# making a semi-fish room! question about PVC overflows



## BirdFish (Apr 27, 2009)

so have finally got a few tanks in the same location and would like to make one big filtration system with PVC overflows and a sump. I feel like I have the design and I even have one overflow working perfectly, however I cannot get the second to work. built it exactly the same way, have aquarium check valve in place, but there is still air in the top. cant figure out why. ( I would post pics, if anyone could tell me how to, cant figure that out either .

any secret tips that I am missing....


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## KaiserSousay (Nov 2, 2008)

*one overflow working perfectly, however I cannot get the second to work*. built it exactly the same way 
Can`t happen :-? 
Either they both work, or they both don`t.
Usually a detail missed that causes the bulk of the greif.


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## BirdFish (Apr 27, 2009)

actually it can happen... but thanks for the loads of help.....

to everyone else- my question. is there a small detail that just "fell into place' in the first one that didnt from the second... 
specifically where the check valve is placed, ot the hight of it, in my very first plan, the lower end of the of the valve was a few cm below the top of the inside rim of the pipe. obviously air will be at the top of the tube so i rigged it to where the bottom hole is level with the top of the pipe... may have screwed up there...

second possibilty, hight of the device, some rule about hight and placement that I missed.

any help would be appreciated. thanks


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## PfunMo (Jul 30, 2009)

I'll tell you about my simple dumb stunt. Not to imply that you have done the same.  
If you happen to have a syphon or pipe located where bubbles from an airstone go up---- It can screw with your mind. :lol:

Works for a while but stops when you turn your head.


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## BirdFish (Apr 27, 2009)

Thanks for the idea, but no bubbles in the tank... Thanks though


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## Mcdaphnia (Dec 16, 2003)

Sometimes it takes a powerhead to blow the air out. Sometimes there is a leak somewhere in the seams. It can be waterproof but not airproof. You could paint the seams with a sealer and see if that helps. If there is a slow air leak, blowing out the air with a powerhead will only be a very temporay fix.


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## auratum (Jul 6, 2006)

BirdFish,

Pictures would really help the process of troubleshooting... Here is the directions on how to post photos:

http://www.cichlid-forum.com/phpBB/view ... hp?t=21085

Two things I have had trouble with - I have 5 PVC overflows running - 1 x 3/4" & 4 x 1-1/2". The biggest problem I had was where the air check valve goes into the PVC - I just drilled the hole a little too small and press fit the tapered check valve. This on occasion needs to be pushed in further as it leaks. The other thing was how I built the strainer inside the tank - there needs to be a place for them to "suck air" to break vacuum and if the holes are too small at this point, it makes small bubbles that can be entrained with the water and overtime break vacuum. If you can't get it to even start then you got an air leak somewhere you need to find and fix as Mcdaphnia pointed out.


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## BirdFish (Apr 27, 2009)

Thanks for the tips. I think yall may be on to something. I have not glued/cemented anything because I wanted to make sure it worked. The second one is leaking water at some of the joints, so the whole air leak is possible. The thing will start, but eventually quit, so air leak makes sense.

I think forcing water with the pump at first is a good call too.

Working on pics, I made a photobucket account, will work on getting them on here.


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## KaiserSousay (Nov 2, 2008)

*



actually it can happen... but thanks for the loads of help.....

Click to expand...

 *
1...I guess my understanding of "exactly the same" differs from yours
2...Your welcome. Even if you didn`t care for my answer, it got you looking to what was different between the 2 units, eh?




> glued/cemented anything because I wanted to make sure it worked. The second one is leaking water at some of the joints, so the whole air leak is possible. The thing will start, but eventually quit, so air leak makes sense.


 
As I said before, your problem is in a detail you missed, between "pretzel"#1, which works, and "pretzel"#2, which does not.
90% of pretzel problems involve poor pipe connections, allowing the unit to suck air, the remainder of problems are due to poor design.


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## BirdFish (Apr 27, 2009)

"90% of pretzel problems involve poor pipe connections, allowing the unit to suck air, the remainder of problems are due to poor design"

you see, this was helpful.

"you just missed a detail"

not helpful...

I am going to try and cement the tubes together to try and get out some air leaks.

anyone have any suggestions for what kind of adhesive to use??


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## Mcdaphnia (Dec 16, 2003)

Oatey is a good brand of pipe cement. Pick the right type for the type of pipe you used, or if more than one type of plastic pipe, use the all-purpose cement.


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## PfunMo (Jul 30, 2009)

Sounds like you may be new to the PVC world. I'll throw out some hints that I know help. For straight PVC just plain glue for PVC is slightly cheaper. I usually buy the all purpose as I tend to use several different types of pipe. When you cut it, cut as straight across as you can. No big deal but helps. I find a table saw is nice for this. Once cut, Hold sandpaper in your hand and run the pipe round and round in the palm of your hand to smooth the edges and to take the shine off the glue surface. If it is cold or the pipe is old and dirty, cleaner and primer are a bit of insurance but not usually needed. After you sand but before glue, test fit them to make sure they bottom out well. Put glue around each end that goes together, not just one to be pushed into the other. As you fit them do it rapidly as the glue starts to set almost immediately. As you push them together, rotate one so that any glue will be spread inside the joint. Do this just for a short but stop before the glue does it's thing. Don't break the joint while it is trying to set. Depending on pipe size hold them together for a bit. They can develop pressure and back off. Biggest thing is do it away from flames and don't sniff the cork too much. 

If you knew all this-- beg pardon. It may help others who don't. :thumb:


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## BirdFish (Apr 27, 2009)

you are correct... new to PVC. that was a great explanation. thanks for that. would not have done all that if not educated on it. thanks again.

have glued my pipes. will see if they work shortly.


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## BirdFish (Apr 27, 2009)

Works!!! Were all good! I guess it was the small air leak. Also had some problems with more water coming in than out. But got that fixed as well. Thanks guys for all your help!


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## BirdFish (Apr 27, 2009)

also lesson learned about 'rate limiting factor in flow' I thought my pumps would be rate limiting factor since i got a 345hsp for sale with about a 3-4 ft height for the water to come up.

i used 1/2 in PCV for 2 55g, thinking my might even need 2 pumps, but actually i had to split the hose and put the pump on the lowest flow rate to match the water coming out with the water coming in. I think im gonna get enought flow to maybe have 100g pher hour for each tank, not ideal I know, but i dont have a huge bio load so i think it will work.

next is my 90g. thinking about 1in PVC for that.... any suggestions


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## redblufffishguy (Jul 16, 2009)

1 suggestion......get the tank drilled and add a bulkhead. it works so much easier and without any worries of the tank accidentally draining.

Just an idea!


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## BirdFish (Apr 27, 2009)

I would actually prefer that, but kinda scared about busting the tank. Never drilled glass before... Any advice on actually how to would be appreciated...


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## redblufffishguy (Jul 16, 2009)

take it to a glass shop. it usually take the about 15 minutes per hole (if they have time to do it whil you wait)

HOWEVER, make 100% sure the tank is not tempered. If you arent sure, don't try to drill it. I know for sure that ALL-Glass aquariums ARE tempered. Most of the time there will have been stickers all over the place telling you whether or not the glass is tempered.


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## Deeda (Oct 12, 2012)

Only some Aqueon (All-Glass) aquariums are tempered - http://www.aqueonproducts.com/assets/011/19784.pdf.

You can usually check the manufacturers' website to see the specifications on the tanks. It may be difficult to find sometimes so you may have to search or email them.


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## redblufffishguy (Jul 16, 2009)

True but the chance of getting a tank from All-Glass that is not tepmered, from a LFS, is unlikely. that's why i said what i said.


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