Return Pump Malfunction

[Hannah Veldhuizen]

Hello all,

The person at my college who has been taking care of a 250 gallon reef tank with a 30 gallon sump has quit this job spontaneously. This has forced me to jump into this position although I know very little information about the equipment of the tank. Today the return pump has slowed or possibly stopped its output.

Here are the prior events that have occurred to this failure:

On Monday, the auto top off bucket cracked and drained and caused the auto top off to cease operation. By Tuesday, a large amount of water had evaporated from the tank and there was no auto top off to replace this water. When I came in on Tuesday the return pump to the main return line and a return pump to the algae turf scrubber had dried up and no water was flowing from the sump to the main tank. (The main return line is submerged 2 inches under the water line, but there are holes in the sides to prevent back siphoning).

On Tuesday, I replaced the auto top off bucket and I filled the tank back up with RO water to what I thought was the correct height and when I turned the pumps back on everything worked fine. However, when I came back on Wednesday and I pushed the feed hold button (this turns off both return pumps for 15 minutes), the sump overflowed. I believe I added too much water on Tuesday, so I drained some of the water from the sump and slowly added RO water until the water line in the main tank was high enough to reach the overflow pipe.

Now, the tank and sump is level and the sump no longer overflows when the power shuts off. But, the main return pump is not moving the amount of water it should. Could this be caused by air entering the pump when it was dry or a debris obstruction?

Attached pictures are:
1. An algae turf scrubber similar to mine
2. The main return pump (Blue Line Aqua Pump)
3. An overflow box/pipe similar to mine

Thank you!

 

[Palyzoa]

If the pump ran dry it could have cause some damage or most of the time it will seize up and not work at all. You could try buying a replacement pump to see if that helps with flow. Are there any gate valves or ball valves to control the flow? Maybe one got bumped and is restricting flow more than usual.

 

[Palyzoa]

Oh yeah and Welcome to R2R!

 

[Hannah Veldhuizen]

If the pump ran dry it could have cause some damage or most of the time it will seize up and not work at all. You could try buying a replacement pump to see if that helps with flow. Are there any gate valves or ball valves to control the flow? Maybe one got bumped and is restricting flow more than usual.

Yes, there are gate valves. I will make sure those are completely open tomorrow. I forgot to mention that the main return pump is a Blue Line Aqua external pump. Do external pumps fail like submersible pumps when they run dry?

Thank you.

 

[Palyzoa]

Yes, there are gate valves. I will make sure those are completely open tomorrow. I forgot to mention that the main return pump is a Blue Line Aqua external pump. Do external pumps fail like submersible pumps when they run dry?

Thank you.

I don't have much experience with external pumps but I would imagine it would be the same deal.

 

[laverda]

Yes, there are gate valves. I will make sure those are completely open tomorrow. I forgot to mention that the main return pump is a Blue Line Aqua external pump. Do external pumps fail like submersible pumps when they run dry?

Thank you.

It really depends on the design of the pump. Generally an external pump will tolerate running dry better then an internal pump. Some external pumps rely on the water for cooling, so they are more likely to have a problem wher run dry. If it is not working properly, take the actual pump part apart and inspect it. You may find an issue that can be fixed. If you don’t find anything there make sure the motor is turning freely. If not the bearings on most external pumps can be replaced easily and cheaply.

 

[racin2438]

If possible, can you pull pump out and inspect it, also checking for blockage, ??? check for scoring- hot spots
if not already done... put a mark on sump when flow is running get level marked then turn off pump and get the level on sump marked, take a look at it just before you turn off...if level is high on bottom mark ..it will make your top mark high and maybe overflow. have back up s handy or make plans for them soon.

 

[Brew12]

Yes, there are gate valves. I will make sure those are completely open tomorrow. I forgot to mention that the main return pump is a Blue Line Aqua external pump. Do external pumps fail like submersible pumps when they run dry?

Thank you.

Only fully open the valves on the return, not the drains! Hopefully they are dialed in for you and you don't want to mess with those settings.

I am not familiar with these pumps but I do agree that most pumps fail catastrophically. I've never seen an aquarium pump with a soft impeller but if these have them, they can easily be damaged when run dry. Can you estimate how much flow is reduced?