Pool not staying primed while draining

[Superdave]

Hey guys,

My pools is about 90% drained.... but now, it will not keep prime and finish.

Last time I did this, I had no problems.

What could be the cause?

In ground pool. 19,000 gallons. 2hp whisper flow pumps. 6 position filter control.. ( or 5 ) will double check.

Dave

 

[Superdave]

I should mention, my pool popping out is not much of a concern. My pools is mostly above ground, the deep end is about 4 feet below ground and surrounded by rock. It is a gunite pool.

I had been using waste and backwash as my filter settings.

 

[jblizzle]

I am not really surprised that the pump will not stay primed with the water that low ... you must be pulling in air somewhere.

Why do you need to drain more than 90% anyway?

 

[Superdave]

Nasty water. Actually I think the main drain line is clogged. If I fill it up, will the added water pressure help flush it out?

At this point, I am thinking I will just fill it back up. I've cleaned all plaster, so its pretty good to go.

 

[jblizzle]

You could have just SLAMed the pool and cleared the green. You will still need to SLAM to be sure.

 

[Superdave]

Need to read the site.. its been a while... SLAM?

I actually got it though. Took some 12% and mixed with water and brushed all plaster with the solution. Got about 98% of water out..

Refilling now..

 

[jblizzle]

I would still raise the FC up to SLAM level and do the OCLT to see if all the algae is gone.

SLAM is new name for the shock process ... See Pool School.

 

[Superdave]

Reading now... Put a bottle of shock in already and will put in a few more.

 

[jblizzle]

You should not be blindly adding "shock". You should be testing your current levels, using PoolMath to see what you need to add to achieve a desired result, and then adding that amount of chemicals.

 

[Superdave]

Good point..

I plan to do that after I clean my filter. Still have about a foot of water to add and spa.