SLAM Issue, 5 days clear, can’t pass OCLT test.

caliskier

LifeTime Supporter
Aug 24, 2014
359
Oklahoma City, OK
Trying to SLAM, I’m on my fifth day clear, and it seems like we are still using a lot of chlorine. The pool has been scrubbed and swept several times. I’m looking for ideas as to what could be the issue, what am I missing? I have scrubbed out the skimmers, I have scrubbed out the rope anchors, pool bottom and walls are spic and span.

Tested last night at 9:30, added chlorine, tested again at 10:30 and FC was at 12. Tested this morning at 5:30 it was at 10.5.

Setting FC to 12 every 3-4 hours with a CYA value of 3.

What am I forgetting?
 

djdonte

Well-known member
Mar 25, 2019
325
Houston, TX
Do you have any water features? What delayed me on my slam was some hidden algae in the skimmers, the waterfall sump and finally the light niche.
 

caliskier

LifeTime Supporter
Aug 24, 2014
359
Oklahoma City, OK
Due to work and storms yesterday in my area i was unable to get the light niche off. Need to get into the pool to do it.

Ok, good morning. Getting inconsistent readings with my tests.

Last night at 9:30 I added chlorine, went out again at 11:00pm and tested. My readings were not consistent: 20, 23, 24, 24, 23, 24. This morning at 6:00 am, with dawn just beginning, sky navy blue, no sun, I get: 19, 19, 21, 22, 23. Note for this morning, the 19s were tested with slow drops, maybe at a rate of 3 drops every 2 seconds. the 23 was the fastest drop rate, maybe 3 drops a second. Water was taken from 4 different parts of the pool, last two tests were from the same cup of water.

What do I make of this? I have numbers that match, with the 22 to yesterdays 23's (can be off by 0.5 ppm) and the 23 with the 24's and the 19 with the 20. So actually if I tested once last night and tested once this morning I would think I was done. 20, and 19. I am not ready to call it good, but should i? Whats causing this?
 
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duraleigh

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You will be out of reagent VERY soon. There is no need to run the FC test more than once and then accept that as your FC......just do it carefully and accurately.

Stop taking your test from different parts of the pool, too. Your pump should be running 24/7 and your sample shouold be taken from the same locatioon every time.

Hold the R-870 bottle perfectly vertical and allow the drops to fall of the tip.....don't push them out. Secondly, the test is complete when the last drop you add results in NO FURTHER color change. Subtract that last drop from your total and the test is complete.

STOP all that wasteful testing. Run the test one time and call it good. You should get within .5 PPM of accuracy each time......the chlorine level doesn't change.

Should you call it good? I would not. Continue to hold your FC at SLAM value (up around 12) but now only test twice daily for a few days and then do another OCLT around Friday or so.
 

caliskier

LifeTime Supporter
Aug 24, 2014
359
Oklahoma City, OK
Thanks for the guidance how to test I was not doing it that way. Good point about waiting till Friday, that gives me some rest but I may still do it daily.

As for Regent, I have a bulk supply of it, But I understand what you’re saying no need to waste it it’s just odd that I am getting different numbers every time. I will test using your method.
 

caliskier

LifeTime Supporter
Aug 24, 2014
359
Oklahoma City, OK
You will be out of reagent VERY soon. There is no need to run the FC test more than once and then accept that as your FC......just do it carefully and accurately.

Stop taking your test from different parts of the pool, too. Your pump should be running 24/7 and your sample shouold be taken from the same locatioon every time.

Hold the R-870 bottle perfectly vertical and allow the drops to fall of the tip.....don't push them out. Secondly, the test is complete when the last drop you add results in NO FURTHER color change. Subtract that last drop from your total and the test is complete.

STOP all that wasteful testing. Run the test one time and call it good. You should get within .5 PPM of accuracy each time......the chlorine level doesn't change.

Should you call it good? I would not. Continue to hold your FC at SLAM value (up around 12) but now only test twice daily for a few days and then do another OCLT around Friday or so.

5 hours later and just did it your way, very slowly vertical, etc for the morning to bring back to slam level. You still have to squeeze to get something to come out. Came up with 18, 17 if I take off one point for the very last drop. And a question. Why subtract that last drop?
 

proavia

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Feb 6, 2015
1,885
Chandler AZ
5 hours later and just did it your way, very slowly vertical, etc for the morning to bring back to slam level. You still have to squeeze to get something to come out. Came up with 18, 17 if I take off one point for the very last drop. And a question. Why subtract that last drop?
Since the last drop made no further change, it doesn't count.
 

caliskier

LifeTime Supporter
Aug 24, 2014
359
Oklahoma City, OK
Since the last drop made no further change, it doesn't count.
Thanks,

Actually it did have a further change, it went from light pink pure white, so it counts correct?

Not to split hairs by any means but when you’re getting up at five in the morning for five days straight you really want to make sure every drop counts, lol
 
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duraleigh

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That could be a small contributor but it is likely not the total source of your chlorine loss. From the pic, I can't visualize exactly where that algae is. Is it in a corner on a vertical wall? It needs to be removed for cosmetic reasons as well as a source of chlorine depletion.
 

caliskier

LifeTime Supporter
Aug 24, 2014
359
Oklahoma City, OK
That could be a small contributor but it is likely not the total source of your chlorine loss. From the pic, I can't visualize exactly where that algae is. Is it in a corner on a vertical wall? It needs to be removed for cosmetic reasons as well as a source of chlorine depletion.
Thanks for your help brother, I’ve taken some better photos. These are my pool steps, The first picture below is the steps zoomed out, the left side is below that and the right side is in the post above. The left and right side, and the bottom have algae growing down along the “step” side of the liner strips that separate the steps from the liner.
The algae is growing under the caulk so I can’t scrub it out.

A3DFB206-ACCC-4D83-A0BB-370592B9D6BC.jpegF324B701-8453-44B3-BCD6-ED76E3322B3E.jpeg
 
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duraleigh

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good pics, I got it now. I would buy a natural (boar bristle) deck brush and methodically scrub that blackened are every chance you get. It may take a while but you should be able to minimize it or fix it.

I am reluctant to suggest a dose of acid or chlorine because I don't know what that vertical bar is made from and both will hurt your liner. A little Soft Scrub would be alright if you can keep it in the brush. It will take you a long time to fix this up but it has been neglected a long time. Black algae is hard to get started but it's hard to get rid of it once it gets a foothold.
 

caliskier

LifeTime Supporter
Aug 24, 2014
359
Oklahoma City, OK
Thanks again, what I was actually thinking, the liner is less than a year old. I actually installed it myself. That said I thought about draining it just below the top of the bottom strip going across. Ripping out all the caulk, and then going back in with pool puddy. This stuff. That caulk really doesn’t need to be there it is just Insurance because this is a plaster part of the pool and it’s a little bit porous and I think it leaks there. When I pulled the liner last year and replaced it there was a lot of algae growing up underneath the liner leaking around the steps. The pool puddy will probably look a lot better, will fix the algae and still prevent leaks.
 
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