Help to ID debris in pump basket

[TopherG]

Can anyone identify what this is and where it's coming from?

Background:
I keep my floor drain line closed and the skimmer line open.
I have some dirt in pool congregated around the drain so I decided to see if it would get pulled into the drain. I slowly opened the valve. When I did, I got bubbles then a bunch of air. Then a noise and the particles in photo poured into the pump basket.
Majority of particles are gray.
The particles crumble.
Pool was refinished last summer. Aquabright applied over Diamond Brite.

(1) why there is so much air in the drain?
(2) what is the stuff in the pic and where did it come from?

 

[jblizzle]

Probably just debris from the replastering job.

How are your suction lines plumbed into the pump?
Did the air continue when the floor was running or just initially?

 

[Jamison04]

My guess is the same, debris from the refinish. Since you say you keep the drain closed my best guess is air was just trapped in the system after water was put in the pool and just never purged out until you just opened it up and flushed everything out into the basket.

 

[TopherG]

Probably just debris from the replastering job.

How are your suction lines plumbed into the pump?
Did the air continue when the floor was running or just initially?

It continued to suck air. Sometimes bubbles but sometimes big gulps.
Here's my plumbing setup.

 

[jblizzle]

Were you running 100% from the floor?

 

[TopherG]

Since you say you keep the drain closed my best guess is air was just trapped in the system after water was put in the pool and just never purged out until you just opened it up and flushed everything out into the basket.

That's a great point. With the valve closed before/since the refill, the air would be trapped until I opened it today. Thanks!

I wonder if opening the valve with the pump off would allow the water pressure to push most of the air out of the pipe...

 

[jblizzle]

It might, but I would just run the pump and turn the valve to 100% floor and see if all the air clears up after a minute or 2.

 

[TopherG]

Were you running 100% from the floor?

Never got it past 25% before closing it out of concern it might starve the pump. Maybe I was too paranoid?

- - - Updated - - -

It might, but I would just run the pump and turn the valve to 100% floor and see if all the air clears up after a minute or 2.

Okay, I'll be patient with it this time.

 

[jblizzle]

Yup, too paranoid.

The pumps are designed to prime themselves which means they may run with air in them for a few minutes.

 

[TopherG]

Thanks Jason and Jamison04! You called it! It took a few minutes but most of the air bled off. Only a little bit more debris came out so that concern is over. I still have bubbles when the floor drain is open so I guess I'll be trying to track down a suction side leak.

 

[mknauss]

It takes more suction head to pull from just the main drain. So it might just be the pump strainer lid leaking air into the system. It might be OK on skimmer, but when you switched to main drain, the increased suction caused the leak.

Switch back to skimmer and see if it goes away. When was the last time you lubed the pump strainer basket with Magic Lube?

 

[TopherG]

It went from bubbles swirling in to just a bubble stuck against the lid. Not since it was installed a year ago. I'll lube the O ring and see if that helps.

 

[jblizzle]

A single bubble sitting against the lid is often normal

 

[Jamison04]

Awesome! Yea a single bubble is often normal and I do often have one from time to time too.