Closed Loop Circulation and Wiers with Durso's
- Thread starter Mouse
- Start date
It won't work unless the water level behind the wier (in the overflow chamber, I presume) is high enough above the actual inlet for the closed loop. Otherwise, you will suck air into the closed loop.
I will be using such a design for my new tank. I have 4 bulkheads drilled in the bottom of the tank in overflow chamber (behind the partition/wier). 2 of these will have strainers only and will feed the closed loops. The other 2, which will feed my sump, will use Durso/Stockman standpipes. The water level in the overflow chamber will be maintained at the top the standpipes, which in my case, will be around 30" above the inlets for the closed loops (the tank will be 36" tall). Of course, I have not set this system up yet, so I cannot prove that it will work as intended, but I do not anticipate any problems.
I will be using such a design for my new tank. I have 4 bulkheads drilled in the bottom of the tank in overflow chamber (behind the partition/wier). 2 of these will have strainers only and will feed the closed loops. The other 2, which will feed my sump, will use Durso/Stockman standpipes. The water level in the overflow chamber will be maintained at the top the standpipes, which in my case, will be around 30" above the inlets for the closed loops (the tank will be 36" tall). Of course, I have not set this system up yet, so I cannot prove that it will work as intended, but I do not anticipate any problems.
Nice setup Milzy,
I was thinking about having two wiers either side of the rear corners of the tank, each with durso's. I was also going to put bulkheads into the bottom next to the durso's for the Closed Loop. I suppose these would be as tall as i could make them without them going above the Durso's, id probably leave about 10inches of water above them just to be sure, but i could alter the length of the pipes as much as i wanted. My concern was more to do withthe ammount of water that would be flowingover the combs at the top of the wiers. Running the sump alone would be about 500GPH, so that devided by two is 250GPH. But with the closed loops circulating over the wiers as well, that would be another 1500GPH over each wier, thats allot of water. And i was concerned that the wiers would have to be huge, allmost the width of the tank to handle it?????
What do you think. What size would a wier have to be to handle an intermitant maximum flow of 1750gph.
I was thinking about having two wiers either side of the rear corners of the tank, each with durso's. I was also going to put bulkheads into the bottom next to the durso's for the Closed Loop. I suppose these would be as tall as i could make them without them going above the Durso's, id probably leave about 10inches of water above them just to be sure, but i could alter the length of the pipes as much as i wanted. My concern was more to do withthe ammount of water that would be flowingover the combs at the top of the wiers. Running the sump alone would be about 500GPH, so that devided by two is 250GPH. But with the closed loops circulating over the wiers as well, that would be another 1500GPH over each wier, thats allot of water. And i was concerned that the wiers would have to be huge, allmost the width of the tank to handle it?????
What do you think. What size would a wier have to be to handle an intermitant maximum flow of 1750gph.
Two comments.
First, I would not use standpipes, even short ones, for your closed loop inlets. If the main pumps ever quit (or when you shut them down), the closed loops will continue to draw water from the overflow chamber until an equilibrium is met, which will be somewhere between the top of your sump standpipes and the top of the closed loop inlets. If you don't have enough distance (or water) between these, you may end up sucking the overflow dry.
As far as the size of the wier/partition goes, I don't think it needs to be as long as you might expect. I forget my fluid dynamics, but you can make a rough comparision between the cross-sectional area of the water over the wier and the cross-sectional area of your drain inlets. Of course, the water will not flow over the wier at as fast a rate as through the drain inlets, but you can get a rough idea as to how these cross-sectional areas compare.
FWIW, I will be using a single center overflow with a total partition length of about 36", and expect to have a turn over of about 4400 gph.
First, I would not use standpipes, even short ones, for your closed loop inlets. If the main pumps ever quit (or when you shut them down), the closed loops will continue to draw water from the overflow chamber until an equilibrium is met, which will be somewhere between the top of your sump standpipes and the top of the closed loop inlets. If you don't have enough distance (or water) between these, you may end up sucking the overflow dry.
As far as the size of the wier/partition goes, I don't think it needs to be as long as you might expect. I forget my fluid dynamics, but you can make a rough comparision between the cross-sectional area of the water over the wier and the cross-sectional area of your drain inlets. Of course, the water will not flow over the wier at as fast a rate as through the drain inlets, but you can get a rough idea as to how these cross-sectional areas compare.
