Help! Testing for the first time.

[Aggiechica]

We bought a new house in October with an inground plaster pool. I am committed to maintaining it myself. I had been using test strips and shock, and whatever else I would find online about what to do to take care of whatever my current issue was. I found this site and am really excited to learn how to REALLY maintain my pool the right way. I just bought the TF-100 Kit and got my results from testing. I'm really not sure what I need to do next. Here are my results:
FC: 11.5
CC: 1.0
pH: 7.5
TA: 100
CH: 300
CYA: 100 (if there were more lines on the cylinder it would have probably been more like 110)

I'm constantly fighting algae growth on the walls.
Any help you can give me on where to start would be great.

Christa in CA

 

[Texas Splash]

Congrats on the new home, pool, and test kit. Your #1 priority is to get the CYA under control. To get a better idea of how high that CYA really is, you should do a diluted CYA test using the link below starting at Step #8. I know many areas are under water restrictions, but the only way to lower CYA is to change some water. If you have any tabs is use remove them right away.

CYA - Cyanuric Acid Test

Cyanuric acid (CYA) is the chemical name for the product commonly called “pool water stabilizer” … Read more…

www.troublefreepool.com

Here is another page with some draining options in case it helps. But you definitely need that CYA down to about 70 or below. Simple CYA math - changing 50% of the water lowers the CYA in half. Let us know if you any questions.

Draining - Further Reading

www.troublefreepool.com

 

[Mdragger88]

Welcome to TFP
Like Tex said,
Do the diluted cya test to determine just how high your cya is & how much water u need to exchange.
then after refilling you will need to do the SLAM Process with liquid chlorine to eradicate the algae.

 

[Aggiechica]

Congrats on the new home, pool, and test kit. Your #1 priority is to get the CYA under control. To get a better idea of how high that CYA really is, you should do a diluted CYA test using the link below starting at Step #8. I know many areas are under water restrictions, but the only way to lower CYA is to change some water. If you have any tabs is use remove them right away.

CYA - Cyanuric Acid Test

Cyanuric acid (CYA) is the chemical name for the product commonly called “pool water stabilizer” … Read more…

www.troublefreepool.com

Here is another page with some draining options in case it helps. But you definitely need that CYA down to about 70 or below. Simple CYA math - changing 50% of the water lowers the CYA in half. Let us know if you any questions.

Draining - Further Reading

www.troublefreepool.com

When I did the diluted CYA test, it looks like my CYA is at about 80. So I did the regular CYA test to see if I was seeing things and I still got the same result as my original test...about higher than 100. So which do I go by?

 

[Mdragger88]

Did u multiply the diluted result by 2?
Did u stop seeing the dot @ 80 or 40 during the diluted test?

 

[Aggiechica]

Did u multiply the diluted result by 2?
Did u stop seeing the dot @ 80 or 40 during the diluted test?

Ahhh...I forgot to multiply by 2. I guess my CYA is actually at 160. Makes sense now. I drained a few inches this evening. Looks like I'm going to need to drain a lot more! Random question...what makes the diluted CYA test a more accurate measure of CYA? I guess my organic chemistry class in college didn't do me much good. l

 

[Mdragger88]

Ahhh...I forgot to multiply by 2. I guess my CYA is actually at 160. Makes sense now. I drained a few inches this evening. Looks like I'm going to need to drain a lot more! Random question...what makes the diluted CYA test a more accurate measure of CYA? I guess my organic chemistry class in college didn't do me much good. l

The cya tube is only so big- as it is made for the most common values- so after 90 ppm it isn’t quite accurate, thus the need for the diluted version when measuring above that.

 

[Mdragger88]

You may wanna check out the no drain water exchange in the draining article that @Texas Splash posted.

 

[Mdragger88]

It looks like u need to exchange roughly 70% of the water to get to a place that make the SLAM Process feasible.

 

[Aggiechica]

I did the water exchange and got my CYA to 45. That was done by Saturday evening. Last night I checked the pH and needed to lower it a bit. I then poured 3.3 gallons of 10% liquid chlorine in the pool late last night. Tested this morning and the FC was at 20.5 (slightly higher than the target of 18...I'm wondering if my my size estimate of 22000 gallons is a little high.) I was pretty excited to get the SLAM going. I measured FC again this evening after the sun went down and it is at 18.5. I think that's a good thing right? Some chlorine loss due to sun, but not much else? I am going to do the OCLT in the morning to see if my FC maintained overnight. If it has, then I think my SLAM is complete.

We are headed out of town tomorrow afternoon (Monday) and won't be back until Thursday night. With such high FC levels, should everything be ok to leave it untouched for a few days. Is my chlorine high enough that I don't need to worry about putting tabs in a floater? I have learned my lesson and don't ever want to get my CYA to crazy high levels again!

 

[Texas Splash]

With such high FC levels, should everything be ok to leave it untouched for a few days. Is my chlorine high enough that I don't need to worry about putting tabs in a floater?

Your pool will be fine with the elevated FC level. Monitor how much it falls from yesterday to today. That will give you an idea how long the FC will hold from SLAM level until you get back. You may need to use tabs or have someone add some liquid chlorine while you are away.

 

[Mdragger88]

If your dot disappeared between 40 & 50 you round up & call it 50. Always round up - there are no inbetweens on the cya test.
Slam level fc is 20ppm for a cya of 50
FC/CYA Levels

 

[Mdragger88]

This is the effect each dissolved 8oz tab will have on your water.
A couple will be ok.