Sump system/ overflow/ drilled tank questions

[Ian14]

I'm trying to find a large tank of craigslist and I came across one that the seller said was 86 x 27 x 31. The tank is pre drilled but there doesn't seem to be any over flows in the pictures. Does a tank need overflows to have a sump system in a drilled tank? I'm still not totally clear how that all works I'm still trying to understand it all. Are you able to install custom overflows in the tank corners or something like that?

Any advice would greatly be appreciated

 

[Ian14]

The seller says the tank has four holes across the back

 

[Luananeko]

The pre-drilled tank just means that it already has the holes that your overflow box would be usually be used to provide. You then have the choice of a closed sump system (which needs no overflow and behaves similar to a gigantic canister filter) or an open sump system (which needs plumbing such as standpipes and baffles similar to what you would have inside an overflow box) added to prevent siphoning all the tank water to the sump).

In either case, no external overflow box is needed, but you would need some of overflow box's equipment internally in the tank if you're going with an open sump system. The reason people prefer drilled tanks even in the case of an open sump is that it eliminates the U tube siphon failure point that overflow boxes can have.

 

[Ian14]

Is one of those a hang on the back system where it uses only the siphon to take water from the tank to the sump? I'd like to do whatever is more simple and most cost efficient. I wish I could just see each of these set ups I'm person and I think it would be a lot easier to understand. How would the closed sump system work exactly with that tank?

 

[Luananeko]

This is basically what an overflow box does....

It makes sure that no more water enters your sump than what the sump pump can put back in your tank. This means that your sump can be open top to increase gas exchange. As long as no air bubbles build up in the U tube siphoning water into the overflow box to break the siphon, you won't have any floods. If your tank is pre-drilled, the system looks like this instead:

The tall drain pipe is there to serve the same purpose as the pipe in the overflow box: to prevent more water entering your sump than the pump can return.

In a closed sump, the sump itself is airtight. It still uses the return pump to put water back into the tank, but there's no other outlet for the water. The sump section is completely sealed, meaning there's no risk of a flood when the water leaving the display tank overfills the sump. The "extra water" is just returned back to the display tank. In this system, it's like the second diagram, but without the tall pipe on the intake, and optionally you don't have to return the water at the top of the display tank. Your intake can be a short pipe just taller than your substrate and same goes for your return pipe.

Does that help?

 

[Ian14]

Yes it does, thanks!

 

[Ian14]

In regards to this, how much money do you think I would spend on the piping and connectors for the sump system? The holes are already drilled, comes with the pump, sump tank. Would this be relatively cheap/simple or is this going to be a lot to do. It comes with a few pipes but I don't think it is everything

 

[Luananeko]

Plumbing is usually fairly cheap... I've only put one sump together myself, but I think I spent under $50 for the pipes, connectors, sealant, etc when I built mine from scratch. I was also doing a pretty complex one, and I didn't have the advantage of a drilled tank like you're looking at. So I would imagine it would be fairly cheap.

 

[Ian14]

I got some more pictures of the drilled holes in the main tank and sump tank. It looks like the sump tank is drilled and has bulkheads in it, why would that be?


Im trying to figure how this whole system would work. I guess I would get and install two over flows inside the tank in 2 of the holes, and then hookup piping connecting it to the sump and then have two pumps to return it through the other two holes, am I right?

 

[Luananeko]

View attachment 222129View attachment 222130I got some more pictures of the drilled holes in the main tank and sump tank. It looks like the sump tank is drilled and has bulkheads in it, why would that be?


Im trying to figure how this whole system would work. I guess I would get and install two over flows inside the tank in 2 of the holes, and then hookup piping connecting it to the sump and then have two pumps to return it through the other two holes, am I right?

If the sump is drilled in the top, it sounds like it's a closed sump... If so, you just need short stand pipes for the 2 intakes in the main tank, not two overflows. Can you ask them if they have pictures of how the tank looked when it was all hooked together so we can see how they had the plumbing previously?

If its not a closed sump, then yes, you would need to install baffles around the holes you're using for the intake (either a central box around the two middle holes, or a box in each corner around the corner ones). The return pipes would also need to be tall enough to break the surface of the tank so as to not create a siphon down to the sump when the pump is off.

 

[Luananeko]

Oh wait, I see the sump pics now. The bottom drills + bulkheads just give you a place to attach a pump external to the sump. Looks like an open sump.

 

[Ian14]

What do you mean? Couldn't I have a pump in the last section if the sump and then a pipe connecting the output of the pipe back up through one of the drilled holes right?

 

[Luananeko]

Yes, that's doable too if you prefer an internal pump. Some folks like using external sump pumps to minimize noise and to avoid heat transference into the water.

 

[Ian14]

Where would the external pump be placed? Is the tank set up to be a closed or open system. Or can I do either with those drilled holes?

 

[Luananeko]

The pump would be installed in-line on the return pipe. So it would go Sump --> bulkhead --> pump --> return pipe. I've never set up a closed system, but basically you'd have to make the lid completely watertight. From what I can see of the lid to the sump, its not.

 

[Ian14]

Gotcha. The sump looks just like an old tank. So the pipe would go through the drilled hole in the end of the sump tank and then outsid it would connect to the pump and it would go back up to the tank?

 

[Luananeko]

Yep, that's how an external pump would fit in if you went that route. You said it came with a pump though, so it likely has the plumbing to connect that in already.

 

[Ian14]

It said the pump is un-opened so I'm not sure. It is a dolphin 1200. Do you know anything about it?

 

[Luananeko]

Not familiar with it, but a quick google search says its a submersible one

 

[Ian14]

The package said was external. Dont think they have made them in a while. Do you reccomend using 2 external pumps and two return pipes and outlets

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