Spots on the pool floor

[ddas]

Disclaimer: I don't know what material was used to make this pool. A friend told me it might be gunnite but I don't know. It is a slightly rough surface (sides and floor both).

The pool floor is blue. I've noticed over time that there are some white spots appearing on the ground, sometimes small dots, and sometimes larger patches. I *think* they are getting worse. I've taken some pics and video of them -- would anyone have any suggestions as to what they might be or if there's anything I can do about them?

When I go into the pool and touch them, they are always the same consistency as the rest of the pool floor -- in other words -- it doesn't seem like the surface is flaking/breaking off.

Video from above ground:
http://youtu.be/6bnPKnUBltE

Video underwater:
http://youtu.be/fHN6wL327z0

Photo:
[attachment=0:2v3u0k3s]pool1.jpg[/attachment:2v3u0k3s]

 

[257WbyMag]

Hard to say. Calcium deposits could account for spots such as these, but they would be somewhat raised and rough to the touch. Can you post some test results?

 

[jblizzle]

Has anyone been throwing any granular chlorine or acid into the water and letting it sit on the bottom ... possibly bleaching the surface?

 

[ddas]

(OP here.)

I just discontinued with my pool guy, after suspecting they were adding chlorine to a pool with a SWG and noticing their inattentiveness to other things. I did find large chlorine tabs added directly into the pump, which I removed (the chlorine tabs, not the pump).

I've added muriatic acid to it myself, a few times recently, in order to correct high pH and alkalinity, though I think the white spots predate that. And I'm always careful to add the acid when the pump is on, so the water is circulating and not sitting there.

I do know my water is very hard (880ppm according to Leslie's), and I have a lot of calcium deposits elsewhere (on nearby rocks, in the SWG, on the pool cover). But when I touch the white spots, they are definitely not raised (they are nothing I can pick off with my finger or with a tool). They are pretty much exactly the same consistency as the rest of the surface.

I haven't received my test kit yet; will post back in this thread once I've done that.

I really appreciate all the help from this community. Learning bit by bit here!

 

[jblizzle]

Just so you know. There is nothing wrong with adding extra chlorine to a SWG pool ... in fact it is a very good idea to do so before and/or after an heavy use to ensure adequate FC is maintained.

 

[ddas]

Thanks for that tip -- learning. I had been told by others that a chlorine tab inside the pump was a strict no-no (could damage the pump). And I assume it's better to add salt and let the SWG do its work, unless there's a compelling reason to add chlorine (like you say -- if I'm anticipating heavy use).

I'll know more about FC once I get the test kit.

 

[jblizzle]

Certainly putting a puck in the skimmer or pump is NOT what I meant. But, adding some bleach/liquid chlorine to the water is the usual method to add a temporary boost in FC levels.

Adding more salt when not increase the FC level (if that is what you meant?).