The more holes the better.

Yeah go mad with the holes. The strainers not there to restrict the flow, so the more the better. Also the holes will slowly close up as the algae, tube worms, corraline, etc grows, the more holes you have the less affect this will have. But I wouldn't go too large with them maybe 2-3mm(?), because you have a tap inline restricting your flow if anything large like a snail gets trapped on the tap it will cause the water level in the over flow to rise quickly (I'm sure you know this already). Also don't glue it in place, you need to be able to take it out to clean it, plus if your tap does get blocked you are going need to be able to somehow get to it if the blockage jams.

Also the holes will slowly close up as the algae, tube worms, corraline, etc grows, the more holes you have the less affect this will have

or in my case, valonia :evil: i would go a little larger than 2-3mm, more like 5mm

or in my case, valonia i would go a little larger than 2-3mm, more like 5mm

I would rather have the valonia stuck on the stainer than blocking up the tap restiction.

Go the durso, don't have to worry about this stuff :lol:

You know what, I've had a ball valve running on a full siphon overflow for 4 or 5 years, never cleaned it, it's never clogged. I doubt there is much of anything growing on it. It's in a dark tube with a lot of flow.

Just scraping the bottom of the barrel to find something wrong with a full siphon.

Current hole size is 4.5mm. Will double the number of holes. Also noticed that when I take the standpipe out it doesn't affect the water level, so basically all the restriction is due to the valve.

Also noticed that when I take the standpipe out it doesn't affect the water level, so basically all the restriction is due to the valve

you mean take out the entire length and U section of the standpipe the water level stays near the top? if so, increase the pipe down, too risky. water level should drop to near the bottom of the overflow chamber. with standpipe in, should be halfway (or thereabouts) across the U section.

But that's the way a full siphon works. The pipe should be irrelevant in the matter.

Run the water level higher, to minimise noise. Run it lower if you want more auto adjusting margin.

what do you mean by u section? I'm just saying that the current standpipe is very effective at straining water, so much that it has basically no water flow resistance. 8)

Just scraping the bottom of the barrel to find something wrong with a full siphon.

I have never tried to 'find' anything wrong with full siphon systems, if people want to use them, that is fine by me. All I have done to point out to newbies that might not understand there is a trade off between noise and margin of safety in this choice. As well as the on going adjustments that MIGHT be neccessary.

Don't worry, I think KP understands what's going on and how it works better than most.

The difference in safety margin is negligible, and as far as on-going adjustments I haven't had to other than for major changes to the return system. When set-up properly, they adjust themselves.

That took ages, well we now have 3x the holes

Hopefully that will do it

I have never tried to 'find' anything wrong with full siphon systems, if people want to use them, that is fine by me. All I have done to point out to newbies that might not understand there is a trade off between noise and margin of safety in this choice. As well as the on going adjustments that MIGHT be neccessary

If you set them up right from the start you will never have to adjust them, never.

exactly

full siphons need adjusting occasionally. Its better to have the tap higher for easier access. You can add one to the pipes ypou have there in the overflow.

Seems not all users of siphon systems agree with you. A little bit like claiming durso's aren't quiet but don't make or tune them correcty.

Physics is physics, you can't make a durso as quite as a full siphon because the durso design intentionally introduces air into the overflow.

Layton

apparently reefs durso is silent.

kp I would make those holes bigger, tube worms/corraline algae build up on them so they will bloke them a little. Use a 10mm drill.

Physics is physics, you can't make a durso as quite as a full siphon because the durso design intentionally introduces air into the overflow.

Layton

whats is your point? who said a durso was as quiet as a full siphon? Its a bit like saying something that is so quiet you can't hear it isn't as quiet as something that makes no noise.

Its interesting that you are trying to use physic's to justify this non-arguement yet are happy to make statements like "The difference in safety margin is negligible" when any one who has an understanding of physic's will tell you that there is a huge difference in safety margins between something like my durso (50mm with 40mm bulkhead) that will handle 3-4 time the volume going through it and a full siphon that is adjusted so it only just handles the flow. If you dont believe me I'll double the flow through mine and you double the flow through your's and we'll see who gets wet first.

I'm not going to post on this subject again in KP's thread, unless KP asks, it is pointless going over old ground again, and spoiling a good thread.

10mm is getting a bit close to what can fit through the valve. I'll rip out the valve and actually mearsure it sometime.

If you dont believe me I'll double the flow through mine and you double the flow through your's and we'll see who gets wet first.

Thought you would like that one :lol:

here is a pic

wow its a jungle in there, how long has it been since you cleaned it :lol: :lol:

I hope I can get that much stuff in my display tank

heres what i have. its pretty much idiot proof. it is a ball-valve controlled standpipe with a seperate tank fitting up near the top of the overflow. if the main syphon is restricted, any excess will go down the secondary line and into the sump. the water usually runs under the second line so nothing can get into it under normal conditions to block it. the second line can handle the entire volume of water coming from the return pump on its own. scuse the pic but you get the idea

http://blowfish.co.nz/overflow.JPG

Pic to big, changed to URL, please keep under 100KB