DIY HOB overflow

[joshuacohenjc]

i am setting up my first sump (for my 75 gallon mixed reef)
it will be located in the room directly behind the wall.
i am planning on building a diy overflow but i have a couple of questions

what if the return pump isn't strong enough and doesn't send the water back as quick as it receives it
what if the return pump is too strong and send the water back too fast and empties the sump

I've seen people drill a hole in a HOB filter (aqua clear 30) and have the water pumped into the filter though the built in pump, and then go down into the sump instead of back into the tank, and since i have an extra one i thought i might try it but how do i make it that the water comes in at the same rate as the return pump sending it back

 

[Ulta]

Drill the tank if you can!
This site has great DIY Overflow kits for drilling your tank:
Glass-Holes.com dope aquarium stuff

 

[joshuacohenjc]

i can't drill, tapered glass :(
and the tank is set up already

 

[joshuacohenjc]

*tampered

 

[Tim]

All you really need to do is put a ball valve in the line from the overflow to the sump, that way you can regulate the amount of flow going into the sump to match what the return pump puts out.

 

[Bifferwine]

You shouldn't restrict the flow going down into the sump. The overflow works as the water level rises. So it can only move as much water to the sump as the return pump is sending back. The overflow will never send water to the sump faster than the return pump can move it back unless it is positioned too low in your tank.

As for the second part, it's very possible for the return pump to be too strong and return too much water to the display tank. This is why you need a ball valve AFTER the return pump to dial it down if need be. To avoid putting back pressure on the pump, I prefer to make a tee in the lines, so that one part of the tee goes to the display tank (with a ball valve) and the second part of the tee goes right back into the sump (with a ball valve). This way, if your return pump is too strong, you simply redirect some of that water back into the sump.

 

[joshuacohenjc]

one more question, i never really thought about this my dad suggest it
the overflow brings the water into the sump, the skimmer (coralife supper skimmer 125) is in the sump, the the filter (fluval 405) will take it from the sump and bring it to the tank.
so basically using the built-in pump in the filter as the return pump

so my question is, will the carbon in the filter stop everything that should be passing through from the refugium, in other words, will the filter kill off all the good stuff that the refugium is bringing in

if i don't do this, how strong should the return pump be (gph)
i have a marineland maxi-jet 1200, which in powerhead mode is 295gph
is that strong enough

 

[Ulta]

Your gonna want a pretty powerful pump because your going to have quite a bit of head-loss.

Head-Loss Calculator:
http://www.reefcentral.com/calc/hlc2.php