Help Me Identify This White Hard Substance

[diamonddog]

Pool has about 740 ppm TDS. I thought it was mineral precipitation, but there are no "flakes" floating around throughout my pool

PH is at about 7.5, TA is 80, Free Chlorine 3ppm. I have a Ecomatic SWG that they say runs better at higher salt levels (min 3000), and mine is at around 3700 ppm. Pool is about 4 years old and there is very little scaling on the pool tile. There is a faint amount and even muriatic acid wont take it off. Only telling this as I don't think this is typical mineral scale.

This bright white (like stryofoam) substance is forming on the saltwater generator grids and ends up on the pool floor by the jets. I theorize it is breaking free and exiting through the jets. Not a ton of it, but maybe 4-5 pieces of this (see picture) are under the jets resting on the pool floor.

Its hard, and thick (not like typical mineral scale). Somewhat porus. About the same hardness as a graham cracker and if you smash it around, it will turn into fine grains. If I keep smashing it in my fingers it will turn into a paste like consistency. I tasted it (just touched my tongue on it) and it was barely salty

 

[duraleigh]

put a drop of muriatic acid on it. If it fizzes, it is calcium scale......that's my bet.

 

[Swampwoman]

^And let me know if it doesn't fizz...I have other tests you can do by grinding it up with mortal and pestle. The conditions inside a salt cell can cause just about any combo of carbonate scale, and IME, some don't fizz

Do you use dry acid at all? Or just MA? If the sample doesn't fizz, post a complete set of water test results.

 

[diamonddog]

Yes, Acid will make it fizz.

But why would it be forming predominantly on the salt cell and not other places in the pool?

I thought scale was a lot "harder" in texture (like the scale on my pool tile which you can not mash up with your fingers"

Is there a way to address this on the salt cell besides just cleaning it with an acid solution? Trying to determine the actual cause

 

[pooldv]

PH is higher in the cell so scale forms more readily. There are different types of scale with different mineral make up. Maintain your CSI around -0.3 and see how it does. More here, Pool School - Calcium Scaling

Add your pool info to your sig so that we can better help you. More here about what to put in your sig and how to do it, Pool School - Read This BEFORE You Post

 

[diamonddog]

I added all my info in the signature.

Calcium Hardness was just tested at Leslies (sometimes I question their accuracy) and it is 600 ppm. They said my TDS is over 5000 ppm but salt is throwing that off. CA is at 50 (it was at 80 about a month ago so I question the accuracy of this as well)

 

[diamonddog]

^And let me know if it doesn't fizz...I have other tests you can do by grinding it up with mortal and pestle. The conditions inside a salt cell can cause just about any combo of carbonate scale, and IME, some don't fizz

Do you use dry acid at all? Or just MA? If the sample doesn't fizz, post a complete set of water test results.

I use only liquid MA.

Free Chlorine is 5
Salt is 4500
Calcium Hardness 600
TA 70
ph 7.6

 

[PAGirl]

Do you still have the Taylor test kit listed in your signature? If so, which version is it?

 

[pooldv]

We always question test results from the pool store. Do you have any test results?

 

[diamonddog]

Do you still have the Taylor test kit listed in your signature? If so, which version is it?

yes. It the Leslie branded one 18-571 is the number on there. I have an electronic Hatch salt meter that I calibrated in a 3000 ppm baseline solution. I do not have a CYA test nor do I have a hardness test. I have electronic TDS meters made by HM