over flow pipe

[big_ben102000]

hi, i am using the old kinda fish tank ... no build in overflow. currently using 2 pumps to pump water in and out of the sump. i was wondering this overflow pipes.. they do need a regulatory valve to control water flow right ? as in like so the amount of water going in and out will be the same. correct me if i am wrong ..

please enlightenment me haha ... my two pumps giving me a headache ... have to adjust of the valve every once in a while ..

[rogersoh]

once i remove my end cap, the flowrate is greatly REDUCED by 50% or more!

i try many methods from taping up the end with only millimetres of openings

but still the flowrate is the same! (SLOW) no matter the hole is big or small!

hence my pump  (input) is drawing water faster then the output..

I also face the same problem as your when I drill a hole or remove the end cap.

I solved it by connecting a tubing from the hole to the tank water and to prevent it from siphoning the tank dry I only extend it within 2 cm of the water level.

This way the flowrate is not reduced and the overflow can also restart after the return pump failure. This is the win-win solution.

[rogersoh]

currently using 2 pumps to pump water in and out of the sump. i was wondering this overflow pipes.. they do need a regulatory valve to control water flow right ? as in like so the amount of water going in and out will be the same.

You will need a overflow compartment. As long the return pump flowrate is lower than the maximum flowrate of the overflow piping system, the water level in the overflow compartmetn will drop until the equivalent is reach. After that the flowrate in and out of the tank will be the same.

Hope this answer your question.

[jun]

16mm will be too small, that's why you got a small flow rate when replace the end cap with a drilled one. suggest you change the piping size.

as a rough gauge: 3FT tank uses 20mm piping 4FT tank uses 25mm piping.

you have to replace the end cap with a drilled one inorder for the overflow to be able to auto-restart. you have to play ard with the skimmer with the water level and the drilled hole size.

if the hole is too small, air cannot enter the pipe as fast to maintain your siphon, the overflow cannot restart by itself.

if drill the hole on the side (on the cap together wif the pipe) juz lik Jireh overflow pipe. then we can adjust the size of the hole juz by turing the cap. is this a much better idea?

[searching4dan]

if drill the hole on the side (on the cap together wif the pipe) juz lik Jireh overflow pipe. then we can adjust the size of the hole juz by turing the cap. is this a much better idea?

sounds like an itelligent idea?

lol! myb u can try it out? let us noe??

i spent quite alot on all the PVC pipings aly, cuz i trial and error..

change from 16mm to 25mm,

all the elbows joints, T joints, end caps cost me quite abit! haha..

the bigger in size, the more expensive it is..

BUT Now i using an i-box.. problem solved!

sure restart on its own! no need worry sump flood or main tank dry!

however i suggest u install a ball valve @ the discharge pipe to regulate the flowrate and also a non-return valve @ ur pump towards ur main tank

!

[femunu]

sounds like an itelligent idea?

lol! myb u can try it out? let us noe??

i spent quite alot on all the PVC pipings aly, cuz i trial and error..

change from 16mm to 25mm,

all the elbows joints, T joints, end caps cost me quite abit! haha..

the bigger in size, the more expensive it is..

BUT Now i using an i-box.. problem solved!

sure restart on its own! no need worry sump flood or main tank dry!

however i suggest u install a ball valve @ the discharge pipe to regulate the flowrate and also a non-return valve @ ur pump towards ur main tank

!

i have my tank drilled at the bottom. and its working fine for me, but i need to help a friend of mine who dont want to drill a hole on the tank. im interested in lettin him try ur way. mind posting ur end product? if possible with da dimensions too. thanks in advance.

BTW will the air tube we use is big enough for the end?? just a guess!!

[big_ben102000]

oh .. thanks rogerson for the reply ! enlighten

[searching4dan]

umm...femunu

who are u asking??

me??..

[jun]

wat the correct hole size for the end cap? i dun wana trial and error.... the end cap is not cheap...anyone can let mi koe ?

[rogersoh]

wat the correct hole size for the end cap? i dun wana trial and error.... the end cap is not cheap...anyone can let mi koe ?

