Help with sump/refugium

I have been looking into building a sump/refugium for my 40 gallon reef tank and just have a few questions on the mechanics behind them.
I have gathered that they operate on a siphon feeding out of the tank/into sump, and a return pump back into the tank. How exactly is this accomplished? Are the pumps adjustable to match the siphon flow, or does the pump basically create its own siphon through the system?
And what size do you feel would be best for a 40 gallon tank? I have this 10 gallon sitting around that I was going to use, or should I go bigger?
Thanks for any info!

 

1.) if you get an overflow... you just make sure the pump is not rated higher than the overflow... ie 400 gph pump and 600 gph overflow = ok... 600 gph pump and 400 gph overlow = disaster

2.) wouldn't need a very big one for a 40 gal... my guess would be go with whatever sized overflow you want (at least 500gph) and throw a 400gph pump on the return
personally... after I've seen one... I'd just build it. you can bend acrylic with a $25 heat gun... make an external box making sure to build 2 sections into it(one for u-tube, one for outflow)... put a 1" hole in outflow side... toss in some 1" pvc in outflow side... buy an overflow u-tube for 7.99... make an internal box... voilla... of course you can buy one for $40 on ebay.... maybe just go with that!
3) important thing is that return line doesn't go very deep into display tank... cause it will siphon back till it finds air...
4) another important thing is that the siphon 'restarts' whenever power goes out... for this reason you will find most people recommend the u-tube type and not the cpr guys... u-tubes hold their siphon much better.

good luck!!!!

 

i agree, but if it is possible drill you tank and make and overflow you will like the result if that is possible drilling would probaly be a cheaper option i did that to an old 55 i got the glass hole saw from glass-holes.com for a couple of bucks its up to you i would say go as big as you can for your sump more water volume more stability in your parms

 

Glass is tempered all the way around. Drilling is not an option
I think I will probably just buy an overflow box. It seems easier than molding acrylic and that way I will know exactly what the flow rate is.
Would the flow rate need to be increased with a larger sump/fuge, or is that more dependent on the size of my actual display tank?

 

you want to try to get the highest turn over rate you can most try to shoot for 4 to 6 times an hour but a well stocked reef 7 to 10 times an hour

 

OK.
I'm still a little confused about the overflow/pump ratings. How would a 600pgh overflow with a 400gph return pump even work? Wouldnt the sump be taking in more water than its returning?

 

As long as your return pump is equal to or less to the OFB, your fine. Luna

 

The water draining from your main tank to your sump/fuge will only drain as much water as your return pump can pump back to the display.

I would also recommend buying a switch that turns off the return pump just in case your overflow fails for some reason. I use one that is maid by blue line that works on pressure that has been reliable so far. If the water level goes too low in the fuge/sump it turns off the return pump, then turns the pump back on when the water level goes back up. This way you don't accidentally overflow your main tank if the siphon fails on your overflow. It also stops your pump from running dry if your siphon fails.