FWIW, I will be using a single center overflow with a total partition length of about 36", and expect to have a turn over of about 4400 gph.
I was really considering having a central overfolw, but i was a little concerned about access with it being behid the tank. I dont want to have a huge ammount of space behind it when i set it up. Allthough this configuration would be by far the most sensible option.
Milzy, what were you saying about the closed loop equaliseation. I wouldn't have any stand pipes in the sump, only in the overflow, is that what you were saying?
Anyways, the problem you suggested, would this be overcome by littlerally having strainers attached to bulkheads in the bottom of the overflow area. Ill try to get a diagram together and send it to you. Or even better if you had schemaics of yours id love to see them.
Milzy, what were you saying about the closed loop equaliseation. I wouldn't have any stand pipes in the sump, only in the overflow, is that what you were saying?
Anyways, the problem you suggested, would this be overcome by littlerally having strainers attached to bulkheads in the bottom of the overflow area. Ill try to get a diagram together and send it to you. Or even better if you had schemaics of yours id love to see them.
Leo, beleave me the closest ive ever come to plumbing is Mario on my N64. The Overflow chambers are a common solution to sump/tank connectivity. The closed loop system we are talking about is a curculation system that runs independantly to the sump. This results in a system with no head pressure and is far more economical on pumps. And finally the durso standpipes are basically the latest solution to resolve noise problems. It stops your tank sounding like a gurgleing drain. Check out some aquarium plumbing FAQ's for a more detailed description.
As for the water dynamics, thats why i come here
As for the water dynamics, thats why i come here
This is a bit tricky to explain without pictures, but I think you have got it correct. But just to be sure, let me try explaining it again.
My overflow compartment will have 4 bulkhead drains in the bottom of the tank.
2 of these bulkheads will be connected to the sump, and will include standpipes in the overflow compartment (ie, sticking up from the bulkheads in the bottom of the tank) so that the water must rise in the overflow compartment above the top of the standpipes in order to drain into the sump. In my case, the standpipes will be about 30" high.
The other 2 bulkheads will include strainers, but no standpipes, and will be connected to the closed loop systems (I will actually have 2 separate systems, one connected to each bulkhead). Since these 2 bulkheads will not have standpipes, the water will be drawn from near the bottom of the overflow compartment.
When both systems are running (the closed loops & the sump/return system), the water level in the overflow compartment should stay above the standpipes (ie, 30" from the bottom).
The only way that the bulkheads that feed the closed loops could suck air is for the water level in the overflow compartment to drop below the standpipes that are connected to the sump. But this cannot happen because the water being drawn by the closed loops, from the bottom of the overflow chamber, is being pumped back into the tank, over the overflow partition, and back into the overflow chamber.
Nevertheless, you still do not want to use standpipes on the bulkheads that feed the closed loops because, being too close to the surface of the water in the overflow, they would suck air.
My overflow compartment will have 4 bulkhead drains in the bottom of the tank.
2 of these bulkheads will be connected to the sump, and will include standpipes in the overflow compartment (ie, sticking up from the bulkheads in the bottom of the tank) so that the water must rise in the overflow compartment above the top of the standpipes in order to drain into the sump. In my case, the standpipes will be about 30" high.
The other 2 bulkheads will include strainers, but no standpipes, and will be connected to the closed loop systems (I will actually have 2 separate systems, one connected to each bulkhead). Since these 2 bulkheads will not have standpipes, the water will be drawn from near the bottom of the overflow compartment.
When both systems are running (the closed loops & the sump/return system), the water level in the overflow compartment should stay above the standpipes (ie, 30" from the bottom).
The only way that the bulkheads that feed the closed loops could suck air is for the water level in the overflow compartment to drop below the standpipes that are connected to the sump. But this cannot happen because the water being drawn by the closed loops, from the bottom of the overflow chamber, is being pumped back into the tank, over the overflow partition, and back into the overflow chamber.
Nevertheless, you still do not want to use standpipes on the bulkheads that feed the closed loops because, being too close to the surface of the water in the overflow, they would suck air.
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