? about the diy overflow

[brianhellno]

wassup brothers!
will it work?

peace

To be honest I'm not sure if that will work or not. Without a U bend in the fish tank to make the "overflow" portion it doesn't look like it will be able to pull water up over the edge of the tank because it would need to rely a pure closed syphon and with that opening there it won't be able to do it. Not to mention you want an overflow not a syphon. If you add another U bend in the tank similar to the one outside the tank you should be in business. Keep in mind I'm not 100 percent sure but I'm fairly certain that I'm right. Hopefully someone else will chime in and give some more info.

 

[brianhellno]

My overflow keeps loosing syphon.. not sure if it has something to do with how I start it or the size.. I'll go through my whole setup just so that somebody may understand what's going on..

I have the skimming type pvc syphon explained in the 101 thread, I built mine out of 1.5".
In my sump is a RIO 2100 pumping into 1" pvc although it gets bottlenecked to go into a UV filter at 1/2" flex tube. This goes up to the oppisite side of the tank of the overflow in a 1" pvc with holes every so often.
My tank is 180 gallon.

The way I start the syphon (not sure really how I should given size) is stick a hose into the overflow and turn it on with my hand held tight around it so all the water goes into it, seems to work. has pretty good suction after that. Only problem is, I've crafted a sort of grid out of a pvc cap and dremmel (love that dremmel) that will keep the fish from jumping into the overflow. Once the syphon is started I put that on the pipe and the syphon weekens significantly, after awhile it's not putting as much water in the sump as my pump is putting in the tank, the water flows over the overflow, then syphoning stops..

!!!

hmmmm, the only thing I can think of is there is air getting in the system somehow. Have you cemented the pvc pipes together with pvc primer and glue? Also how long does it take before it starts to lose syphon?

I'm not sure what the effects could be if you don't get all of the air out of the U bend that runs over the top of the tank. It might be possible that it could expand from becoming stagnant and that could slow down your overflow. I'm just thinking aloud so I don't know how true or not that could possibly be so I'm definitely going with air is getting into the system somehow.

 

[KoiGorgon]

hmmmm, the only thing I can think of is there is air getting in the system somehow. Have you cemented the pvc pipes together with pvc primer and glue? Also how long does it take before it starts to lose syphon?

I'm not sure what the effects could be if you don't get all of the air out of the U bend that runs over the top of the tank. It might be possible that it could expand from becoming stagnant and that could slow down your overflow. I'm just thinking aloud so I don't know how true or not that could possibly be so I'm definitely going with air is getting into the system somehow.

I was thinking air as well. Didn't think about pvc primer and glue.. (total newb to pvc in general) I think I may have seen some pvc putty at home depot, can I just kinda smear that along all of the seams? That way I wouldn't have to disconnect the whole thing.. just tryin to work smarter, not harder.

 

[brianhellno]

I was thinking air as well. Didn't think about pvc primer and glue.. (total newb to pvc in general) I think I may have seen some pvc putty at home depot, can I just kinda smear that along all of the seams? That way I wouldn't have to disconnect the whole thing.. just tryin to work smarter, not harder.

I'm not really sure if PCV putty will work or not. I've never worked with it before so I really can't comment how effective it would be. As far as working smarter not harder, personally I would use primer and glue and set everything together good and firm and let it sit overnight. I only say this because I don't know how good PVC putty is and I would be afraid that it might not form a good seal or it might not be good for this application. As far as primer and glue goes I know its a bit more of a PITA but if done properly its a guarantee.

 

[KoiGorgon]

Alright.. So I've primed and glued all of the joints over the last couple of days and the overflow is now sitting in my tank. I tried to start it up with a hose and it didn't work at all. didn't even start to syphon like it did before. The water level is about a half an inch above the pipe just to have something for it to suck and I've been holding the hose in the pipe for about 20-30 seconds to make sure enough is flowing through it to suffeciently start the syphon... I'm not sure if I'm starting it right at all.

What is the best way to start the syphon on these overflows?
and, if I'm doing it correctly, why is my syphon still not working?

please help me and help my beautiful fishies have a larger home to swim in! thank you


EDIT:: So, I looked at the 101 and I think I understand a little bit better.. if I fill the system at the uptube on the outside of the tank while holding the bottom closed it should prime it that way, right? then it should run smooth?

 

[bitteraspects]

do you have the check valve installed?
you can fill both sides of the overflow, then suck the airline connected to the check valve until only water comes out.

i just use a ball valve to close the sump end of the overflow and suck the last verticle pipe until the overflow is full of water, then open the ball valve. (you still need to remove the excess air via the check valve to get it flowing properly)

 

[bitteraspects]

wassup brothers!
will it work?

peace

maybe not exactly the way its drawn, but it will work. you will probably need to drop the "T" connector a couple of inches. it takes a little experimenting, but it can work.
also, this type of overflow uses a horizontal flow rate rather than vertical flow rate, so it runs slower than a regular PVC overflow. you will either need to use a larger diameter pipe, or a smaller return pump.

 

[KoiGorgon]

do you have the check valve installed?
you can fill both sides of the overflow, then suck the airline connected to the check valve until only water comes out.

i just use a ball valve to close the sump end of the overflow and suck the last verticle pipe until the overflow is full of water, then open the ball valve. (you still need to remove the excess air via the check valve to get it flowing properly)

Confession: I don't have the check valve installed... I don't even know where to get one. Where would I find such a thing?

other note: Probly should install the ball valve as well.. there goes another couple o days, assuming I can get somebody to jump my car.. went outside today to start it up and not even a click...

 

[fishyreview]

If you don't have the checkvalve, you can submerge the whole overflow in your tank and rotate it to get the air out. Then put pvc caps (not glued) temporarily on the overflow hole and vent hole and use your hand or somehow cap the tee that goes to your sump. Position your assembly on the back of the tank, attach to your sump, remove the caps and you should be good to go if you got all the air out. I've built 2 of these in the last few days and that worked for me.

 

[KoiGorgon]

If you don't have the checkvalve, you can submerge the whole overflow in your tank and rotate it to get the air out. Then put pvc caps (not glued) temporarily on the overflow hole and vent hole and use your hand or somehow cap the tee that goes to your sump. Position your assembly on the back of the tank, attach to your sump, remove the caps and you should be good to go if you got all the air out. I've built 2 of these in the last few days and that worked for me.

Won't work.. can't take the assembly out of the tank now that it's all glued together.. had to glue a couple of pieces after it was in place. the PVC pipe itself barely fits in the hole that was cut for it, the fittings will not go through. Looks nice, function is hard though. It'll be worth it in the end.