Overflow Box Significance.

[Bedroomgangsta]

I recently added a 29 gal sump to my 55 reef DT. I custom made the sump with only 4 panels which consists of two 16" panels, one on each end from top to bottom(about two inches from bottom of tank) and two 10" panels in the middle of the tank to host my in sump protein skimmer. I just built it on my own, didnt feel the need for a bubble trap or anything extravagant. For my overflow I used simple 3/4" pvc pipe and 3/4" vinyl tubing for my drain and my return. I have a ball valve midway through my return line and a mag 7 return pump. I have trouble getting it to return at an exact rate of flow as the drain. Ive got it tuned in now but sitting by the base of my tank for an hour is kind of a pain and Ive been told that a simple over the top U-tube such as my current setup is far too hard to maintain and a disaster waiting to happen. I have an Eshopps 300gph overflow box on the way because of it. My curiousity has been getting to me in the "significance" of the box rather then an over the top U-Tube. Is it so hard to maintain an exact Drain/Return ratio because of the water volume in the DT is constantly changing due to evap and disturbances from my Koralia powerheads? Is an overflow box designed to keep the water volume/pressure consistant so that your drain/return ratio is dead on? I wanted to minimize the eye-sores in my tank so I thought the u-tube would work just fine....but IME its not working that well. I really hope someone can answer my questions and give me some insight on how to fix this issue and also how to make it failsafe. My overflow box has a 1" bulkhead and my current return is only 3/4" but my ball valve is pretty sticky so i thought perhaps maybe I should replace it but before hand Id like to know if I need to replace the 3/4" tubing with 1" to match the drain, or possibly even larger if needed. I would greatly appreciate any information! Please Help.

[wbdevers]

I'll see if I can answer some for you.

have trouble getting it to return at an exact rate of flow as the drain

Open the ball valve on your drain all of the way and then control flow with your return ball valve (hope you have one).

I have an Eshopps 300gph overflow box on the way because of it. My curiosity has been getting to me in the "significance" of the box rather then an over the top U-Tube

The overflow box acts just like the U-Tube set up--in fact some OB's use the tubes. Even though you will be evaporating from the entire system, you will see it in the sump. Do you have or will you soon have an ATO system? If you set one up and have the float switches in the return section it will maintain your water level for you (as well as SG). Your power heads and such won't affect the water level.

My OB sat very low in my tank and caused a couple of problems--loud drain sounds and it caused the water level in the tank to drop to a level I didn't like. I raised it up on the back of my tank and presto--no noise, tank level is where I want it and it skims the surface better.

I wanted to minimize the eye-sores in my tank

I've only had mine running since the first of the year and it already has a ton of coralline on it--eyesore will be minimized IMO.

My overflow box has a 1" bulkhead and my current return is only 3/4" but my ball valve is pretty sticky so i thought perhaps maybe I should replace it but before hand Id like to know if I need to replace the 3/4" tubing with 1" to match the drain

There is no need to match the two sizes. I've got the same--1" down, 3/4" up. Ball valves (esp PVC) are sticky for a while. Especially the bigger sizes, but with use they will loosen up some. I've got one on the drain and return. the 3/4" is much easier to turn than the 1".

Hope this helps.

[Bedroomgangsta]

thanks a lot wes I appreciate it. I thing is I dont have a valve on my drain, just on my return. I figured you wouldnt need one on the drain because it seems kind of useless. I like the idea of just the pvc in the tank but hopefully the box will do a better job in keeping things steady. I appreciate all the input I needed it, for my first time sump build and all...so thank you.

[wbdevers]

It wouldn't be a bad idea to have one, because that way you can isolate the tank from the sump in case you need to work on the sump etc. Also, did you by chance put unions in line? Another good idea, because it lets you disconect any hard plumbing.

One other thing, make sure you have a siphon break on your return in the tank--will greatly help reduce any floods.

No problem. I built my sump from scratch with acrylic--not pretty but it works very well--I'm actually quite proud of it. I had similar questions so I know how it is.

If I can help some more please feel free to ask.

[seapug]

You always want your drains to be larger than your return lines. Wide, free flowing drains are the key to silent, worry free operation.

I'm not sure if I completely understand the DIY drain you made, but it sounds like you simply have a 3/4" piece of PVC as your drain/overflow. If so, the problem you are having is probably related to the relatively small drain being "overwhelmed" by the surge of water from the powerheads in the display. What an overflow box does is provide a larger surface area drain to accommodate the surges that come from currents within the tank.

As for the HOB u-tubeoverflow box, most fears about them are exaggerated. Many people (including me) have used them for years without issue. I would just recommend using one that does not require any additional pumps to maintain the siphon. They are a little intimidating to start (you usually end of with a mouthful of saltwater), but once you get them started they are very reliable. Afterall, there's no such thing as a gravity outage. I typically pull the tube and clean it a couple times/year to keep it free of buildup that could slow the flow.

Do not rely on a siphon break to prevent the sump from overflowing in a power outage. They are destined to fail in a marine tank with invertebrate life. The only way to guarantee you won't have a flood when the return pump shuts off is to keep the water level in the sump low enough to accomodate the back-siphon from the return.

[Bedroomgangsta]

thanks a lot again guys I appreciate it. I should be adding the overflow box probably tomorrow or friday and well see how it pans out. I have a 1" bulkhead on the overflow box and Im curious what pvc/hoses/tubing I need to hook it up properly? will pvc just hook right up to it depending on the thread pattern? and then must I use pvc for the entire drain because currently I just have vinyl tubing to provide the leng of drain pipe needed, as well as the return.

[wbdevers]

I'm not saying to rely solely on the siphon break but it is not destined to fail if you keep it clean just like everything else. I clean mine a couple of times a week with a toothbrush and I test it a couple of times as well--part of my maintenance routine. Yes, of course make sure your sump can hold any back flow.

Yes it should fit right on as long as the threads are the same. Generally it is a socket fitting but yours could be different. Also, yes you can use the vinyl that you have--you will just have to go from PVC to hose which is a barb fitting.