# Overflow as a return line?



## mel_cp6 (Feb 3, 2009)

Just wondering if anyone has ever tried using the top overflow as a return line to a tank below it. 
Im plannin on building an 8'tank and using one of its overflow as a return line. 
I'm contemplating this to solve a plumbing issue I have due to limited room in my basement.

Thanks


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## mel_cp6 (Feb 3, 2009)

Nothing?


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## iwade4fish (Jan 5, 2009)

i know a thousand ways NOT to make a filter, and that sounds feasible, to me. A pic/drawing helps.


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## mel_cp6 (Feb 3, 2009)

I'm just Planning to use a PVC overflow at the top tank to drain to a bottom tank and will be using exact same PVC size overflow for the bottom to drain to a sump. In theory flow should be identical and i may use a ball valve To control the top one. 
It may not provide a good water movement but only **** and juvies will be in the bottom 50g tank. Plus it will also have a sponge filter and a power head on timer to helP with water movement.

So basically, top tank will drain to a bottom tank 1st before it drains to a sump.


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## iwade4fish (Jan 5, 2009)

ahhh, I see.
2 tanks, one filter.
Man, i've seen too many of my 'in theory' projects go south.
My concern is balance, and flooding a room. It CAN be done, but it doesn't NEED to be done.
Side by side,? yes.
Top and bottom, asking for water on the floor.
just my two cents from YEARS of mistakes.
Give it a shot, it's only water


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## mel_cp6 (Feb 3, 2009)

I'll keep that in my mind.

I actually have all my 3 tanks (125,75&50) connected to one sump but they all have their own PVC overflows. 
I've never tried top draining to a bottom tank before.

But in theory, since both PVC oveflows will be identical, flow should be the same. Btw, these are PVC overflow designed by "thefishguy" and they do not require priming or check valve. So they really have to reason to suddenly stop draining compared to the PVC pretzel overflow design.


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## iwade4fish (Jan 5, 2009)

fishguy makes good things :thumb:


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## zquattrucci (Apr 25, 2012)

dont forget to rember gravity also im sure it is possable but keep a close eye on that baby and the other half wont like all that water on the floor if you mess up


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## mel_cp6 (Feb 3, 2009)

Lol. 
That's why i thought about installing a ball Valve on the top drain just in case It drains faster.


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## zquattrucci (Apr 25, 2012)

i would deffentley do that on both good idea that way you can get it exact make a mark with tape with your water line will be to be able to dile all of them in you laph my mom x let one go and over an hour and a half wile he slept on the couch oppps dude let me tell you i walked in the house and my shoes up to the laces were covered we are talking a carpeted living room lol dude it was like a waterfall swamp room the dang african claw frog and arowana on the floor doing fine him sawing logs crazy day no joke did it 3 different acasions not as bad the rest of the times :lol:


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## lilscoots (Mar 13, 2012)

If the sump is at the same level as the bottom tank you're going to have issues, the flow laterally is very slow compared to vertically. I think you'd be better served running two lines from your pump one to each tank and having an overflow from each tank go back to the sump. Put ball valves on the pump lines to control flow into each tank.


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## mel_cp6 (Feb 3, 2009)

The sump is about is about 6" lower that the other tank from top rims.


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## mightyevil (Oct 23, 2008)

you should be fine as long as the overflows are not restricted and are not leaking.


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## mel_cp6 (Feb 3, 2009)

I'd the bottom overflow can not keep up, I can always add a PVC pretzel overflow to help it drain. 
I'm currently working on the stand now hopefully I'll be able to plumb in 2 weeks.


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## mel_cp6 (Feb 3, 2009)

Just had an idea and was wondering if it would help. 
Im thinking of using a 1.5"-1" bushing or a reducer to help increase flow on the bottom tank. I don't really want to redrill and replace the bulkhead so I thought this will make the bottom drain faster than the top. Therefore eliminatIng or reducing the chance of the bottom tank from flooding if it couldnt keep up. 
I realize that water still has to flow thru the 1" bulkhead before it gets to the 1.5" PVC but it should provide a faster flow.

Do u guys think it's an idea worth pursuing?
Sorry cant provide any pics as my pc is down.


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## zquattrucci (Apr 25, 2012)

how would that work because you have a 1 '' bulkhead be restricted to 1'' of flow


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## mel_cp6 (Feb 3, 2009)

It might be a long shot but I just really need the bottom tank to drain slighty faster than the top or the top drain slightly less than the bottom. Every little bit will help like putting a ball valve on the top tank only. The bottom doesn't need one as I need this tank to drain at full speed.


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## zquattrucci (Apr 25, 2012)

then up your bulkhead size a bit


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## mel_cp6 (Feb 3, 2009)

Everything is all done and problem free. All 3 tanks are draining properly and i used 1 fishguys' overflow and 1 pretzel overflow design for top 75 to drain to the bottom tank. This way if fish goes over the PVC overflow it will not end up in the mechanical box of the sump but end up in the bottom tank. However, fish can still end up in the sump if it's a very small fry. 
the bottom drain has no problem keeping up with the flow since the top tank has two overflow and it gets decided into two and at the same time it is really controlled by how much water is returned to it. I have all the return going full blast to the 125g and the 1/2" return on 75g and there is plenty of water movement and sufficient turnover. The 75 and 50 also has a power head and sponge filter on timer to further increase water movement.

The 125 also has a 1/2 water floor drain and so does the bottom tank. I can actually used the floor drain on the Bottom tank to fully drain the top two tanks when needed. All I have to do is syphon their water to the bottom tank while the floor drain valve is open.

Thanks for all the input btw and everything is running smoothly.


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## zquattrucci (Apr 25, 2012)

lets see some pic then


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## mel_cp6 (Feb 3, 2009)

My pc is down and I don't know how to pics from my IPhone


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## mel_cp6 (Feb 3, 2009)

Well after a week of being in the new set up, I have 2 wild female mobas that are holding. Today is they're 3rd day and I plan to strip at day 10. It must be the new water and clean substrate.


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