Returm pump query

[davemercier]

Hi again, yeah, yet another question! I currently have a CPR 100 overflow box, yup, i rushed into a deal on a non reef ready tank! Anyway, i'm using an aqueon 3500 return pump that's rated at 750 gph with it, and i assume that rating is with no head pressure factored in so i'm guessing my actual flow into the tank over the rim at 4 1/2 feet is around 500 gph? It seems to be running fine, quiet, no up and down flow surges like i had with another overflow box that went into the dumpster, but as always, i really love getting opinions from those who know more than i do. I understand about the maintenance requirements of bot the box and the pump that keeps the syphon clear of air. Thanks for any sage advice here!

[Reefmedic79]

Don't know if there is an actual question, but I can't seem to find any info on the flow rate of the Aqueon 3500 with 4.5 ft of head pressure. The total head pressure on a pump will not only be determined by the height of the pipe, but also by the linear length, the number of turns and or number of fittings that are used.

[davemercier]

Hi again Reefmedic79, the aqueon 3500 is rated at 750 gph. I'm asking if that's a good sized pump for the cpr100 overflow box. I have a 4 1/2 foot rise with the 3/4" I.D. hose running at about a 45 degree angle upward, and ending with the over the tank rim style fitting with 3-90 degree elbows. I did the calculator on this site and it suggests 545 gph for me.

[Reefmedic79]

CPR cs100 Overflow is rated for 800gph so it can probably handle a larger pump if you wanted, but what you have would be fine.

Is this on your 72Bow?

[Mr Cob]

I think that pump is fine.

[davemercier]

Yes Medic, it's on the 72 bow. I wonder if one should try and match a pump with the overflow box so that it provides enough actual output after factoring in the head pressure etc, to exactly match the flow rating of the overflow box, as in getting it to as close to the cpr100's 800 gph rating as possible? Maybe to get the most flow in the tank that one can? I've heard though, that the stronger the pump, the more noisy it can be as in gurgling in the drain pipe. Thanks everyone for your input!