CYA SLAM and CC

SupaDave

Bronze Supporter
Nov 25, 2016
28
Tampa, Florida
#1
after coming upon TFP, I found my CYA levels to be over 100 or so due to my inexperienced use of tabs. After (2) 75% drain and refills, I had my CYA down to what I believe to be approx. 60. I had been religiously been keeping my free cl levels at the recommended levels, but somehow noticed some patches of yellow looking stuff on my pool bottom which I assumed was algae. Thought maybe my CYA was still a little high, I did another 75% drain and refill and currently have my cya down to what I believe to be 35-40. I am subsequently going thru a SLAM, trying to keep my free cl level at approx. 20 slam level. I am losing approx. 3-4 ppm free cl overnite, but consistently test no combined chlorine. We haven't had a lot of sun over the last several days, so I'm wondering what is eating my cl? More questions.... Is it possible to have something organic eating my chlorine but show no combined chlorine? If I show no CC, does that mean I have no organics? I realize my CYA is a little low and am trying to raise it via judicious use of tabs, is this realistic? Also, I read on here somewhere, that one tab raises cya by 9ppm. Can someone explain how that correlates with the readings on my taylor fas-dpd kit? And lastly, Is there any other way to test cya other than this black dot deal, as it seems very subjective, unlike a color change test.
Thanx,
Dave.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
36,659
Tallahassee, FL
#2
CYA test-the way I found that works best for me is to GLANCE in the tube. Do not stare. Just a quick glance in the look away. I pour from line to line. Pour to first line (100) glance in. If I see the dot I pour to the next line. I keep doing this until I do not see the dot at a GLANCE.

Have you been brushing your pool? That really helps get everything up and out into the water for the FC to get to it.

Light? Ladder? Think about removing them to clean under, around, behind.

Look close at skimmer door and around returns. Sometimes stuff gets stuck there.

I THINK the tablets only add about 2 ppm of CYA. Use pool math and see what it says. There is a place to see what does what to your pool.

We are going to have to really watch our water early this year due to the warmer weather already being here.

Kim:kim:
 
Mar 24, 2014
2,091
Greenville, SC
#3
Chlorine is consumed by UV and organics. If you are losing 3-4 ppm FC overnight, you have organics. 0 CC does not mean organic free.

Don't raise CYA until the SLAM is done. Yes, the black dot test can be difficult, but it's what we have to work with. Just be sure to do it in full sunlight, back to the sun, vial at your belt buckle. What I do is pour it back into the squirt bottle and retest 2-3 times and average what I get. +/- 10 is close enough.

Can you post a full test (pH will be invalid with high FC, so whatever it was before you started SLAMming will be fine) and what your SLAM schedule is (frequency of testing and adding).
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,388
Sebring, Florida
#4
Good advice above. I'll repeat, "Have you been brushing?"

The SLAM process is a whole lot more than just adding chlorine. It is brushing, vacuuming, cleaning your filter, etc.

Re-read Mr Bruce above. He offers a good understanding of FC and CC. Please read "The "ABC's of Pool Water Chemistry" up in Pool School. It'll fill in some of the basic issues you need to know.

Keep with it. You will soon have a crystal pool and we'll help if needed.
 

woodyp

Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
10,228
East Texas
#5
"After (2) 75% drain and refills, I had my CYA down to what I believe to be approx. 60. I had been religiously been keeping my free cl levels at the recommended levels, but somehow noticed some patches of yellow looking stuff on my pool bottom which I assumed was algae. Thought maybe my CYA was still a little high, I did another 75% drain and refill and currently have my cya down to what I believe to be 35-40."

THREE (3) 75% drain and refills?????.........and still 30 to 40 cya? Testing procedure must be WAAAAY off somehow or another. I'd get another set of eyes on that testing if you can.