid=9714210#post9714210 target=_blank>Originally posted</a> by nebraskareef
Drill your venturi straight through and enlarge it just a little. Thats what I did on my recirc and it started without blowing into the hole.
Trust me, it works.
Did you drill through the hose barb or just take out the 90 degree bend in the grey piece? The Octopus mod thread is too big to sort through.
<a href=showthread.php?s=&postid=9714459#post9714459 target=_blank>Originally posted</a> by hahnmeister
Thats a sign that whatever you have done to the impeller is causing it to drag too much for the startup torque of the pump to start the pump. By adding air, you are decreasing the fluid resistance in the pump so it can start. The impeller may be too heavy, or, just too large in volume (diameter or thickness) for the pump's magnet. I would trim the diameter, as I believe that these pumps have much wider impellers than what is needed. Either that, or remove some of the mesh/thin it out.
Otherwise, that pump is a 600gph pump otherwise, right? Well, an eheim 1260/1262 would be expensive, but you could mod it easily to destroy the output of any of the above pumps... maybe the eheim 1250 needlewheel would be a good match actually. The only other pump I would look at is the Oceanrunner... as pointed out... its a direct replacement. As for Gen-X and Sedra... dont bother. The sedras arent worth it, and the Gen-X at this level is a 2400... a crappy pump that doesnt perform as well as its larger cousins (4100 and 6000s are beasts, but too large for this skimmer).
Well, I just so happen to have an OR 2500 and an extra needle wheel because I broke the ceramic rod on the original. I might play with it this weekend. Just been frustrated lately. I might try to find some gutter guard and see how that works. I would like to think that the original needle wheels are too much (large) for the pump. Thanks for the suggestions!