size of return compartment?

[kismetsh]

First, I have a lot of aquarium experience but have never owned a tank with "plumbing" so I'm a bit lost and hope you guys can help me.

My main DT is a standard 29g. I am planning to connect it to a standard 20L display refugium/macro tank. Drilling is not an option so I will be using a lifereef overflow. I will have about 3.5' of head. I'm probably going to go with a MD5 or MD7 as my return pump. I do not want a normal baffled sump/refuge. My idea is to have a corner acrylic toothed "overflow" to make a compartment for the return pump. The intent is to hide the pump, help keep sand and macro out of the pump, and limit the volume of water on my floor in the case of an overflow failure.

Does anyone see any huge issues with this plan?

Also I need to give the fabricator the dimensions. I don't have the pump yet but the stated dimensions of an MD5 are 5.0" x 3.8" x 4.2" (MD7 states same). What size compartment do I need for the pump to operate correctly?

What about height?

Thanks in advance!

[JonnyD91]

Why would you want to hide the pump in the sump? Do you have a diagram?
I would want at least a 5 gallon area or you are going to be topping off fresh water all the time.

[kismetsh]

Why would you want to hide the pump in the sump? Do you have a diagram?
I would want at least a 5 gallon area or you are going to be topping off fresh water all the time.

It is not a normal baffled sump, it is basically another display (macroalgae/refugium). Hiding the pump is just aesthetics, the other two stated functions (keeping sand/macro out of pump and making sure the amount of water on the floor in case of accident is limited) are more important.

Topping off fresh water daily is a given in a nano. :) In fact now I top off more than once a day so as to keep salinity swings to a minimum. If it became an issue (doubtful) I can set up an ATO.

No diagram (don't have the skills lol) but just picture a standard RR tank with a black overflow in one corner. The pump would sit inside that.

Hope that is helpful! :)

[gbru316]

Just something to think about: To limit the amount of SG change, make the return pump section as small as possible. By doing so, the water level will change more for a given amount of evap vs a larger section. However, ATO redundancy becomes more important as the smaller return section will run dry quicker.

As long as you keep the return section full, you should be ok. If you allow the water level to cascade over the divider between the fuge and pump you might end up with microbubbles.

[kismetsh]

Thanks gbru. Any other input? How much "clearance" is needed around the pump?

[gbru316]

Thanks gbru. Any other input? How much "clearance" is needed around the pump?

Not much, enough that you can remove it for maintenance. There might be 1/2 to 1" of clearance around mine.