Hmm. Struggling with pump selection.

I'm leaning towards the Mag-Drive 950, as I don't think the Mag-Drive 700 will have quite enough oomph. Nothing that I've tried in the link provided by Greg seems to be anywhere near the right flow for my liking. The 700 will wind up under 400gph, and the 950 will wind up closer to 600gph.

Now, I can use the ball valves on the return system (there will be three of them) to decrease the flow into the tank . . . right? Can this harm the pump?

As for valving;
If you're talking about restricting the drain pipes with valves, ya there's no harm. This is how you balance your overflow.
If you mean restricting the return side of the pump, some pumps won't last as long with restricted back-pressure.
My overflow can't quite handle my return pump ( drain design issues ), so my main drain gate valve was a waste of money :rolleyes:
I installed a Tee with a ball valve to regulate my return flow. The Tee is after the pump, so there is no restriction at all
This is what mine looks like ( on the right )

http://i749.photobucket.com/albums/x...uild/Pumps.jpg

For pumps;
Mag drives are somewhat noisy and create heat
Eheim pumps are great and you could probably get away with a 1250, but don't go buying one yet. It's listed in the Head Loss calculator, but ...
Post your estimated plumbing info and hopefully someone with a similar experience will help steer you in the right direction. I don't want to be the only one recommending it :smile:
For a 40g breeder, IMO, 400g/hr is lots
Others may say different, but I'm targeting just over 600g/hr for my 75g

The total flow requirement for you tank is a combination of internal flow and return flow.
The return flow needs to be low enough that your skimmer can do it's job.

Hopefully others will chime in with exact #s for you

OK, I'll start the #s input ...
If I remember wrong, someone should correct me :wink:

Basically, the amount of total flow needed for a FOWLR or lightly loaded LPS tank is around 10-15 times turnover/hr

An SPS tank needs 15-20 times turnover/hr or more

So, if your return pump is giving you 400g/hr in your 40g, you then need another 200g/hr with powerheads

Now ....

Where are all the answers needed here for the correct return pump flow in this 40g tank ?? :razz:

The skimmer is an SWC 120 cone (I don't have it yet, it is my Mother's Day gift).

It has an Atman 1100 pump. I'm having a hard time finding numbers for that, but I've only had a cursory search.

Based on the SWC website, the skimmer is good for 55 gallons with a heavy bio load. This system will be around 55 including the sump.

I have an Eheim Compact 2000 as my return pump right now, and I really like it. It is very quiet. I would prefer to use an Eheim in this system.

When hubby and I have all of the plumbing done I'll post the exact set up. I'm guessing when I use the calculator right now, but I should be close. I think the Eheim 1250 came out around 300gph (if I remember correctly).

I have one little 425 gph powerhead that will go in this tank for now I'll be adding a second cheap (larger) one. (Maybe I'll get my twin mp10s as a gift from hubby . . . If I behave ;))