flow in a 180 aga mega flow

[tsdid]

Im hoping someone can help me. I have plumbed up my aquarium planning on using a pump I recieved with this used system. It is a large RK2 pump that is speced at 3500gph. I am plumbing the return via 1inch then it tees off to 2 1inch then tapers down to .75 for the return. I had it fill up a bucket and I calculated that 1600gph was going through the return. When I test ran the system this worked great. My problem is the pump is leaking, I tried replacing the seal but it still leaks so I need a new Pump. Does anyone have any suggestions? I would like as much flow as I can get, however I know the overflows can only handle 600gph each. Not sure why all the flow that was going through my system worked, any thoughts suggestions.

 

[gregzbobo]

I've been out of it for a while on non-nano equipment, but the Iwaki japanese made pumps used to be VERY good and likely still are. I have a Little Giant 3MDQX-SC for the return on my 65, and its been running since 2002, got it direct from the factory (factory is a few miles from my apartment) as a refurb for 90 bucks. It runs pretty warm, and its on a THICK piece of foam to cut noise, but I oil it every few months and it runs like a charm.
Why is your return line 2 different sizes, is that an attempt to cut flow? If so, it'd be easier not mention neater to make it all one size and put a shutoff valve in there between the pump outlet and the tank, and just dial the valve down to the flow you want.
I have an older AGA 65 with the built-in overflow in one corner, I made the spacing on the "teeth" of it bigger to handle more flow, theres a mod you can do with some gutter grating that would increase drain-flow tremendously. Search durso standpipes, click the first link in the google search and then find popular modifications. If no luck with that search, PM me for a direct link.

 

[tsdid]

Im not really looking to modify the tank at all. The thing is the tank was getting some nice flow with this pump. when I mentioned the 1600gph previously that was probably a bit high, when I was testing it the height was only about 3 feet off the ground. I dont really have two differant sizes going from my return, the pump has a 1.5 inch out and I had that taper down to 1, from there it when up and teed off with a 1inch tee, after the tee I have it taper down to .75. I did this so that I woulnt get allot of back preasure on the pump. I guess Im just looking for a good pump that will supply more than sufficiant flow after all the head loss and loss from tees etc.