White Residue above Water Line

[woody]

I have a white residue above the water line all around the pool. It looks like calcium deposit, but does not react to acid. It does seem to clean off with just water, but reappears a day or so later. Could it be salt from evaporation? If so, is this a problem?

Here are my numbers:
FC 3.4
CC 0.0
pH 7.7
TA 80
CH 300
CYA 45
Temp 86°F
Air Day 72°F
Air Night 45°

The pool is currently heated, but I will probably cut back on that soon.

 

[JasonLion]

Yes, that sounds just like salt. It is generally harmless as long as you wash it off every couple of weeks. Do you know your salt level? You don't usually get obvious salt deposits unless the salt level is high, though there are many other things that can affect it.

 

[woody]

My SWG indicates 3350-3750 ppm. I have a hard time reading the test strips, but it looks like a 5.8 reading which corresponds to 3470 ppm. Anyway, doesn't seem like a lot of salt to me.

Is there any way to test the residue?

Is there a better way to clean it off other than just brushing with pool water?

 

[duraleigh]

Is there any way to test the residue?

Taste it.

 

[woody]

Yea, I thought about that, but was afraid my tongue would stick to the side of the pool!

 

[duraleigh]

Yea, I thought about that, but was afraid my tongue would stick to the side of the pool!

If you're serious, simply wet the end of your finger and touch it to the residue, then taste the end of your finger.

 

[Poolsean]

Yea, I thought about that, but was afraid my tongue would stick to the side of the pool!

LMAO!!!

I had visions of my favoritiest Christmas movie of all times!!! A Christmas Story.

Salt dissolves easily when wetted. If you're having a problem with the water splashing on your tile because your pool has alot of aggitation (waterfalls, spray nozzles, windy conditions), there may be a tendency for the salted water to splash on the tile and when the water evaporates, it can leave a residual salt.
What is probably causing the reoccuring issue is that you're using the pool water to clean it. If you use fresh water from your garden hose, this will wash the salt residual off the wall and should probably prevent this situation.

 

[woody]

Thanks Sean. That sounds logical. The area that is see it most often is near my spa spill over which is always on when the pump is running. I'll try the water hose.

(Christmas story is what I was thinking of also !)