I need Durso Help!!!! again....

trodder · 02-24-2005, 10:03 PM

Well, here is the deal.... Jerry graciously agreed to swapping my mag 18 for his mag 24. It is on a 58 gallon RR tank. I know what your thinking (way toooooo much flow.) However my sump is in the basement but the tank is upstairs, so I have a ton of head loss. I needed a little more flow (at least a couple more hundred GPH.) I certainly got that in fact I would guess about 400 more GPH give or take. Well that is great and all but the drain in the sump gets bursts every so often causing the level of water in the sump to change quite a bit. My skimmer is very sensitive to level changes so that creates a huge problem for me. Now the level in my overflow box I am able to keep constant so why is it that it won't drain consistantly????? I hope I am making sense but if not feel free to ask questions. The drain size is 3/4" (I'm sure it makes it a little more difficult to tune this thing.) The total drain flow I would say is about 1000GPH or less but I will try to get a better idea soon.

redlion4 · 02-24-2005, 10:14 PM

Is there a valve on the return line? If so, try closing it a bit to restrict the flow and see if that helps eliminate the bursting & water level changes. Not sure what is causing the "bursting", but it sounds like this is a new problem since the pumps were swapped out. It might not be the final solution (bigger dursos if possible?), but it may help with the water level until the problem can be identified and fixed.

Ryan

Skipponator · 02-24-2005, 10:28 PM

How about adjusting the vent? I put a ball valve in the vent so I could adjust it if I ever wanted to change it or the pump.

trodder · 02-24-2005, 11:23 PM

I alreadyu have a adjustable vent on mine. That is how I keep the water level in the overflow box the same. This is what makes it so confusing.

Skipponator · 02-25-2005, 09:25 AM

Your pipe clear of obstruction? Sure you've checked, but sometimes the easiest is forgotten.

kjdeut · 02-25-2005, 12:53 PM

Hey Trodder are you sure your overflow level isn't going up and down at all? Reason Im asking is becuase I have been battling what sounds like the same problem ever since i moved the sump from under my tank into the next room.
After I made the move my overflow would cycle up and down every 5 -10 mins (it varies)whcih would cause the level in the sump to go up and down whcih totally screwed up my auto top-off.
I have rebuilt by Durso, changed the durso vent, increased the size of the drain line to 1 1/2" PVC, and tried venting the line. It is more stable then it was when I first started but it still cycles
Anyways I'm still playing with it trying to get the cycling to stop all together.

Ken

Frogbone · 02-25-2005, 01:04 PM

Why do the overflow levels go up and down ? Do you guys use factory Durso or DIY Durso's ?

What do you guys recommend I use for my 125RR AGA that I am going to set up soon.

Durso, Stockman, DIY etc. , what are known issues and solutions with all those ?

kjdeut · 02-25-2005, 01:11 PM

I have a DIY durso and up untill I moved the sump into the other room I didnt have any problems. I think back pressure is somehow building up in the drain line which slows down the drain so the overflow level goes up. Once the the overflow level is high enough it ovecomes the back pressure and the overflow level goes down.
Wish I knew what was causing it.

Frogbone · 02-25-2005, 02:27 PM

Is the drain "open ended" as in splashing into the sump or do you have it go into a filter or filter box type contraption ?

How many overflows, 1 or 2 ?
What size is your drain pipe and what size is / are your drains from the tank ?

I was looking at the drain capacity from the stand point of "inside area" (as in circle area).

For example, my 1 1/2" drain pipe has 1.767 sq".

I have two 1" drains (stand pipes) coming from the overflows. They are 0.785 sq" each, totaling 1.5705 sq" of drain area.
That potentially leaves about 0.1965 sq" for air to vent the 1 1/2 " drain.
Not very much, huh? Add a bit of backpressure from water not draining freely at the end and I can see water pushing back up in cycles.

Am I onto something here or am I "on something" ????

kjdeut · 02-25-2005, 03:19 PM

In my case I have a 92 gal RR corner tank with one overflow. Originally it had a 1" PVC drain line that I increased to 1 1/2 " when trying to take care of the cycling. The drain line flows freely into a 29gal sump with the bottom of the drian line about even with the surface of the water. That is why Im really stumped as to where the back pressure may be coming from. I even put in a vent in the drain line about 8 inches from the end so any air trapped could escape, but either that wasnt the problem or I placed the vent in the wrong place. The standpipe is the only piece of the drain system that I havent increased the size of. I used the plans and the specs on the durso site to build my standpipe.

Ken

David Grigor · 02-25-2005, 04:18 PM

I am pretty positive, the design of the durso itself it the root cause. It's probably happening with every durso setup but because the distance for most of us is only a few feet we don't notice.

It's next to impossible to set the air precisely to the exact amount needed therefore there is a small amount of siphon like flushing going on ( even the most slight ) is probably being amplified because of the distance.....

trodder · 02-25-2005, 09:41 PM

I would agree with David on that. I did check for obstructions and it is all clear. I am pretty sure that the overflow box level is remaining constant. I think the distance with the added flow may be cause. Ken one thing I did when I first set this up to cure the same issue I am having now is to set up a durso standpipe where it drains.. I also have just a wide open vent that comes off the drain line about 5 feet before the drain. Basically the vent is a T that has a 6 to 8" tall piece of pvc that comes out the top of the T. That combined with the durso at the drain stopped any and all flushing until now that I have added flow. The only thing I have changed right now is I capped that vent with a cap with a small hole and that seemed to make it a little better. I think is what it is doing now is that every once in a while you can hear it suck in air through that vent I capped, and then it stopps. When it does that it "flushing" but it slows the flushing enough for it to back up the draining a little so that the level stays more constant and making the level change far less noticable... I have no idea why but I am not going to change it unless someone comes up with something good or some type of solid explination why it is doing what it is doing and how to fix it. Anyway the reason why I agree with David is the more I think about it the drain is split and to the left is the drain with the Durso going into the main partition of the sump and where it drains to the right it goes freely into the refugium (with flow controlled by a valve.) Before if I watched the flow coming out in to the refuge the flow would increase and decrease every minute or two, but I did not ever notice it in the main compartment. Now I amplified that with the added flow.