Large white patches on diamond brite finish

[Underwaterflorida]

Hello. I am a new pool owner (6 months) and have some white patches all around my pool walls. Half of these white patches allowed algae to grow underneath them, making scrubbing the algae off impossible. The patches will not scrape off with a 8" wire brush but will easily scrape off with a toothbrush sized wire brush. It looks like white cement paste/plaster or maybe large calcium deposits. "Cement leaching"? I could not find a similar photo matching or describing what I have anywhere on the internet.

I can scrape all of this stuff off but I dont want to be removing cement that's bonding the quartz pebbles to the wall or further damaging the pool.

Does anyone know what they are?

I'll post a picture

 

[tim5055]

Welcome to TFP!!

It may seem strange to ask, but do you have a full set of test results??

FC
CC
pH
TA
CH
CYA

 

[Underwaterflorida]

The proper levels have not always been maintained and are still not perfect but the pool has always been clear and relatively blue for the most part. Based on a basic test kit and strips ( I think they're rubbish) the
Ph 7.2
Fc 6
Cc 6 or 7 (kit only goes to 5)
Ta. 50
Cy (added 3 lbs yesterday, strips don't read a matching color)??

I know the levels have to be tweaked but my main question is about the white patches.

 

[tim5055]

You didn't give me the one I really wanted to see, which is CH. I'm guessing you have calcium scale, but not sure.

You already admit that the test strips are rubbish, so order a TF100 and at least include the XL option. That will give you what you need while you are clearing the pool, and probably enough reagents for a couple of years normal use.

The only other real option for a test kit is a Taylor K-2006. Be careful comparing prices because the K-2006 comes in sizes, designated by a letter. The basic K-2006 has .75oz bottles. Yo need to get the K-2006-C to get the larger bottles that you want. Even then it is a little short on the reagent & powder for the FAS/DPD test.

You can buy a kit at a pool store, but again the pool store kits generally won't cut it. To effectively practice the TFPC methods, the FAS/DPD chlorine test is essential. All these kits contain that test while very few other kits do.

I also have the SpeedStir and Sample Sizer. They speed testing and accuracy.

 

[cowboycasey]

The proper levels have not always been maintained and are still not perfect but the pool has always been clear and relatively blue for the most part. Based on a basic test kit and strips ( I think they're rubbish) the
Ph 7.2
Fc 6
Cc 6 or 7 (kit only goes to 5)
Ta. 50
Cy (added 3 lbs yesterday, strips don't read a matching color)??

I know the levels have to be tweaked but my main question is about the white patches.

I know you came here for the patches, with that said, without good numbers we do not know exactly or close to what is happening... you need a good test kit and post you numbers when you get it..

We recommend the TF100, and the speedstir is so nice to have but not required TFTestkits.net or the K2006C Amazon.com : Taylor Service Complete Pool Water Test Kit K-2006C : Swimming Pool Liquid Test Kits : Patio, Lawn Garden