Hi Jun

It is very difficulties to give estimate on the hole size.

I would recommend using the air tube in the hole method in my previous post at http://www.sgreefclub.com/forum/index.php?...ndpost&p=568018

The reason why it is difficult to estimate the size of the hole requires is that we would want the vent tube to be as low pressure as possible (preferly vaccum) but we also want to break the siphon when the return pump fails to operates. If you want to use the hole method I would suggest to use the smallest hole that you can drill maybe less than 1 mm diameter. Then you test whether it can break the siphon when the return pump stop. If not then increase the size of the hole.

Using the air tubing method back to the sump is a better alternative as the flowrate will reduce immediately when the water level drop below the tube opening and increase again once it is cover.

[jun]

Hi Jun

It is very difficulties to give estimate on the hole size.

I would recommend using the air tube in the hole method in my previous post at http://www.sgreefclub.com/forum/index.php?...ndpost&p=568018

The reason why it is difficult to estimate the size of the hole requires is that we would want the vent tube to be as low pressure as possible (preferly vaccum) but we also want to break the siphon when the return pump fails to operates. If you want to use the hole method I would suggest to use the smallest hole that you can drill maybe less than 1 mm diameter. Then you test whether it can break the siphon when the return pump stop. If not then increase the size of the hole.

Using the air tubing method back to the sump is a better alternative as the flowrate will reduce immediately when the water level drop below the tube opening and increase again once it is cover.

hi roger.... can explain more on the air tubing method ?? sorry....dun reali quite understand. you hav more photos on it ??

thanks

[Seng]

There wont be a need for tube or cap if a ball valve is added to the overflow pipe. The flowrate can be altered to suit the return pump rate by adjusting the ball valve. The ###### sound can also be reduced by adjusting the ball valve as the sound arises when the rate of water being siphoned from the pipe is higher than the rate of water entering the pipe from the main tank.

The flow will stop when water level is below the strainer in the next pic, and restart again when water level increases. This set up had served me well over the past 2 years without failing.

[Seng]

The strainer is a seperate piece to collect dust and other particles from the surface of the water. And so that the suction will not affect my sand bed. Instead of permanently fixing it, used the twister wire to fix it instead.

Just to let anyone interested, will be selling off this overflow pipe and wat ever PVC joints and stuff i have for $40 as i am quiting this hobby liao.

[jun]

There wont be a need for tube or cap if a ball valve is added to the overflow pipe. The flowrate can be altered to suit the return pump rate by adjusting the ball valve. The ###### sound can also be reduced by adjusting the ball valve as the sound arises when the rate of water being siphoned from the pipe is higher than the rate of water entering the pipe from the main tank.

The flow will stop when water level is below the strainer in the next pic, and restart again when water level increases. This set up had served me well over the past 2 years without failing.

hmm...how do u explain ur restert of flow when there is no end cap?

[rogersoh]

.. can explain more on the air tubing method ?? sorry....dun reali quite understand. you hav more photos on it ??

thanks

This is how I connect the tubing back to the overflow chamber. I am using the big tubing because I got some extra length left. You can change it to normal air line tubing.

[Seng]

hmm...how do u explain ur restert of flow when there is no end cap?

[jun]

i felt tat by installin a ball valve to the outflow.....will reduce the flow even when the valve is fully open.....coz the hole inside the ball valve is much smaller than the pipe size although the ball valve size is the same as the pipe size......do u guys realise???

[Seng]

i felt tat by installin a ball valve to the outflow.....will reduce the flow even when the valve is fully open.....coz the hole inside the ball valve is much smaller than the pipe size although the ball valve size is the same as the pipe size......do u guys realise???

In regards to this, if i remember correctly, the ball valve is 20mm means that the inner diameter of the valve is same as the pipe. Though can remember liao since i glued it up more than 1 year back.

In any case, depends on wat rate you want your return pump to be. Mine is ok for 1200l/hr (wif half closed valve) which is ok for my 3ft. Internal circulation i use 2 SEIO rather than relying on return pump.