Major white stuff - scale? Hard water?

susanbogd

Member
May 3, 2019
5
Boise
20191027_185535.jpg

We have a small lap pool indoors. We keep a cover on it because we have issues with humidity. We have a dehumidifier inside the pool room. Our water is a community well and is super high in alkaline and very hard. We have a water softener for the water inside the house but not for the pool. We noticed a bunch of scale that we have to vacuum out. Today I was testing the pool and I noticed that the top of the cover has a huge growth of white stuff that looks like hard water or scale or salts or I don't know what? Does anyone have any suggestions on what it could be and how to get rid of it? Thank you so much you guys are awesome
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Hello Susan and welcome to TFP! :wave: Before we hop on the scale (bwaahaaaaa), can you provide a full set of water test results with a TF-100 or Taylor K-2006C test kit? We typically like to see them as follows:
FC
CC
CYA
PH
TA
CH
Water temp would be good as well

Have you ever tried to collect that white stuff and test it with some white vinegar or muriatic acid (watch for fizzling)? Also let us know how you chlorinate and don't forget to update your signature with all of your pool info and equipment. Scale may be an issue if the water is over-saturated with calcium or of other parameters contributes to calcium precipitating outwards to something, but we'll need that info.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
HAHAHAHAHA....are you a dad?
Why yes I am, and a very sarcastic one with the kids at that. Ha. As for your numbers, not bad. A couple things:
1 - Indoor pools don't need much CYA (stabilizer) since there are no worries from sun oxidation. However you should have about 20-30 ppm of CYA. Water with no CYA allows the free chlorine to be much more harsh. So I would recommend using the PoolMath tool or APP to increase CYA to at least 20. Then keep the FC and CYA balanced as noted on the FC/CYA Chart.

2 - As for the other test parameters and possibility of scale, I have a feeling it may not be scale if it didn't fizz on you. In addition, I plugged those four numbers (PH, TA, CH, and water temp) into the PoolMath tool and your "CSI" number shows as balanced. I'm starting to wonder if that's some other chemical reaction. I see you have a salt cell, so we can rule-out odd chlorine products. Have any other chemicals been added recently?

@JamesW or @JoyfulNoise did I miss any other areas of concern?
 

susanbogd

Member
May 3, 2019
5
Boise
Hello again!

I will work on the CYA. I did purchase the PoolMath app and I love it btw.

There have been no other chemicals added. Even though the calcium is correct, we have serious hardwater issues and had to add a water softener to our in house water to prevent all the white buildup on our faucets/sinks/countertops. Could it be something like that?
Any other ideas?
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
32,859
Sebring, Florida
"Hard water" is almost always calcium. White solids precipitating from pool water is almost always calcium as well
We noticed a bunch of scale that we have to vacuum out. Today I was testing the pool and I noticed that the top of the cover has a huge growth of white stuff
Are you saying you can vacuum this stuff off the pool floor and it is also accumulating on the underside of the pool cover? So, if the muriatic doesn't make it fizz, then it is NOT calcium but I have no clue what it can be

Can you recover some of it from the vacuum (or scoop it up) and let it dry out and then take a pic?
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
489
Spring Valley, NY
HAHAHAHAHA....are you a dad? Because that was a killer dad joke :)

Here are my numbers:
FC-3
CC-0
CYA-0 ??? i did the test, it's an indoor pool, and there was zero cloudiness here
PH-7.4
TA-150
CH-300
Water Temp - 82 and rising - we just turned on the heater
Attach files
=195608&hash=0cd2a9c1eafc655f9e5b2d8d68187939']=195608&hash=0cd2a9c1eafc655f9e5b2d8d68187939']=195608&hash=0cd2a9c1eafc655f9e5b2d8d68187939']

I did collect the white stuff and added muriatic but there was no fizzing.
Thanks so much!
You would benefit from a UV system as you don't have direct sunlight. A pool needs some UV to keep the CC in check as yours is but it my not stay that way.
I wonder if the flaking is some kind of scaling from the plaster. Possibly a rework going bad.
 

susanbogd

Member
May 3, 2019
5
Boise
maybe it's salt!! We vacuumed a bunch of white stuff off the bottom a few weeks ago, like piles of it. I just assumed it was the same but maybe There's two different kinds of white stuff? How do i know if it's salt? Should I sprinkle some on my eggs? Jk.

I'll take a pic and post soon and also see if it dissolves in water
 
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JamesW

TFP Expert
Mar 2, 2011
16,589
It might be salt. Get a liter of distilled water and add about 3 grams of the substance to the water. Stir to dissolve.

If it's salt, it should dissolve quickly and the water should test at about 3,000 ppm for salt using a K-1766 salt test kit.

If the test is negative for salt, test the sample for calcium.

If it doesn't fizz with acid, it's not calcium carbonate, but it could be calcium sulfate or calcium phosphate.
 
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susanbogd

Member
May 3, 2019
5
Boise
So the substance did dissolve. I think it's salt.

So the other major white stuff IN the pool, could this be scale from high TA or PH? I've been working on getting it lowered. Adding more acid and aerating per PoolMath. Is there any way to get rid of the existing white stuff (scale?).

Thanks so much everyone for being so helpful. We love our pool so much and try to swim a mile every week.