TOTW 6-01-05 Durso Standpipe problems.

[Rook]

Well, I have the new tank up, but not running I have the plumbing setup and it does not leak But it does not work properly either I have a Durso style stand pipe and I am having the "flushing effect" mentioned on his website that I cannot get to go away.

Here is what I have.

I have a 90 gallon glass tank with an overflow box that is 5x8x5. The overflow has a 1 1/2 inch bulkhead for the drain and a 1 1/2 inch pvc durso style drain pipe. A 1 inch return is also in the overflow. (The large drain is because I hope to have a large turnover from the sump.) The drain pipe drains into the basement into my basement sump. It falls about 3 1/2 feet using a slight slope with spa-flex, then from two 45 unions it goes horizontal about 25 feet to the sump room. The 25 feet horizontal I have been playing with to try and get it to slope properly. At the end if falls about 8 feet using one 45 union and spa-flex with a small negative slope. At the very end I have a T union that sits about 1" under the water.

I have been trying to adjust the slope of the 25 feet horizontal run, either increasing or decreasing the slope with no help. I cannot figure out what I am doing wrong. Do you have any advice on what I could be doing wrong? I have a hole of 5/64 in the end cap on the stand pipe. I considered making that larger but the website indicated that was not the problem with the "flushing effect." Any advice at all would be greatly appreciated.

[Reefland]

Rook,

Typically when flushing occurs it is everything to do with the hole IME. With everything running, do you experience anything different if the hole is totally covered (with your finger)? I think you will find that the flushing effect doesn't really differ and will need a slightly larger hole. Go ahead and open it up a bit and see what happens.

[Rook]

I tried to plug the hole with my finger and there was no change at all. The flushing still happened at about the same rate. The current hole is 5/64 ths. I was considering going one size bigger to see if that helps.

[Reefland]

I would just put a second hole of 5/64th in the cap to see what happens. I am pretty sure you'll notice a change if there was no change when you covered the hole.

[Rook]

You suggest a second hole, as opposed to making a larger hole? Any reason why?

[Reefland]

No specific reason other than 2-3 smaller holes are easier to control than 1 larger hole. If you make 3 holes and it is too much, it is easy to cover 1 of the holes with a piece of tape instead of having to partially cover 1 larger hole.

[Rook]

Okay, thanks. I will try it out tonight.

[Rook]

Well, I have tried to play with the hole size, going from 1/64th upto several 1/8 inch holes. Eventually, the flushing motion stopped, but there were so many holes that there was a loud gurgling sound. Thus, I don't think it is the hole size.

I was thinking that part of the problem may be that I have a pretty straight 4" vertical drop, which cuts pretty quickly with two 45 elbows to the 25 foot horizontal. The fast rush of the vertical drop to the sudden horizontal could be causing the back pressure and thus the problem.

But, if this is the problem, how do I fix it? And, is this the problem?

The horizontal is slopping about 2" over the 25 feet and then there is a pretty vertical drop about 8 feet to the sump.

[scubadude]

But, if this is the problem, how do I fix it? And, is this the problem?

So how many GPH are you pushing through this roller coaster of plumbing? I realize you calculated for lots of flow through the sump as stated in your previous post but your gonna get some bumps, and hiccups with that kind of setup if you are anywhere close to the max for GPH. The only thing you really could do is oversize your pipes where it T's, and thereafter. I think you have "Head" caused from wall restriction

[Rook]

Well, I am running a Panworlds 250 pump rated for 1900 gph. But I have a lot of head loss and expected to run about 1200 gph through the overflow. However, I was only running about 1/3 of the water through the overflow thus far by diverting 2/3rds through a split shortly after the pump.

Last night while thinking about this and the fact that I am not really running a ton of water through the overflow it made me wonder if the problem is due to the size of the pvc or not. 1 1/2" should be able to handle the water flow, I would think.

[Reefland]

So the noise is simply from the water flowing through the drain pipe? I think 1.5" pipe is plenty large enough.

[Rook]

No, it is definately make the "flushing effect" where the water level raises high, stays for a bit, then suddenly and forcefully rushes lower and makes a loud flusing gurgling sound. When I completely close all the holes, the water level drops very low and makes a loud gurgling sound. With between a 1/64th hole and upto several 1/8th holes the flushing effect happens. After several 1/8 holes the flushing motion stops, but with so many large holes (I'm talking maybe ten holes) so much air get through and it makes a loud constant gurgling sound.

So, I think there is head resistence being created somewhere. I was advised to go with 2" pipe from the end of the first vertical drop to give more room for water flow. I guess I can try it since I am not sure what else to do but I'm not optimistic it will help, since as I said I am not pushing a large volume of water through it. Maybe 600 gph.

[Reefland]

If the flushing stops with the holes I would say that the lack of air is definitely your problem with the flushing, attacking the other noise is a different story.

[Rook]

Do you know where I can get an air value to put on the standpipe to help dial in the air flow? I will try at Home Depot, but I am not sure where to even start looking.

[Reefland]

You might just try a large needle valve? I looked at local stores with no luck, I had to go to www.usplastics.com for one; look for SMS Needle Valve.

[Randy]

This may sound strange but I think this is the problem. You’re just getting too much flow for the 1 durso to handle. I would suggest 2 durso standpipes. In many cases you won’t have enough room to install 2 complete standpipes inside of your overflow; so what I am proposing is that you install the majority of the durso outside of your overflow and only the portion that the water enters through should be on the inside. This gives you enough room on the interior for 2 siphon tubes instead of just 1. This gives you more stability, higher water flow rate, and should distribute the same amount of flow through 2 dursos instead of cramming all of that water through just 1.

When you use a durso at its maximum capacity it will make a solid column of water down to the sump. Since your sump is so far away from the tank’s water level it creates a massive amount of down flow which overwhelms the single durso, which creates the sucking sound.

[Constructor]

I just wanted to give my two cents experience here. I have not been able to explain the why behind this but your return line must be one size smaller than your standpipe. In my past experience I have solved this problem in two steps.
First increase the size of you standpipe or reduce the size of your return plumbing. Second drill a hole in the top of the standpipe large enough to fit an airline into snugly. Make sure the airline is long enough to extend from the cap down into your return plumbing. To adjust start with the airline fully inserted and pull it out 1/8" at a time in 3 to 4 minute intervals until flushing stops. I hope this helps you out.
P.S.
If you use flexible tubing of any kind make sure there are no kinks or restrictions or you will never correct the problem.

[Randy]

Constructor,

That's a good idea. I have never heard of doing that before.

[Constructor]

It takes a little patience to fine tune but it has worked for me every time.

[Rook]

Well, for the most part I got it fixed. That long horizontal line was really giving me some problems. In the end, I had to reduce the durso to 1 1/4" pipe, which drains into 1 1/2" pipe. Which then is increased to 2" pipe at a 90 elbow and for the rest of the horizontal piping. I also used Constructor's idea, my LFS gave me that idea before I saw it here though. The flushing is at a bare minimum with only a little rush of air sound every now an then and once in a great while it will actually flush. I've had to really play with the placment of the air line in the durso and the slope of the horizontal run to get this far. I don't think I can get it silent, but this is much better.