Pool Testing Problem

[Jimbolo]

Hello All, I've had a couple of spots on the walls of the block border to my pool that had what looked like heavy calcium "leaking" out. The spots were hard white that ran down the block.

So I put about 6 oz. of muriatic acid in a spray bottle and started at them. Got most of it off.

But then in the afternoon I ran my pool chemistry and had some problems. The CC test had results that were darker red than what was on the scale. I tried to test the calcium hardness to see if that was causing the buildup (and the hair like straw issue), and I was at 100 drops of the third chemical and the water was still not blue (as the test says it should turn).

I'm stumped. The water otherwise is crystal clear. I use a tab feeder for chlorine and shock any time we get significant rains. Temps have been in the 90's.

Any ideas?

Thanks for this and all of your help!!

Jim.

 

[JasonLion]

Which test kit do you have? It sounds like you are using a DPD test, since that is the one that turns the sample various shades of red and then compares to a color chart. The DPD test measures FC and TC. Do you mean that the TC color was darker red than anything shown on the color chart/standard?

 

[Jimbolo]

I wish I could tell you what the name of my kit is. I got it with the house but have seen the same kind at the pool store. About $80. It tests all chlorine, ph, calcium harness etc.

About the chlorine test: yes, when I run the test the color of the comparator is darker than any of the samples, the highest being 10.

As far as the calcium hardness test, I had to add drops of one bottle then swirl to turn pink. I then had to add differentdrops, counting, until the water turned blue to get my hardness (drops multiplied by 10). I was up to 100 drops before I quit.

I use the complete tabs in my feeder that supposedly manage CYA. It rained hard yesterday further messing my water up.

I think it's probably been several years since the water has been replaced. During the summer here, evaporation is high, so several years of replacing 30-40 gallons of week for most of the year would add up to some serious mineral residual, I would imagine.

I need to get my facts straight and post from home where I have the information. I not giving you all much to go on. Sorry!

Thanks, Jim.

 

[JasonLion]

Try doing the chlorine test with a mixture of equal parts of pool water and chlorine free water (for example distilled water). When doing the test that way you need to multiply the result by two.

You didn't say where you live. If you live in an arid part of the country and have high CH fill water it is possible for the CH level to get extremely high because of evaporation. Water that evaporates leaves all the CH in the pool, and then water used to top off the pool brings more CH along with it, so the CH level just goes up and up. In this kind of situation, it is good to known your fill water CH level.

Posting a full set of water test results would help.

 

[Jimbolo]

Hi Jason, I really appreciate all of the help.

Here is the best of my information:

My test kit is a Taylor K-2005 (got it with the house, in good condition)
Free Chlorine - Too high to test. Water was dark pink, almost double the shade of the 5ppm comparator block.
CYA - Too high to test. Filling the small tube until the black dot was no longer visible left the water level about half way up to the 100ppm mark on the back of the tube.
Calcium Hardness - Too high to test. At adding R-0012 until the water turned blue, I stopped at 100 drops, which was about half my bottle.
TA - 120ppm
Ph - 7.6-7.8

We even got a good rain, which should have diluted the chlorine.

Should I drain 2/3 of the pool and start from scratch?

Thank you so much for taking the time to work through this with me. Everything I know about my pool (which is not much but tons more than when I started 2 months ago) I learned from you all here.

Jim

 

[JasonLion]

When measuring high CH levels, you can use a 10 mL sample, 10 drops of R-0010, 3 drops of R-0011L, and each drop of R-0012 then counts as 25 ppm. This is handy if your hardness is very high, and it saves on reagents.

Replacing water sounds like a great idea. CH and CYA are both high and both need to come down.