Maintaining water level in the sump

I wasn't sure where to put this thread exactly so this seemed like the most logically place. I just set up a 125g reef tank with a sump and this is my first attempt at setting up a sump. I have always used canister filters and HOB skimmers and had great luck but wanted to minimize the amount of equipment out in the open for a cleaner look. My main issue that I am having is that my sump water level won't stay consistent. No matter what I do it either is going down or going up. I understand that the water level within the tank should stay the same and the water level within the sump will fluctuate some but it should also stay the same level minus evaporation amount shouldn't it? I am running a retun pump that is rated for just under 1600gph and its hooked to a 3/4in return line that has a Tee to the two retuns in the tank wall. The appox distance from the pump to the returns is about 4-4 1/2 feet. My LFS and some others that I have talked to and the research I have done said that this should be about right for the power of the pump. Is this pump too strong? Thanks for any help on this guys, I'm a sump newbie haha.

 

I'm pretty much a sump newbie as well. I'll let the expert plumbing/sump people respond on specifics but in answer to your question, the sump level should stay relatively stable with evaporation happening in your return section. Evaporation should be slow in general.

 

What type of drain did you install? If you just ran pipe without an air vent, it could be getting air-locked (still drains, but in surges). Don't know if reducing flow would help alleviate that to any degree, but 1600gph for a 125g tank is a bit too much; for optimum efficiency from your sump, your flow should be around 625 - 750gph.

 

It has two one inch drains that have two ball valves on them, I've played with them a little but I have had more luck with have them almost wide open and then playing with the ball valve on the return. There are no air vents or check valves but I do plan on installing them in the near future. With the flow though, it would be returning about 650-750 gph in each of the returns since there are two, idk if that affects it or not. Its all soft hose drains adn returns right now. I plan on hard piping it with either PVC or Pex when my brother-in-law is free since hes a plumber haha but until then I'll have to use what came with it.

 

You never want to restrict the drain.Also check valves can/will fail so using them is not recommended.It is better to adjust the overflow so that a power failure will cause the return to become exposed to air thus breaking the siphon and stopping any possible sump overflows.

 

+1 on never restricting the drain. make a durso type overflow that will help vent the line and get air into it so it doesn't surge. http://www.dursostandpipes.com/make-your-own-durso-standpipe

 

^^yes to the Durso.. a quick and simple build.

 

As already mentioned, never restrict the overflow. Install a ball valve on the discharge side of your pump to control your flow there and the overflows will match that flow perfectly by gravity alone.

I also say no check valves, they are a false sense of security and can and will fail. It does not have to be a catastropic failure, even a trickle will cause a flood in time.

Here is the best article on sumps on the web:
Melevsreef.com | Acrylic Sumps & Refugiums

My only reservation is Marc's recommendation on installing a tee in the return line and bleeding water back to the sump. This is old school and uses much more power since the pump is working harder and also is louder and creates more heat. It is much better to restrict the flow with an inline valve which adds additional head and believe it or not makes the pump work less so consume less power and create less heat.

I also agree on the simple standpipe design but rather than the Durso I prefer the simpler and cleaner Stockman design also found on Richards site.

 

Yeah, without an emergency drain you're going to get a flood.
Do you have pictures?

 

Ok this is probably a dumb question but how do you install an over flow on a sump with bulk heads? All of the overflows I've seen are HOB overflows.