White powdery substance on bottom after opening

[njswimguy]

Hello. This is my 3rd opening after having the pool completely remodeled and switching to a SWG.
The 1st year the pool company did all my chemicals (renovation ran into the late fall so pool was only open for about 3 weeks before closing) - with all their pool store goop - and when we opened there was a ton of what looked like "white powder" at the bottom. Almost like the salt looks when you add it to water.. The pool guy said "yeah, all our salt pools have that each year". I vacuumed to waste and never saw it again. (By "ton" - I mean a good 2 inches deep in a few spots!)

Then in year 2 (after following the regimen on this website, and no pool store junk), when we opened there was very little of that white powder, (mostly in the deep end) but still there.

Now we are in year 3, and there is even less of this white powder (only about 10-12 small piles/spots), but I'm vacuuming to waste today to get rid of it.

Any ideas what this could be? Maybe calcium falling out of the water? Otherwise the water is clear, minus worms and spiders.
I'm more curious than anything and wondering if other have seen this. I just find it odd that the pool company seems to think it is normal but doesn't know what it is! ?!
Thanks all
PS i only see this at opening. No other time of the season.
PPS: I'm to the point where I have them open the pool but they aren't allowed to add any chemicals, and i don't take my water there for testing or advice anymore.

 

[mknauss]

Can you capture a sample of the material?

 

[ajw22]

See this discussion about calcium scale or calcium crystals in another NJ pool...

I think I have Calcium Crystals not scale after opening new pool

Hi, so we just opened my pool and looking down at my pool from a slight angle it looks like air bubbles on the pool wall. When I get closer and feel it they are clear sea salt like granular pieces. Feels like it too. I know it’s not salt but it was the best way to describe the look/ size and...

www.troublefreepool.com

 

[njswimguy]

Thanks. I'll try to get a sample.
It isn't like the crystals in that other post. This powder is so fine it blows right through the glass sand filter. (one of the reasons I need to vacuum to waste) it also isn't stuck to any surfaces. Just lays there... like you dumped a salt bag in and didn't brush...

 

[mknauss]

What chemicals are used in the pool? Dry acid or muriatic acid?

 

[YippeeSkippy]

I'm wondering if its calcium coming off your SWG plates?

Maddie

 

[jark87]

I thought I had a DE leak from my filter a year or so ago. Turns out that wasn’t the case, but to try and determine where “dust” particles were coming from, I hung dark dress socks from the the pool returns using rubber bands to see if the substance was flowing into the pool from the pump. Might be worth a try to isolate the origin.

 

[njswimguy]

Muriatic acid is used.
Regarding the SWG plates - this stuff builds up over the winter with the cover on and plumbing winterized. It is there before the plugs come out of the lines... Almost like it falls out of the water over the winter. (Solid safety cover, btw)...

I unfortunately can't capture a sample since there is so little this year and it is in the bottom of the deep end. (and the water is too cold to enter). Maybe this mystery will just go on. At this rate, I'm wondering if next year I may have none of it, since it decreases in volume each year since I've prevented the pool company from doing their thing. I appreciate the thoughts.

 

[mknauss]

Muriatic acid is used.

Great.
It sounds like some kind of scale type substance. If it is not sticking to the surfaces, I would not worry about it.