Overflow Standpipes

Try this... Take a 1" bulkhead and add a 1" pipe full of water and let gravity pull the water through the bulkhead.

Now take they same set up and enlarge the area of water before the 1" bulkhead (1/2 to 2x area). Now let gravity do it's trick and tell me which one moves more water faster, or more volume, in a certain time span.

I may be wrong on this (as my wife tells me I am all the time) but try it and let me know your results.

 

The hardest thing about the durso is managing the amount of air into the system through the top cap.

I recommend you use a small nail and pound it into the cap until it just barely makes a hole you can see light through, and test it on the standpipe.
Then keep making that hole slightly bigger by tapping the nail until the water level holds steady. Took me about 3 iterations of tapping to get it right.

 

Instead of a nail, I have used a drill index and moved from one to the next.

Observation...I'm likely too large now...the smaller the hole, the more siphoning effect I observed...at first, with the smallest hole, the stand pipe will suck air to break the siphon and is very noisy....there was a range of holes where the amount of siphon decreased...then stopped...

While increasing the size of the holes, the sound of sucking air increases through the hole which you are creating. At this point, I have no siphon in either of the two stand pipes. But, I have very good control to balance the flow to the Refugium and DT by adjusting the height of the pipes...BUT, as the wife pointed out, the tank is now noisy...and would I pls. "un-do what ever it is that I did."

So, I'll be using a bit of RTV to plug the hole and start over...easy...

 

I use Ken Stockmans standpipes but stick a needle type airline valve in the cap to regulate the air flow. If the sucking sound gets too loud stick a piece of airline tubing on it and run it out the back of the canopy or make a silencer out of an empty 35mm film can stuffed with a bit of filter floss or a cotton ball and stick it on the end of the tubing.

 

Only problem I keep having with my hole is salt creep. I think I need to increase the length of the pipe leading to the cap to keep water from splashing on it.

 

even with the smallest drill I had, the amount of air getting in was too much, water would rise higher than the hole and then suck air in with the water and create a high pitched whistling noise. Once I switched to the nail and knocked it until right, my water level hovers within a 2 inch margin periodically throughout the day and is very quite, almost noiseless since the water is only dropping about an inch into my overflow.

needle airline valve is a great idea for this pipe. If I need to adjust in the future i'll add one of these and be done with it.

 

quick question....When I make these standpipes, do use the PVC cleaner/primer and glue with them?
Did you guys glue yours or just fit them real tight?

thanks!

 

You'll want to fit them. Never glue something you can see yourself needing to take apart in the future

 

Amen. Never glue them together.

 

Slip fit.
I use all thread x thread bulkheads but for my vertical standpipe I screwed a 1" MIPx slip male adapter into the bulkhead then slip the PVC into that. That way I can remove it for cleaning or adjustments.

Dr. Burgeron, you say your water level can vary as much as 2" over the course of the day? The level in the tank should be rock steady, mine doesn't vary a tenth of an inch if that. Are you trying to control your water height and flow with the overflow? If so this probably is asking for trouble. You want the overflow to take all it can and adjust the height and flow with a ball or gate valve on the outlet of your return pump. The overflow should be totally unrestricted. My overflow box is internal but the water level always stays about half way up the teeth and never changes no matter what I do to the standpipe, other than plug it completely that is.