Can someone tell me what these spots are?

[Benchi1010]

Hello, been using the tfp method (liquid chlorine,muriatic acid from home depot) for about a year and all has gone well. I recently been noticing some spots as seen in pics (Line seen in pics is a internet cable above pool). Any idea what these can be? How can i remove? I moved into this house about two years ago and previous owner used leslies pool supply for water testing and also used leslies powder plus for shocking. I have a pentair fns plus 48 filter and right now I am topping pool off about once every week in this summer(los angeles -south bay). I add muriatic acid as suggested in tfp calculator because my ph rises to about 8. I will post water parameters below using a taylor k2006 kit. I use a dolphin s200 for vacuuming about once a week. Please let me know any details i am missing, or any equipment you guys recommend? Thanks in advance


20k gallon pool
FC-6
ph-7.6
ta-85
ch-550
cya-50

 

[Texas Splash]

Welcome to TFP! Do you have any trees nearby? Any chance those are from tree dropping? Or has there been any landscaping work done lately?

How old is this pool? That looks like a long hairline plaster crack as well correct?

Pool Care Basics

 

[Mdragger88]

U can try some of these methods to determine what they might be & if they are possibly from the things that Tex mentioned

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

 

[Benchi1010]

Welcome to TFP! Do you have any trees nearby? Any chance those are from tree dropping? Or has there been any landscaping work done lately?

How old is this pool? That looks like a long hairline plaster crack as well correct?

Pool Care Basics

Thanks for response, pool is about 6 years old. What looks like a hairline crack is actually a internet cable running above pool. Really no landscaping done lately and last time i went for swim the spots had a rough surface over them, some kinda build up. I will trow a puck above and do some scrubbing later tonight and see if that helps.

 

[Texas Splash]

the spots had a rough surface over them, some kinda build up.

Wonder if they might be calcium nodules.