For all of you sump masters out there...

Why the overflow box? I'm thinking that the water goes into the overflow, then over and into say a 1" pipe. Why not just have the tank water go directly into a 1" pipe that is extended up to near the surface? You could use gray PVC and it wouldn't show too much.

Just guessing, but possible reasons for the overflow box:
1) Less noise, especially if your surface is turbulent
2) Easier maintenance -- you could easily dismantle your drain pipe with an overflow box present. You would need a shut off valve below the tank to do drain pipe maintenance if you did not have an overflow.
3) The overflow box is a good place to bring in the return from the sump and keep everything together.
4) The overflow box is a possible catch basin for any critters that go over the top of it.
5) Aesthetics perhaps...

Just curious...

Ted,

All the reasons you list are very valid.

I have found plenty of fish, shrimp, fry, snails, etc in my boxes. Thank goodness for those tiny nets..............with the plumbing in there, can be hard to catch em!

The big ones you didn't list (IMO) are surface skimming and constant adjustment of the intake. The overflows allows the water to skim off the top OVER A WIDER AREA and without adjustment to the intake. This keeps the surface scum down and facilitates air/water exchange, and looks better

If you just had a pipe stuck straight up, you would have to constantly adjust it or keep the same EXACT water level in the tank at all times. Good luck with that lol

The water collects in the overflows and eventually will be higher than the opening of the intake. The higher this is, the more water in the overflow box and less noise and degassing....

Ideally, (again IMO) the overflow would be thin and run along the ENTIRE back length of the tank. This would be less visible and offer excellent surface skimming if you are into that sort of thing lol


Hope this helps.

Doesn't the overflow box have something to do with restarting siphon in case of a power outage...or something..... been a while since I was looking at plans so I can't really remember how it goes together.

Well the built in boxes do not need the siphon maintained. When the pump is off, the tank drains to below the overflow. The boxes then drain into the sump, which is why you need that extra sump capacity

When the pump is turned back on, the extra water from the sump is pushed back to the tank and then spills over the top of the overflows again and the cycle is restarted.

I had an old siphon type and cannot remember that this was an issue and I am sure I lost power at times, certainly lost the siphon enough at cleaning time.

Thanks, Gerry. It all makes sense ... thanks. I was just trying to avoid putting in an overflow box -- lazy. Running the sump all along the back is an interesting idea. I did find one example on the internet of a sump in the middle of the back. Here is a top view of what I found:



It looks pretty nice. I think it was 6" on the angled lengths and 12" on the long length for a total of 24" of overflow. In this example, the builder always puts 2 drains in his tanks in case one gets clogged. So, there were 2 drains in this overflow.

Ted,

Welcome.

BTW, it is the OVERFLOW that runs along the back of the tank, NOT the sump. You mentioned that twice here............figured it was a ghost in the machine..


The sump should be under the tank or off to the side somewhere............

I have seen the type you mention as well at the LFS. A double drain is also nice.........With 24" of skimming, will do a great job!

Did they have the returns come up through here with the example you saw?


Are you going to DIY? If so, please post steps and pics!
good luck.

Glasscages.com - Overflows

Looking at the section of "freshwater" overflows... What are thoughts on the efficacy and usefulness of the horizontal overflows. They seem somewhat akin to the hang-on-back 3rd party overflows, such as those from CPR.

They seem attractive from the standpoint of them being much less obtrusive, but what would some caveats be, if any, to a built-in overflow like them?



-Jason

That little overflow box looks good, first because it would be easy for one of us to add one to an existing tank, and because it is so unobtrusive. It would also be very easy to keep the inside clean, compared to the full tank height ones. If there is a major disadvantage to it it would be the very small length of the overflow, compared to most of the others. I also liked the little corner one they show, in an acrylic tank, for its unobtrusiveness.

This would be tough to control the degassing of CO2. At least with the internal/corner mount you will have some options (ie, stand pipes)

This will also cast a shadow in the tank due to the distance it protrudes into the tank.

Comparing this to the CPR, the CPR only sticks out 1.5 - 2" into the tank and has a high flow rate(300 gph model CS50, this is their smallest one). Also the flow in opening drop is about 1" and the back box is sealable.

I also like the one that takes up one end of the tank. If using that tank as jutting into a room (so to speak, short end to wall), then that would work well too. Probably kind of like the AquaPod or Solana type "all-in-one" type aquariums...