return pump ??

[Elite Twit]

OK, posted on rc, but i guess no one out of the however million members don't know...:| uh what? Anyway after my filter crapped out I am redoing the entire system, here is my post from rc, hope someone can help me out....

 

My friend had the tank, and I have some free time so I wanted to see how this worked out. Let me know what everyone thinks.

 

I am going to add a fuge to my 7g nano and 3g seahorse tank. I am planning to connect them all in one and was going to try and use on eheim hobby pump. I am looking to get about 30gph for teh 3 and around 170 for teh reef. Am I correct in assuming if I use one pump to branch off into two returns via tee connection I will halve the gph from teh pump? If not how exactly is this calculated? I am going to put in ball valves to restrict flow, but I am not sure of what happens when I split the flow to two different places. Any help would be greatly appreciated.

Thanks,

Jay

Ps I was planning on using the 1250, which has 320 gph. The 3 will be approx 4 feet from pump, and teh 7 will be 3 1/2. This pump has max head of 6.5ft. They both will have 3 elbows, tee included. 1/2 inch PVC. all teh way up. Is this pump too powerful? should I go with the 1048 which has 160 gph with max head of 5ft? Thanks again

[MKramer]

Because the length of hose is different from the tee to the two tanks, the dynamic head on each side of the tee will be different, and therefor the flow will not be 50/50. But it should be fairly close, as long as both sides contain the same number of fittings (elbows, unions, valves, etc). I'd definitely go with a ball valve on each side of the tee to manage the flow.

 

As for the pump size... By my rough calculations, your total dynamic head is about 5ft. That's the statif head (max vertical head) plus head loss do to friction and fittings.

 

The flow rate of the Eheim 1250 at that head is about 150gph, which using the ball valves, you can pretty much divide amongst the two tanks however you want. But that definitely falls short of your goal.

 

The next Eheim up, the 1260, will give you about 270gph at the head. More than you want, but you can reduce it down using the ball valves.

 

Re-reading your post, I wonder if you meant that you wanted 70gph, not 170gph, for your 7g, in which case the 1250 would be your ebst bet. The 1048 would probably produce a trickle, or just plain fail, in this setup. If you want to save some money, I'd also recommend the Mag3. It should be submerged, though.

[Elite Twit]

Thanks. Tha'ts exactly what I needed. I was hoping for 150 for the reef, 170 was a higher estimate to cushion myself, but 150 was my actual goal. As for teh seahorse tank, a trickle is pretty much the idea. How exactly do you figure out these numbers?

Thanks again.

Jay