Return pump section in sump

[Total Newb]

Hey friends. Total newb and never operated a sump before. Have everything up and running. My Varios return pump is set at the minimum setting. When I go to increase the flow it empties the return tank too fast and ends up sucking air. What I am doing wrong?? I have the flow valve adjusted all the way to the left. Reefer 750.

 

[Little c big D]

Are you able to open the gate valve on the overflow to allow more flow? It sounds like your drain is not keeping up with you return speed

 

[shakacuz]

the return pump is pumping water faster back up to your display faster than the water is reaching the return chamber. either lower the return pump speed more, or increase the drain from your display via gate valve

 

[Uncle99]

Any restrictions in the flow in the sump like sponges for example?

 

[dbowman5]

the third idea that needs to be addressed is the volume of water in the return chamber. when you start the pump there needs to be enough volume to fill the pipes and still have enough to keep the intake of the return pump submerged far enough to avoid sucking air.

 

[Little c big D]

the third idea that needs to be addressed is the volume of water in the return chamber. when you start the pump there needs to be enough volume to fill the pipes and still have enough to keep the intake of the return pump submerged far enough to avoid sucking air.

I can only imagine if it's full at low speed then volume wouldn't be issue?

 

[KStatefan]

I can only imagine if it's full at low speed then volume wouldn't be issue?

When you increase the flow to the display the water level in the display will go up. The amount will depend on the overflow design. Without adding water it is possible for the return pump section to be to low.

 

[Little c big D]

When you increase the flow to the display the water level in the display will go up. The amount will depend on the overflow design. Without adding water it is possible for the return pump section to be to low.

The water shouldn't increase if the flow is increased in the drain

 

[KStatefan]

The water shouldn't increase if the flow is increased in the drain

It will. The flow thru the weir can not remain at the same height and increase in volume

 

[Little c big D]

It will. The flow thru the weir can not remain at the same height and increase in volume

The weir can handle much more flow than the drain. I went from a 337gph pump to a 790gph pump with 0 change in water level. If water level rises then the drain isn't allowing enough through.

 

[KStatefan]

The weir can handle much more flow than the drain. I went from a 337gph pump to a 790gph pump with 0 change in water level. If water level rises then the drain isn't allowing enough through.

The weir can not flow more volume in the same area. There is only one way to increase area and that is by the water level going up.

 

[Little c big D]

The weir can not flow more volume in the same area. There is only one way to increase area and that is by the water level going up.

The weir can handle x amount of flow. Once you exceed flow the tank will either over flow or drain the pump chamber. If you don't exceed the max flow rate then the water doesn't rise. This is a reefer system so if the pump doesn't exceed the max flow of the drain then the water cannot rise in the tank. The weirs have to beable to tolerate the max flow of both the drains and emergency drains combined. Otherwise the tank could potentially pour over out of the tank. Which means it's likley the pump is over powered or the gate valve on the drain is not open enough

 

[KStatefan]

The weir can handle x amount of flow. Once you exceed flow the tank will either over flow or drain the pump chamber. If you don't exceed the max flow rate then the water doesn't rise. This is a reefer system so if the pump doesn't exceed the max flow of the drain then the water cannot rise in the tank. The weirs have to beable to tolerate the max flow of both the drains and emergency drains combined. Otherwise the tank could potentially pour over out of the tank. Which means it's likley the pump is over powered or the gate valve on the drain is not open enough

It will not be at the same height at all flow amounts. The larger the weir the lees it effect it will have on it but it will change with flow changes.

In this picture the blue line is where the water level will be a minimum flow and the red line is where the water level will be a the maximum of the weir. all other flow will be some where in between the two lines.

 

[nereefpat]

I agree that water level in the display tank will change based on flow from the return pump.

OP, I would add more water so that the pump isn't sucking air. Then do a 'power outage' test to make sure when the pump is shut off the sump can handle the extra volume.

Edit: What type of drain system are you using?

 

[Little c big D]

I agree that water level in the display tank will change based on flow from the return pump.

OP, I would add more water so that the pump isn't sucking air. Then do a 'power outage' test to make sure when the pump is shut off the sump can handle the extra volume.

Edit: What type of drain system are you using?

This is why I gave the info I did. Unless you exceed the max capacity. Tank water level stays almost exactly the same. A mm change maybe? Op says in main post this is a reefer 750. The reefer is recommended for 1850gph return. Advising them to add water before simply checking a gate valve could cause issues.

 

[Total Newb]

Thanks for all the responses. I am using the Red Sea sump with Varios pump. And there is a spongy filter think in the sump compartment directly before it water just the return.

 

[Little c big D]

Thanks for all the responses. I am using the Red Sea sump with Varios pump. And there is a spongy filter think in the sump compartment directly before it water just the return.

On the pipes coming down from the tank into the filter sock area, one should have a gate valve on it. A wheel correct?

 

[Little c big D]

 

[Total Newb]

Right on!! I have that turned all the way to the left which I believe is fully open.

 

[Little c big D]

Right on!! I have that turned all the way to the left which I believe is fully open.

And which varios are you using? The 8? And was it all the way open when it drained the return?