this overflow is either going in a 30g or a 70g. prolly gonna try it on the 30g first to make sure it works. i was wondering since im going to be using a "around 350gph" pump. i made the overflow out of 1-1/2 in pvc. is this to big. can the overflow be to big? will it be a problem running 1-1/2 in at that low of a gph?
diy pvc overflow size
- Thread starter Cholbert
- Start date
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BigJim
Aquarium Advice Addict
As long as the pump has a lower flowrate than the overflow, you're ok. The overflow only lets water out when there's too much. If your pump can outflow your overflow, you'll be filling the tank faster than you can drain it, resulting in floods.
I'd say 1.5" pipe is overkill on your tanks, but it should work.
Cholbert, isn't that pipe somewhere in the 0.5" - 1" range? It doesn't look like any 1.5" PVC I've ever seen.
I'd say 1.5" pipe is overkill on your tanks, but it should work.
Cholbert, isn't that pipe somewhere in the 0.5" - 1" range? It doesn't look like any 1.5" PVC I've ever seen.
ya i think the one in the video is half inch. im actually shopping for a 125g that this might go in. just wanted to build one and get it to work. i was just afraid that if i test it on a 30g that it would lose cyphon or somthing because its such big pipe.
jsoong
Aquarium Advice Addict
Because your siphons are the same size as your main overflow in this design, you might have problem with such large pipes. The water velocity inside the pipes goes down with increasing pipe diameter. At slow water flows, small air bubbles don't get flushed out & get trapped, eventually breaking the siphon.
I had this problem with my DIY. If I use 2x2" siphons (750gph) the water flow is slow enough that I will lose siphon every few days. <Thankfully no flood, as I have 2 siphons ... the other acts as backup.> Now I use 2x 1" an d no problems.
BTW - instead of using all white PVC's, you might consider using a clear section at the top of your siphon, that way you cna see if air is accumulating.
I had this problem with my DIY. If I use 2x2" siphons (750gph) the water flow is slow enough that I will lose siphon every few days. <Thankfully no flood, as I have 2 siphons ... the other acts as backup.> Now I use 2x 1" an d no problems.
BTW - instead of using all white PVC's, you might consider using a clear section at the top of your siphon, that way you cna see if air is accumulating.
