Construction of New Refugium ??

I have a 20L AGA tank I am going to use as a sump/refug. I will have a skimmer section, a refug section and a return sump. My question is how tall or low do I need to make the dividers in order to compensate for water going back down into the sump/refug when the power goes out?? The tank is 30"x12"x12", I am planning on making the refug area at least 9 gals which is 10% of the 90 gal main tank. The main tank is drilled and has the AGA overflow system. This is my first sump/refug and I am about to install the dividers so I thought I would ask for some pro advise. The design I like is http://www.3reef.com/forums/attachm...2221-my-29g-sump-refugium-plans-29_g_sump.gif I know it is a 29g but I would like to use this design but to my 20L, Thanks for the expert advise in advance.

 

My dividers are fairly close to the top of the tank, but how you place them is really determined by how much water will flow back into your sump after the pump is turned off.
For example, on my supply line to the tank, I only have one line and it goes from pvc pipe to a flexible black return spout. This line is partially out of the water so if the power does go out, the siphon is broken rather quickly so only about a gallon goes back into the sump.
If your return is well below the water line then you can drill a small hole in the supply line over the top of the tank so that the siphon is broken.
you will have to do a test to see how muck flows back into the sump before the siphon breaks. Understand?? There are some other posts with good illustrations that probably explain it better than I have Let me see if I can find them.

Jim


Melevsreef.com - What is a Sump?

Look at this picture and see if you get the idea. notice where the circle is located (drilled hole) on the return line a little below the water line.

 

Would one really need to divide their refugium to make part of the tank a sump? Why can't the tank be used as a refuguim and contain the skimmer? Is there any harm, and the mud can not be drain up into the pump of the skimmer.

 

Usually the refugium has many good things that you dont want the skimmer to take out such as copepods and other good organisms.