Questions about my pool finish

FloridaPoolGal · May 10, 2016

When we purchased the house, the seller said the pool had recently been refinished. The house was a foreclosure and was vacant for at least a year prior to being rehabbed. Our only experience has been with a vinyl liner pool (2001-2004) so I don't know what to expect with a concrete pool. We've been in the house a year now and the finish looks splotchy and old.

What type of finish is it? Does there appear to be anything wrong with it other than the splotchiness? I can't really tell if it always looked like this because it was impossible to take baseline pictures until I recently got a GoPro. We keep looking at the finish and saying to ourselves, "Did that streak used to be there?" It seems like there are more black specks in the finish than was there originally but I have no way of knowing for sure. Before TFP, I was using the chlorine tabs from Clorox and I was pretty good about keeping my pH in the mid to high 7's and my TA about 100-110. Our CH is always around 250-300.

I think I caused some color change near the main drain from powdered shock (back in my pre-TFP days). I don't really care if it is splotchy. I just want to make sure it is sound.

The bottom of my pool looks dirty in these pictures but it's not! It got a good brushing this morning and the water is nice and clear.

pooldv · May 10, 2016

It is some type of pebble finish. The finish looks sound. There is a fair chance that it is scale. Is the surface rough?

To prevent further scale manage your CSI using Poolmath. Enter all your test results and it will calculate a CSI number. Keep thwt number between -0.1 and -0.3. Adjust PH and TA to tweak the number.

More here, Pool School - Calcium Scaling
And here, Langelier and Calcite Saturation Indices (LSI and CSI)

FloridaPoolGal · May 10, 2016

pooldv said:
It is some type of pebble finish. The finish looks sound. There is a fair chance that it is scale. Is the surface rough?

To prevent further scale manage your CSI using Poolmath. Enter all your test results and it will calculate a CSI number. Keep thwt number between -0.1 and -0.3. Adjust PH and TA to tweak the number.

More here, Pool School - Calcium Scaling
And here, Langelier and Calcite Saturation Indices (LSI and CSI)

Yes, it is a moderately rough surface (smoothly rough, if that makes any sense). It looks like I really need to stay on top of the pH to stay in the -0.1 to -0.3 range. That seems to be the input that really moves the CSI number. My pool loves to be up at 8.

FloridaPoolGal · May 11, 2016

Once the water gets a little warmer, I'll go in with my snorkel and facemask and GoPro and take some better pictures of some of the more 'discolored' areas. Should I be able to feel the scale? Does it feel bumpy?

pooldv · May 11, 2016

Yes, it feels rough like sand paper. Lowering your TA to the 60-80 range will help slow PH rise.

FloridaPoolGal · May 12, 2016

pooldv said:
Yes, it feels rough like sand paper. Lowering your TA to the 60-80 range will help slow PH rise.

I feel the slight roughness of the aggregate but I don't feel sandpaper on the walls. The water will have to warm up before I check the floor!

TA was 60 yesterday. I recalled reading about people shooting for a lower TA but 60 didn't keep me in the -0.1 to -0.3 range so I added baking soda. I was shooting for 80 and hit 90. I measured TA two weeks ago and I was at 80 so I have been sliding from 80 to 60 over the last two weeks.

Today's values
FC: 7.0
CC: 0
pH: 7.4
CH: 280
TA: 90
CYA: 60 (prior measurement)
Water temp: 76 degrees
CSI: -0.2 (right in the middle of the window suggested above)

If I put 10-12 ounces of muratic acid in every day, my pH would probably remain constant. Should I be putting a little acid in every day? I put chlorine in every day but I've never made acid a daily addition. Maybe I should.

pooldv · May 12, 2016

What happens if you put PH at 7.8 and TA at 60?