Flow Rate help: first tank

[gridley]

My wife and I are setting up our first tank. We have finished the plumbing and are ready to do a test fill with fresh water to check for leaks and to determine the appropriate water level. It has been suggested that I may not have enough water flow . . . so, in the desire to do this right, please advise . . .

My tank is 90G, and the sump, if compleltly full would hold 32G - a more realistic working volume would be closer to 23G (I think). My main drain is 1 1/2, I have a 1" emergancy drain, the return line is 3/4". My pump is a Laguna Max-Flow 600 (600gph). I realize that this is not a standard aquarium pump, but it is what came with the used system. Based on a recommendation I ran the following numbers through the Head Loss Calculator on Reef Central. The laguna pump is not listed on the Head Loss Calculator so I substatuted it with the Eheim 1060 which has a very similar gph rating. http://reefcentral.com/index.php/head-loss-calculator The vertical lenght is 4.25 feet; horizontal length is 1 foot; the pipe diameter is 3/4"; there are 4 90 degree elbows. This works out to 333 gph flow. It was suggested that I replumb the return line to 1". In that case the flow rate increases to 381 gph. However . . . The plumbing at the exit is a 3/4" fitting for the Lok-Line.

In addition I have two Hydor Koralia 2 powerheads at 600 gph and one Hydor Koralia 3 powerhead at 850 gph.

1. Do I have enough flow through the sump with the 3/4 line? (approx 33 gph)

2. Is there enough benefit to replumb and go with the 1" retrun line and gain approx 50gph of flow through the sump.

3. With the restriction to a 3/4" fitting for the Lok-Line, does that in effect create a 3/4" return line?

4. With the Hydor Powerheads (2050gph plus the retrun pump) do I have enough total water flow in the tank?

Thanks for the help.