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Overflow Box that I don't understand.

wdickenson

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I have just gotten a new (used) tank with a built in overflow box. First time with this but the setup is a bit odd. The overflow box has multiple chambers which look like this

1588961274203.png


The one on the outside goes straight down into the box where it flows out of one of 3 holes in the back of the tank.
The next one in is a closed box. It doesnt "go" anywhere.
the next chamber is closed also but has a circle cut into the divider. I reached down and that also goes no where.
Then we have an open chamber and the sequence repeats.

What is supposed to go where ? Obviously the 3 "to filters" to to the sump, but what are the other boxes for ?

Thanks
 

steveb

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Can you post a pic?
 
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wdickenson

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Can you post a pic?
Sure but taking pictures of black plastic is a bit of a challenge

Image5 is all 3 chambers ( it just repeats on the other side). Near as I can tell, the one on the near edge is simply a flow through for emergencies. If the grates get blocked up. It has no grate but it is below the lip. Looks like the water flows into the second chamber. Now there is a strip of plastic that looks like it might hold a sponge prefilter. But the lip is way below waterline from the 2nd, to 3rd chamber.
The 3rd chamber (Image 7) has a shelf with a hole cut in it. So the water flows in here and then I have no idea what that is. But.... at the bottom of that is a piece of plastic that seperates the 3rd from the next chamber ( straight down) that forces the water to go down through the hole and back up the other side. Image 3 shows that box, with the panel.

Lousy pictures but the flow of the water seems clear enough but the chamber with the hole is a bit of a head scratcher.

Thank you for looking
 

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Cody

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Just to clarify, this overflow box is built in and doesn’t have holes drill in the bottom of it to go to a sump, correct?
 
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wdickenson

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Correct. No holes other than the 3 sump out. The returns are not built in. They "hang" over the top.
Thank you
 

Cody

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Why in gods name does it have three holes out of the sump returning to the tank? Even with the pics, I don’t understand your built in sump.
 
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wdickenson

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let me rephrase that one.

This is the back of the tank. (image 0). Those 3 holes are what drains TO the sump. Circle is a better picture of the chamber with the hole. Prefilter is the one next to it.

There IS a hole in the bottom of the prefilter but it looks like a drain. It leads into the tank at large. Certainly not a pump

Thanks again
 

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Bullitt519

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One might be for the return? Two drains and one in tank return. Hard to tell with the pictures.
 
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wdickenson

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That was my original thought but all three holes are open to the same space. Which I agree makes no sense
 

steveb

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That was my original thought but all three holes are open to the same space. Which I agree makes no sense
Are the holes large enough for a 4” filter sock?
 
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wdickenson

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Actually yes, they are large enough for a filter sock and now that I look at it, you probably have that absolutely correct. Not the usual arrangement but yeah, thats probably it.

I do have some additional information so I hope this helps. I took pictures of the trickle filter and the output holes line up with the two big ones on the tank(42in apart). Now why I would have a 2 inch hole in the back of the tank for a 1 inch fitting escapes me but lets assume those are the returns. Then the one in the middle would be the downflow to sump. That would seem to be confirmed by the two large pipes I found under the filter media (bigpipe) and the two smaller "return" sized pipes that were hiding there as well.

So if you are all right, this would mean that the two holes on the outside are the inflow to the tank, and I need an elbow to go up and into the tank. So they are not "involved" in the overflow box at all. I'll need two pumps and thats probably prudent anyway. The center hole is the downflow to the sump. The open ended boxes are emergency overflow to protect a blocked grate. The 2nd box is a prefilter (sponge) the 3rd with holes are socks (as Steveb suggested) that would seem to make sense. Massively oversized holes but nothing else logically fits.

Then I just have to figure out what this brute of a protein skimmer since I havent seen this type either !

further comments welcome but I'll call this a success. Thank you for walking me through the right questions and making me go back and look at the right things.
 

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