Durso and gate valve

[careefer]

I recently replumbed my sump so the drains have gate valves on them and replaced the original drain arrangement with Dursos (which is kind of what it came with but the originals were odd pipe sizes and hard to fix or adjust due to previous owner gluing the adjustable sections) . The tank is an Aqueon 120 and has the dual overflows with 3/4" returns and 1" drains in each overflow compartment. I thought the gate valves would allow me to quiet the overflows and indeed I had it pretty well tuned and much quieter than previously. BUT the system seems very touchy and a very minimal change to the gate valve can cause the tank to start thinking about overflowing or else bring the water level in the overflow so low that it starts to suck in lots of air and get noisy which is the situation I had before all the changes

Thinking about the fluid flow it seems that if the return and drain combination is just off by 1 gallon per hour then you will either slowly get a low level in overflow compartment or a big puddle of water around your tank and a really PO'd wife. I doubt the flow from the dc return pump is stable at the 1gph level nor the drains for that matter with occasional bits of debris getting sucked down there.

One solution would be an emergency drain but I don't really see how that is an option the way the tank is set up and I am not drilling a live 120 gallon tank! Is this just the way these things are with overflows of this type, in need of fairly constant attention or do I just not have it set up right? Is it better to not rely on the gate valves and just tinker with the size of the air holes on the returns to get things kind of balanced but with the overflows maybe running a little noisy but with less risk of overflow? Do I put a float valve in the overflow chamber so that in an emergency situation the dc return shuts off to prevent a disaster? What do other people do?

 

[Brew12]

I recently replumbed my sump so the drains have gate valves on them and replaced the original drain arrangement with Dursos (which is kind of what it came with but the originals were odd pipe sizes and hard to fix or adjust due to previous owner gluing the adjustable sections) . The tank is an Aqueon 120 and has the dual overflows with 3/4" returns and 1" drains in each overflow compartment. I thought the gate valves would allow me to quiet the overflows and indeed I had it pretty well tuned and much quieter than previously. BUT the system seems very touchy and a very minimal change to the gate valve can cause the tank to start thinking about overflowing or else bring the water level in the overflow so low that it starts to suck in lots of air and get noisy which is the situation I had before all the changes

Thinking about the fluid flow it seems that if the return and drain combination is just off by 1 gallon per hour then you will either slowly get a low level in overflow compartment or a big puddle of water around your tank and a really PO'd wife. I doubt the flow from the dc return pump is stable at the 1gph level nor the drains for that matter with occasional bits of debris getting sucked down there.

One solution would be an emergency drain but I don't really see how that is an option the way the tank is set up and I am not drilling a live 120 gallon tank! Is this just the way these things are with overflows of this type, in need of fairly constant attention or do I just not have it set up right? Is it better to not rely on the gate valves and just tinker with the size of the air holes on the returns to get things kind of balanced but with the overflows maybe running a little noisy but with less risk of overflow? Do I put a float valve in the overflow chamber so that in an emergency situation the dc return shuts off to prevent a disaster? What do other people do?

It sounds like you may not have it set up right.

Are you trying to run them as a full siphon drain or are you letting them suck air in?

 

[careefer]

It sounds like you may not have it set up right.

Are you trying to run them as a full siphon drain or are you letting them suck air in?

They have air holes in the caps so i do not believe they should be full siphon. Maybe those holes are too small?

 

[Brew12]

They have air holes in the caps so i do not believe they should be full siphon. Maybe those holes are too small?

Its possible. Durso's should be fairly forgiving to small changes in flow.

What size durso's are you running and what do you estimate your total flow to be?

 

[careefer]

I have two 1" durso drains. I am running a Varios6 at max flow and I am guessing my flow is around 1100 GPH after head losses.

 

[Brew12]

I have two 1" durso drains. I am running a Varios6 at max flow and I am guessing my flow is around 1100 GPH after head losses.

That is likely your problem. You are hitting very close to the theoretical max flow rate of 1200gph.

 

[careefer]

Isn't a 1" schedule 40 pipe good for about 960gph gravity fed? so 1920gph for two of them? I mean if I leave both gate valves wide open then the drains have no problem keeping up with the flow but that leads to a big difference in level between the tank and the overflow compartment and a lot of noise and increased air getting sucked into the pipes which creates more noise in the sump.

 

[Brew12]

Isn't a 1" schedule 40 pipe good for about 960gph gravity fed? so 1920gph for two of them? I mean if I leave both gate valves wide open then the drains have no problem keeping up with the flow but that leads to a big difference in level between the tank and the overflow compartment and a lot of noise and increased air getting sucked into the pipes which creates more noise in the sump.

A 1" schedule 40 pipe is good for around 960gph when running at a full siphon. You need to have a good amount of air being sucked into the system as part of how a durso works.

The trick is finding a balance between water flow, air flow and noise to make it work.

 

[careefer]

A 1" schedule 40 pipe is good for around 960gph when running at a full siphon. You need to have a good amount of air being sucked into the system as part of how a durso works.

The trick is finding a balance between water flow, air flow and noise to make it work.

I see, so basically the closer you try to get to completely silent, the more you are playing with the possibility of having the tank overflowing if there are slight changes in flow? That makes sense. Since the Varios comes with a float valve to shut it off I think it makes sense to use that in one of the overflow chambers to prevent any disasters. Thanks for the help!

 

[Brew12]

I see, so basically the closer you try to get to completely silent, the more you are playing with the possibility of having the tank overflowing if there are slight changes in flow? That makes sense. Since the Varios comes with a float valve to shut it off I think it makes sense to use that in one of the overflow chambers to prevent any disasters. Thanks for the help!

You can get durso's dialed in to be fairly quiet. When I ran my 2 durso system I drilled small extra holes to get the right airflow. If I needed to cut back on it, I sealed them with 2 part reef putty. To do it again, I would have installed air valves similar to these on the air lines.
https://www.bulkreefsupply.com/micro-airline-control-ball-valves-6-two-little-fishies.html

The other thing about all drains but especially with Durso's is that they will quiet down over time. Once some nice slime starts growing on the pipe the water will flow more smoothly resulting in a quieter system.

 

[nereefpat]

Nothing good can come of you putting gate valves on durso standpipes.

If you want to run a quiet drain that uses gate valves and syphons, then you need emergency drains.

What many folks do in your situation is convert your durso stockpipe system into a Herbie. Each overflow will have a siphon and an emergency, using the smaller pipe for the syphon and the larger one as the emergency. Then run a return or two over the back of the tank.