Diy overflow design/questions

[rooski]

i want to make a DIY overflow (as storebought overflows are too expensive), and im debating on these 2 designs , and i also have some questions about them.

#1 is from the sticky here

#2 from aquariumlife

pics from different angles
i also plan on having a little overflow box that the intake of the overflows will be in so the surface of the water will pour into the box stirring the water and the overflow will suckup everything.

my main question is how is water regulated through these , say the water level drops below the intake B pipe on overflow #1 then will all the water drain and ill have to start a siphon again ? or will it keep flowing once the pump pumps more water in? (same question for #2 ,which i like more as it uses less pvc and looks cleaner)

im also assuming that wherever the T is on #2 is where the water level will try to even out to, is that correct?

which design would be better, and why?

also im making this for a 110 gal tank , and the return pump will pump about 500 gph at 4' , so what thickness should the pvc overflow be, im thinking 1" is good or should i go for 1.5"?

thanks for reading.

 

[Burko]

"which design would be better, and why?"

The one from the sticky here...

Because its, once primed, a self starting, self stopping, self flow regulating... overflow, not a syphon.

 

[Burko]

"im also assuming that wherever the T is on #2 is where the water level will try to even out to, is that correct?"

Ahhh Ok, now I have joined the dots with the 2 diagrams for No 2...

Yeah, it looks like thats where it will be full flowing.

 

[RODinCALIFORNIA]

you can get nice clean used overflow boxes on ebay shipped for 20.00-25.00 i have bought 8 at those prices and they work great.

 

[KaiserSousay]

"which design would be better, and why?"

The one from the sticky here...

Because its, once primed, a self starting, self stopping, self flow regulating... overflow, not a syphon.

They both self stop and start.