Durso Pipe Question...

WhiteysTA

New member
Ok, I got the breakdown on the DIY Durso pipe, but what I cant figure out is why you are supposed to go from the 1" bulkhead through a bunch of reducers then into the 1 1/4" PVC pipe? I couldnt figure out why, so I just went from the 1" threaded bulkhead to a threaded 1" - 1 1/4" slip and straight into a 1 1/4" PVC pipe. From what I can tell this should increase the flow over what was described on the website. Any thoughts on this?
 
straight from the site:

"My tank has a 1 inch bulkhead on the bottom glass where the water drains out. For this size hole, I recommend you use 1¼ inch PVC for the standpipe. I do not recommend 1½ inch PVC as the larger fittings are much harder to fit inside overflow chambers. And secondly, there is no advantage in 1½ inch over 1¼ inch PVC when dealing with a 1 inch bulkhead -- the bulkhead is the limiting factor for the amount of water that can drain out.

With 1 inch and smaller bulkheads the standpipe PVC diameter needs to be larger than the bulkhead to work correctly. I get a lot of e-mail questions on why this is. Honestly, I'm not sure. Typically if you use 1 inch PVC pipe on a 1 inch bulkhead you get poor results. (Some exceptions with smaller low flow tanks.) Take my word on it and use 1¼ inch PVC pipe."

I went with the recommendation and had zero issues. I figure I was pushing 900-1000 gph with my mag 12 wide open. The limiting factor on why I didn't run wide open was the slots on the mega-flow couldn't handle it. There is a mod on the site for that as well.
 
I look at it this way, sometimes it is what it is and experience matters :D I'm no flow engineer but it works :thumbsup:
 
I think it has something to do with the back pressure. I used a 1" pipe on a 1" bulkhead and it worked fine. Dont forget the vent hole.
 
i always use 1" pipe on 1 inch bulkheads but i use low flow through my sumps. I dont see an advantage to biger pvc if the bulkhead is the limiting factor.
 
I never had the larger sized pipe on any of mine until this 180 I bought from Rena. Either she built them or someone before her.
 
I guess when I do my 58's standpipes I will spend the extra 5 bucks to make both. Run test scenarios, take pictures and put this one to rest. Sometimes a guy's word "Durso" is never enough. :lol: took the time to share his experience and build an informational site. There are a lot of cases of whatever in this hobby. I will do it a certain way because this step doesn't make sense. Yes it might work but you might not realize what added effect you may have introduced. Depending on certain cases because every situation can be different. I pushed more flow than what the recommend was for the supplied standpipe by making a Durso. I felt the Durso would be better to deal with as I would be the one constructing it and not glue where I wanted it to come apart. I have a small one inch durso like pipe in an external overflow currently and that thing sucks in more air and creates more micro-bubbles than my Durso I had in the 90. One inch pipe thru out and external over-flow obviously I can't push as much flow. But I will test this when I get a chance to set things up on the 58. The theory behind the bigger pipe might be the same behind why you go slightly bigger pipe on the inlet of your return pumps. Cavitation/ the disturbance of liquid: the rapid formation and collapse of bubbles in a liquid, caused by the movement of something in the liquid - say bubbles trying to rise while the water tries to fall. The slightly larger pipe would have more water volume to deal with this.

I look at it this way. With the slightly bigger pipe there is more water volume in a chamber ready to push through the limiting factor the bulkhead. With the same size pipe as your bulkhead you have put the limiting factor at the inlet possibly making it more of a suction, less free flowing. Added micro bubbles, vibration, sound, the constant rising and falling of the water volume in your overflow, more salt creep or salt spray. This is a debate right? :D
 
My question was why go from a 1" bulkhead to a 1" PVC then to a 1 1/4" reducer, and finally to a 1 1/4" PVC coupling? I just got a 1" to 1 1/4" reducer and ran 1 1/4" PVC all the way up. I can see that the durso way causes a bottleneck, but I'll be running a ball valve below my bulkhead, so if there is too much flow or not enough backpressure I can adjust it there. Does any of this make sense? Thanks!
 
<a href=showthread.php?s=&postid=12462499#post12462499 target=_blank>Originally posted</a> by ramtheory
This is a debate right? :D

Just because you said it...........Yep. :lol:


I don't know anything about a Durso, so I can't chime in on the topic. But if there's a reason to have a debate with you :D I'm all for it :lol:.
 
<a href=showthread.php?s=&postid=12463461#post12463461 target=_blank>Originally posted</a> by WhiteysTA
My question was why go from a 1" bulkhead to a 1" PVC then to a 1 1/4" reducer, and finally to a 1 1/4" PVC coupling? I just got a 1" to 1 1/4" reducer and ran 1 1/4" PVC all the way up. I can see that the durso way causes a bottleneck, but I'll be running a ball valve below my bulkhead, so if there is too much flow or not enough backpressure I can adjust it there. Does any of this make sense? Thanks!

reducing it down to create more of a funnel effect???
 
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