Advise on pool store vs K2006 test results

[etreaster]

I noticed white streaking in my pool near the end of last year (was just installed last year) and pool store wasn't very helpful to find out what it was. This year I noticed the steps, the shallow end and down the slope was rough. The sides and deep end (6ft) are smooth. I was anal about brushing the pool last year to make it smooth and now it's not. You can see white streaking throughout especially coming from the 2 floor jet returns.

I mentioned it to the store owner this year and without looking he said it was scale. He looked back at previous sample tests and said my TH was from 180-360. IMO this is not that high. The pool was filled by a company. As I am reading here, high pH can cause scale...my cheapo test kit they gave me last year was always on the high end...but when I took it to them to test, it was always in range but TA was either high or low. I recently bought the K2006 and compared samples...pH(Store) was 7.5, (mine) about 7.9ish, TA from store was low (I don't recall number) b/c they wanted me to add Alk Increaser, mine was high (<200).

So, it's difficult to trust one over the other b/c of the large discrepancy in results but since I have what seems to be scale, I am going with my test results.

So, my questions are:
1. How do I know for sure it is scale and if not what else could it be? I think that my pH was on the high end all year last year and contributed to the scale even though my TH was not that high. Is this correct assumption?

2. Can scale truly be resolved without draining and acid washing. The pool store gave me some chemicals to add ( I don't recall name, clear jug w/ purple label) and a wire/plastic pool brush.

3. I have been trying to get my pH on the low end. I went from 7.9/8.0 to 7.2+/- using dry acid. TA was >200. Yesterday pH was back up to 7.8 and TA 180. I added more dry acid. Will decreasing pH help 'break up' scale.

Any thoughts/help would be greatly appreciated. I am irritated b/c I hate rough bottom concrete pools and I prided myself in having a smooth finish and now I have half rough/half smooth pool

Thanks
Eric

 

[JohnT]

Welcome to TFP!

You certainly want to keep your pH on the low end. Your high TA is contributing to both your CSI and your trouble keeping the pH down. If you follow the Pool School article on Lowering Total Alkalinity , you will reduce the tendency of scale to form and make your pH more stable.

The wide range of readings the pool store gave for your hardness makes me doubt their testing ability. What do you measure for CH with the K2006?

There is also a Pool School article on Calcium Scaling

 

[etreaster]

Today's readings:

pH: 7.6
TA: 175
FC: 3.5
CH: 340
CC: 0

I added more dry acid (~3 pnds) to get down to 7.2. Once I get pH and TA down, will I be able to get rid of the scale build up I already have?

Thanks

 

[JasonLion]

Removing scale without draining the pool is a long slow process that doesn't always work out very well, though it can work some of the time. You have to bring the TA way down before there is any chance of some of the scale going away. Continue to follow the lowering TA process as described in Pool School.