Calling All Sump Users

[SkiFletch]

Ok so I've designed my sump thanks to members here, the internet, and just research in general. The sump is easy from a design standpoint if you ask me, but of course difficult to create if you're not experienced in dealing with acryllic.

Regardless, my question to all you sump users is what do you use for overflows? I'm trying to design mine and am a little sketchy on the details of what I should be going for. About the only thing I do know is thatthe overflow creates a siphon directed into the first sump chamber. Also, the overflow should be positioned to break siphon in the event of power loss at a height which the sump's overhead volume can absorb without leaking. Other than that, I'm kind of clueless.

I'm ultimately looking for some kind of hang-on solution as this is not my own personal tank and drilling is out of the question. So should I be going for a u-shaped acryllic box with a tube attached to the other side? Perhaps just a straight up 1" PVC fitting looped up and over the main wall? I was also debating using a nano overhang filter and just drilling out the bottom and mounting a bulkhead fitting there. Whichever method I choose, I'd like to have a minmal impact on the usable space in the tank.

So I guess, what do you guys use for your overflows? What have your years of experience taught you?

 

[superman]

My years of experience has taught me to never trust sipon overflows. They can work great for years, then out of the blue one day it'll fail. I've helped clean up after 4 siphon overflow failures, every person said the same thing "I should never have trusted these &*%*#&@ siphon overflows. In my opinon, Either drill it or get a tank that is already drilled.

 

[crazyelece]

I have both a drilled tank and a siphon overflow tank. Siphons aren't as bad as everyone claims if you plan right. A simple U tube overflow has been the best for me. They require around 600gph flow through them and they will never accumulate enough air bubbles to break siphon.

Here is a link to help you understand how they operate
http/www.csd.net/~cgadd/aqua/overflow.htm

You need to figure out how much water will drain after the power is cut and make sure your sump can hold this. Then set the overflow so that if the siphon does break the display has enough room for the water in the sump (or at least the pump chamber) to be pumped in. If these two conditions have been met and you have 600 gph flow, then you will never have spilt water. The worst that could happen is the return pump could burn up, but you could put a float switch in to turn it off if the water in the sump falls to certain level.

 

[Opcn]

also make sure that your return line cannot backsiphon more water into the sump thanit can hold, because most sumps can't handle the entire system volume and even ifthey can low tide is not generally good for the average reef tank, LPS especally tend to suffer and get ripped off of there skelitons

 

[SkiFletch]

thanks for the input guys, and awesome site there. I've designed the sump so that it has a water volume of nominally 7 gallons when the pump is working. If the pump fails, the sump is large enough to absorb extra water up to 18 gallons total. With the footprint of my tank, that means the sump can take 3.6827 inches of water from the display tank before the sump overflows. Therefore, I plan to design the overflow level AND the return fitting to be more than 2 inches from the surface of the display tank I should be safe from back-siphoning issues. I'm also going to add a 2 gallon topoff tank with a float switch and solenoid valve to auto dose for decreased water level from evaporation and a lower float switch and relay to turn the pump off in the event that the siphon is lost and the pump runs dry.

 

[Aquascaper]

Don't forget to leave the tide zone (the area at the top of the tank that would be left dry if the power went off) clear of corals or anything that could potentailly be lost if allowed to dry out. If you don't you'll only do it once believe me, I did it and killed a £30 Pagoda coral that way

 

[FrankP]

I have an Aqua Medic hang on box which works well so far. It is only 1 cm below the surface of the water so if the pump fails the sump can cope and the amount of water lost is not catastropic.

I have also fittd an overflow switch should the flow from the box slow or get blocked so the pump does just keep pumping into the tank and make it overflow.

HTH

Frank

thanks for the input guys, and awesome site there. I've designed the sump so that it has a water volume of nominally 7 gallons when the pump is working. If the pump fails, the sump is large enough to absorb extra water up to 18 gallons total. With the footprint of my tank, that means the sump can take 3.6827 inches of water from the display tank before the sump overflows. Therefore, I plan to design the overflow level AND the return fitting to be more than 2 inches from the surface of the display tank I should be safe from back-siphoning issues. I'm also going to add a 2 gallon topoff tank with a float switch and solenoid valve to auto dose for decreased water level from evaporation and a lower float switch and relay to turn the pump off in the event that the siphon is lost and the pump runs dry.

 

[crazyelece]

An easy way to fix the return back siphon is to drill a hole in the return line just under the water surface. When it siphons below the hole air enters and breaks that siphon. This way you can output the return at any level you wish and not have a problem with water going back when power is turned off.

 

[Aquascaper]

An easy way to fix the return back siphon is to drill a hole in the return line just under the water surface. When it siphons below the hole air enters and breaks that siphon. This way you can output the return at any level you wish and not have a problem with water going back when power is turned off.

Do two holes to be safe, one may get blocked

And include in your daily checks to make sure they're clear of any debris.

 

[SkiFletch]

Great idea, thanks guys