Can't Get Cya Reading

[sandsquid]

I started to opened my pool about 2 weeks ago, and my water levels were better than expected. I had a issue with my sand filter automatically backwashing while it was on filter which resulted in the chemicals being wasted and no circulation. Once I discovered the backwash issue and resolved it, my pool started growing algae and turned a hint of green. I instantly put in 3lbs of shock for my pool size approx. 12000 gallons. Then the water became cloudy (no longer green). I am still seeing very small amounts of algae heading towards the skimmer, but I still keep fighting that issue as well (trying to shock the you know what out of it) and now the cloudy water issue. My readings are not changing and I am not able to get any kind of CYA reading. I am stuck and not sure how to proceed. Any suggestions would be greatly appreciated. Thanks!

TC	FC	pH	TA 	TH	CYA     Date	        Time	Notes:
1	0.5	7.5	120	300	0	6/19/2010	1630	Vacuumed @ 1600 - Added 3 lbs of Shock at 1722 (full sun)
2	1	7.4	120	300	0	6/20/2010	1430	vacuumed @ 1330 - added stabilizer condition at 1500 2 lbs. - added clarifyer @ 1530 - vacummed walls @ 1630 (full sun)
0.5	0.5	7.4	120	300	0	6/21/2010	1800	Add 128oz bottle of liquid clorinator and 1lb of stabailzer at 1830 (overcast partly sunny)
0.5	1	7.5	120	300	0	6/22/2010	1950	Full Sun temp. 95

[polyvue]

I started to opened my pool about 2 weeks ago, and my water levels were better than expected. I had a issue with my sand filter automatically backwashing while it was on filter which resulted in the chemicals being wasted and no circulation. Once I discovered the backwash issue and resolved it, my pool started growing algae and turned a hint of green. I instantly put in 3lbs of shock for my pool size approx. 12000 gallons. Then the water became cloudy (no longer green). I am still seeing very small amounts of algae heading towards the skimmer, but I still keep fighting that issue as well (trying to shock the you know what out of it) and now the cloudy water issue. My readings are not changing and I am not able to get any kind of CYA reading. I am stuck and not sure how to proceed. Any suggestions would be greatly appreciated. Thanks!

Welcome to the forum.

A few questions: What is the current pressure at the filter in PSI (or bars)? What product are you using to shock with (brand name, ingredients)? What do you normally use to sanitize (chlorinate) your pool?

You said that you weren't able to get a CYA reading but you didn't say why. Best (most accurate) results would come from a test kit but if you have to, take a water sample to a nearby pool store and have them provide a full set of test results, including CYA:

pH

Free Chlorine (FC)

Combined Chlorine (CC)

Total Chlorine (TC)

Total Alkallinity (TA)

Calcium Hardness (CH)

Cyanuric Acid (CYA)

Salt PPM (if this is a salt water pool)

Knowing the level of CYA is critical because of its relationship to the right level of chlorine needed to shock and kill algae. It's quite common after shocking at inadequate levels for algae to keep coming back. But this problem can be addressed.

[sandsquid]

Thanks Polyvue. My current pressure at the filter is 10 PSI. When it gets to about 20 PSI, I typically backwash it.

I am using HTH Shock 'n Swim #3 with CALCIUM HYPOCHLORITE 47.6%, OTHER INGREDIENTS 52.4%, TOTAL 100%, MINIMUM AVAILABLE CHLORINE 45%. (43% Potassium Monopersulfate)

(that's all I can find for ingredients)

I use HTH Liquid Chlorinator with SODIUM HYPOCHLORITE 10%, OTHER 90%, once the pool gets balanced, then I will use the HTH hockey pucks.

I believe I am getting a CYA reading, however it appears to be very low and doesn't even come close to the colors on the strips. I will try a different brand of test strips to see if there is any difference. I am not sure why I wouldn't be getting a CYA reading, or why it would be very low.

I went and checked on the pool this morning first thing. I do not see any more algae at the surface like I had been seeing. I think I may have won that battle.

[chem geek]

I believe I am getting a CYA reading, however it appears to be very low and doesn't even come close to the colors on the strips. I will try a different brand of test strips to see if there is any difference. I am not sure why I wouldn't be getting a CYA reading, or why it would be very low.

Do not try a different brand of test strips. They do not measure some things accurately and are often wrong with the CYA test. Please get yourself the Taylor K-2006.

[polyvue]

Thanks Polyvue. My current pressure at the filter is 10 PSI. When it gets to about 20 PSI, I typically backwash it.

I am using HTH Shock 'n Swim #3 with CALCIUM HYPOCHLORITE 47.6%, OTHER INGREDIENTS 52.4%, TOTAL 100%, MINIMUM AVAILABLE CHLORINE 45%. (43% Potassium Monopersulfate)

(that's all I can find for ingredients)

I use HTH Liquid Chlorinator with SODIUM HYPOCHLORITE 10%, OTHER 90%, once the pool gets balanced, then I will use the HTH hockey pucks.

I went and checked on the pool this morning first thing. I do not see any more algae at the surface like I had been seeing. I think I may have won that battle.

You've probably read here that liquid ("pool") chlorine or 6% bleach is a better way to chlorinate and/or shock pool water. The "other ingredients" in the products you cite are often unnecessary or even counterproductive. If you find a recurrence of algae in your pool, please consider buying a good test kit and read this article, which outlines a very effective procedure for defeating algae. Here's another article that may be helpful.

The process involves shocking the pool with liquid chlorine according to the concentration of Cyanuric Acid (CYA) that is in the pool. Rely on the Best Guess CYA chart to determine the amount of chlorine to shock with.

The prospects for a first-time success is improved by the use of a good test kit (the Taylor K-2006 is discounted by various on-line sources, including that linked by chem geek, above). Welcome to the forum. Feel free to post back with any questions you may have.