Issue with my pump

[Linguisa]

Twice is the last week or so I've come home from work to find the water in my tank is touching the glass cover. Water is still flowing down into the sump but it's at a much slower rate than the pump is pumping into the tank. I unplug the pump wait for the water level to reduce in the tank, and then plug the pump back in and all appears to be back to normal - for a while.

 

I suspect that there might be some build up in the hose carying water down to the sump, although I can't imagine what it could be. I'm worried that the next time the water will over flow right over the top of the tank! Is this a common problem? Could my pump be broken - and randomly pumping faster?

[Jon Lazar]

Linguisa,

 

It's unlikely something is wrong with your pump to make it pump faster than it's supposed to.

 

It's somewhat likely that something is restricting your drain, making your water level higher...perhaps a snail shell or other bit of hard debris somewhere in your plumbing. IME the most likely cause is a buildup of algae in the teeth of your overflow, making the water level rise. (Note that this may also cause your salinity to decrease if you have an ATO.)

 

Jon

[flowerseller]

Is the tank drilled for a drain to the sump or do you have an external overflow box?

If the later, you could be developinging an air pocket in the siphon tube.

What size pump and how much head?

[Origami]

Similarly, if your drain is unvented and/or has a high spot along the way, it's possible also that a bubble is getting trapped and impeding flow. It doesn't have to be a hard obstruction holding things up. Where are you located?

[Integral9]

Could also be algae build up in the U-pipe, if yours is like mine and clear. I use a baby bottle scrubber on a flexible handle to clean it out.

[Boret]

If you have an overflow box a good idea is to put a sheet of aluminum foil on top to prevent light to get into the box and tube and reduce the growth of algae.