Convert Internal Overflow to Closed Loop

[MaddyP]

So, I purchased a tank recently with a internal overflow. I have a Synergy overflow on my other reef I plan to install on the new reef. As I was contemplating how to plug up the holes in the bottom after removing the internal overflow, an idea came to me. Why not turn the existing holes into a closed loop? I could use the 1.5" as intake and the two 3/4" holes as returns. Maybe a Varios-4 would be a good fit...

Thoughts?

 

[Greybeard]

There's no reason why not... Closed loop systems aren't as popular as they once were, since internal wavemakers have improved dramatically. There are still folks around who like them, a way to provide a great deal of water movement with no in-tank equipment.

 

[MaddyP]

There's no reason why not... Closed loop systems aren't as popular as they once were, since internal wavemakers have improved dramatically. There are still folks around who like them, a way to provide a great deal of water movement with no in-tank equipment.

The increased water movement with no visible equipment was the idea. It wouldn't need to be a large pump as it's only 75 gallons, but it would allow a bit of flow behind the rocks.

 

[Dave1045]

Im current thinking about doing the same thing on my new 180 build. What did you end up deciding on yours?

 

[MaddyP]

Im current thinking about doing the same thing on my new 180 build. What did you end up deciding on yours?

I'm still on the fence. I don't know if a closed loop in a small tank like mine would benefit the tank greatly. I think if I wanted to go all closed loop and Drill a few more holes it would be worth it...

 

[Grey Guy]

With a closed loop, will you run without a sump? How will you filter your water? I like the simplicity of it. I'm not real ambitious about what I want to do. Just seems crazy expensive to go all out SPS.

 

[Grey Guy]

Any water tight reactor (such as cheato) could be run in a closed loop couldn't' it? I just don't see running a good size skimmer without some kind of a sump.

 

[Greybeard]

Any water tight reactor (such as cheato) could be run in a closed loop couldn't' it? I just don't see running a good size skimmer without some kind of a sump.

SEALED... yeah, you could run a sealed reactor. The reason for a closed loop is usually circulation, so they're generally fairly high flow, most reactors won't want that much flow.

As to Skimmers, _not_ a sealed device, but there are external skimmers that don't need to be in a sump. You could pump from the tank, through an external skimmer, and drain back to the tank. I'll admit to never seeing such a setup, but I see external skimmers sitting outside of a sump regularly. Used to run an old Precision Marine Bullet2 that way. Worked great, sounded like a jet engine

 

[Grey Guy]

SEALED... yeah, you could run a sealed reactor. The reason for a closed loop is usually circulation, so they're generally fairly high flow, most reactors won't want that much flow.

As to Skimmers, _not_ a sealed device, but there are external skimmers that don't need to be in a sump. You could pump from the tank, through an external skimmer, and drain back to the tank. I'll admit to never seeing such a setup, but I see external skimmers sitting outside of a sump regularly. Used to run an old Precision Marine Bullet2 that way. Worked great, sounded like a jet engine

My Aqua C can be placed above the tank and work as you say. I'm just entertaining different ideas in my head. Other than the space it uses, a sump just seems so easy.

 

[Greybeard]

My Aqua C can be placed above the tank and work as you say. I'm just entertaining different ideas in my head. Other than the space it uses, a sump just seems so easy.

I really can't imagine keeping a marine, much less reef, aquarium without having a sump. I set up my first sump in about 1988, haven't even tried to set up a tank without one since. Increases your options dramatically.

 

[MaddyP]

I went ahead a sealed the holes. A closed loop was only on my mind to improve flow, but it didn't seem worth the trouble.

 

[cracker]

A buddy of mine has got one not setup exactly like yours but works just fine.

 

[Grey Guy]

I have started running a closed loop. I like it so far. Getting lots of tiny bubbles though, even with the skimmer off. Not sure why. The overflow box is filled to the top. I love all the room in the cabinet to move stuff around and put whatever I want. Right now I have a tank for salt mix and a smaller tank for makeup water. Both have float valves and are fed by the RO/DI unit, and of course, the main circulation pump, with an access valve on the suction side for adding salt or fresh water.

 

[Grey Guy]

I have started running a closed loop. I like it so far. Getting lots of tiny bubbles though, even with the skimmer off. Not sure why. The overflow box is filled to the top. I love all the room in the cabinet to move stuff around and put whatever I want. Right now I have a tank for salt mix and a smaller tank for makeup water. Both have float valves and are fed by the RO/DI unit, and of course, the main circulation pump, with an access valve on the suction side for adding salt or fresh water.

Update: I drilled a large hole in the side of my internal overflow with a glass cutting hole saw and installed my circulation pump near the top. The water goes into the overflow, feeds the pump which has 3 main discharge ports into the display. It’s been working now for about 6 months. I still like it. I have no refugium and hardly ever have to dive into the cabinet below. I found that DC pumps have a lot of flow, but not much head pressure, so that the less the water has to rise to return to the tank, the more flow. This setup really boosted the flow compared to having it under the tank.

 

[ca1ore]

I don't personally like to run anything that uses bulkheads that are 'open' to the full volume of the tank. What happens if one starts to drip, as bulkheads can do? Answer is that you have to completely drain down the tank. I like and do use a closed loop, but both the suction and returns are along the top of the back of the tank.

 

[Grey Guy]

The water is overflowing into the overflow to the suction side of the pump. So it doesn’t matter if the bulkhead leaks or not. I need to send a photo.

 

[Grey Guy]

The water is overflowing into the overflow to the suction side of the pump. So it doesn’t matter if the bulkhead leaks or not. I need to send a photo.

Here is an old photo that shows the pump pulling from the overflow. The bottom of the overflow has bulkheads in it, so that does provide the possibility of leaks. But then I would only have to drain the overflow and not the whole tank.

 

[Grey Guy]

I really can't imagine keeping a marine, much less reef, aquarium without having a sump. I set up my first sump in about 1988, haven't even tried to set up a tank without one since. Increases your options dramatically.

An external sump, I would totally agree. But I just hate getting up and down to work under the tank.

 

[Greybeard]

An external sump, I would totally agree. But I just hate getting up and down to work under the tank.

My sump is in a closet behind the tank, about waist high. I'm old and fat... no working on my knees for me, thanks.

 

[Grey Guy]

My sump is in a closet behind the tank, about waist high. I'm old and fat... no working on my knees for me, thanks.

That’s the way to go. It’s all about having enough room.