final assembly/design sump qusetion

[gravismaximus]

trying to know what to expect will happen. this is my first sump and thou ive done some research it cant hurt to ask for opinion on the design and a couple of questions. so here goes, my overflow will flow quicker then my return pump will pump. so how do i keep return pump under water? if my return section fills up untill the skimmer box (theeth) is even with the DT water level it would force it to always be filled up above the pump. due to the pump puting the water needed into DT to flow into the skimmer box to go back into the intake of sump, right? and if i do that then wont the water level be at the point that even if i lost power or pump went bad that no more water could get into sump anyway. this is a win win isnt it. or will the shiphon brake if the water level gets to that point. skimmer box has theeth so tube is lower then the theeth right?
if it would loose siphon then the problum would be when pump came back on it would empty return section into DT, and possibly over the brim.
i will have a siphon brake on both the intake and return tubes, above the water level in sump for the intake and above water level in DT for return line.
the return section of corse is so big because thats the only section thats not already full of water, and is the overflow portion of the sump. am i making this section way to big? if the water level is already at the bottom of the teeth then how much could get siphoned out? just whats in the lines right?
the holes in the intake section will be down towards the bottom to help prevent bubbles from skimmer from getting through. the holes going to the refuge section will be up high so the sand bottom dont get sucked through the holes due to the water movment. thanks for the ideas and help not flooding my house.

 

[acrylic51]

If your overflow pumps faster than your return pump you'll have issues keeping a siphon in the overflow period. The way around this would be to match the over flow and return pump as close as possible. If the return is to strong or fast it will suck the return section of the sump dry causing the tank level to rise and possible over flow the tank. You would assume by adding water to the sump/return area would solve this; this would/could lead to a flood possibly in the event of a power outage. You have to properly set the water level in the sump.