SLAM continues. Target is 16 and dropped to 10 overnight. I'm at a loss. I've scrubbed everything I can, even taking the filters out again and cleaning them (they weren't very dirty).
Time to drain the pool...
- Thread starter GMTK
- Start date
- Jun 22, 2014
- 47,908
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Yikes! That's a large drop. Do you have any hollow spots or niches in the pool? Steps, railings, under a drain cover, behind a light perhaps? Did you confirm that last night's FC was 16 after adding the required bleach? Any chance of a testing error?
We have some steps and a rock over-hang but I scrub them well and checked them (while in the pool) for any signs of algae. I did NOT confirm the 16 last night after adding bleach (around 8pmish). I pulled my skimmer baskets out and made sure they were empty and bleached them. Same for the basket on the pump.
I've gotten pretty good with the tests since I'm doing it 3-4 times a day.
Maybe I've got hidden algea in a pipe somewhere? I'm running the main pump 24/7 and the waterfall pump for 6-7 hours also.
I've gotten pretty good with the tests since I'm doing it 3-4 times a day.
Maybe I've got hidden algea in a pipe somewhere? I'm running the main pump 24/7 and the waterfall pump for 6-7 hours also.
- Jun 22, 2014
- 47,908
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
It could just be that your chlorine/bleach didn't reach the goal you assumed. That's very possible. Plus, we still have daylight until about 8:30-8:45, now that our days a re getting longer. Perhaps a little FC got burned-off by the sun. I would be careful about those two things and try again.
Also, maybe post a pic of your pool?
Also, maybe post a pic of your pool?
how long after adding chlorine at dusk should I wait before testing? An hour?
- Jun 22, 2014
- 47,908
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
That is a very nice set-up you have there. 
Water looks fantastic too. As for testing after adding chlorine, about 30-45 minutes in your pool with good pump circulation should do it. An hour is fine as well. The important thing is that the sun is down. We usually leave the pump on overnight as well (SLAM mode), but if yous is off for some reason overnight, turn it on in the morning let the water mix for about 30-45 minutes before taking the morning sample.
Water looks fantastic too. As for testing after adding chlorine, about 30-45 minutes in your pool with good pump circulation should do it. An hour is fine as well. The important thing is that the sun is down. We usually leave the pump on overnight as well (SLAM mode), but if yous is off for some reason overnight, turn it on in the morning let the water mix for about 30-45 minutes before taking the morning sample.
It appears you are preparing to do an OCLT test tonight. Why are adding chlorine just before the test. That is probably not a good practice. What is your current FC? Hold on the OCLT for now. Post you current FC, please.
I thought the goal of the OCLT test was to have a set number at dusk, and you want that number to match in the morning? So what I have been doing on my last test of the day, get my FC (at dusk) and then add to get back to 16 FC. (But I have not been testing to ensure I am hitting 16).
Just tested and FC was 10, with a target of 16. So I added per the Poolmath rec.
Just tested and FC was 10, with a target of 16. So I added per the Poolmath rec.
Flying Tivo
TFP Guide
- Jan 24, 2017
- 2,967
- Pool Size
- 7500
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Lets clear this. Today after sundown test your FC, do not add anything and record your reading. Leave the pump running. Before sunrise test for FC and record your reading. Thats it, no fuss. Post your results.
- Jun 22, 2014
- 47,908
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
GMTK, I believe the some posters may not realize you are actually in the middle of a SLAM. That's why you were trying to maintain an FC of 16 (CYA of 40). If the SLAM wasn't an issue, you could essential have just about any FC you wanted before the end of the evening to perform an OCLT. Just wanted to make sure everyone was aware of that one. But your water looks exceptional with relatively no CC. It's unclear why you lost 6 ppm of FC last night, but if you wish to start the OCLT this evening with a lower FC, that is certainly your choice. It's getting TX hot today, stay cool. 
Yep, I am confused. GMTK, are you getting ready to perform an OCLT test tonight or are you simply in the middle of the SLAM process?
I am on Day 9 of my SLAM and was going to to the OCLT tonight. My pool is crystal clear and my CC is 0.0; so per the SLAM page I just need to have a good OCLT and I can stop the SLAM process.
That is correct. Do not add any chlorine tonight, Just test carefully after the sun is off the pool, keep the pump running overnight, and then test again before the sun is on the pool. I'll bet you pass.
Just tested, did it three times...Varied from 9.5-11.5 (9.5, 11,11.5). Will test before the sun comes up.
I did not add any cholrine.
And I'm using R-0870 powder with R-0871 titrating liquid.
I did not add any cholrine.
And I'm using R-0870 powder with R-0871 titrating liquid.
- Jun 22, 2014
- 47,908
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Not sure if we ever asked this one... do you use the speedstir? And you are using the 10 ML sample size with one scoop right?
I don't have a speed stir. I have been using 10 mL with two scoops (my directions don't say to use one scoop for 10 mL.
There is no point in doing the final portion of the OCLT this morning......your tests last night were wa-a-ay to imprecise to perform the morning portion of the test.
So, for now, I would suggest you return your FC to the 16 ppm SLAM level and continue the SLAM for another day or so.
The chlorine test you are doing is the most precise test in the kit and MUST be done very carefully and precisely.
The dropper bottle should be held perfectly vertical and the drops allowed to "fall" off the tip.......this ensures a uniform drop size.
You should be able to get the same result with each test (+ or - ONE drop).
The endpoint of that test is tricky......you continue to add drops slowly until THE LAST DROP YOU MAKE produces NO FURTHER color change of any type. Then you subtract that last drop from your total, but you must keep going until you get NO FURTHER color change.
As long as your powder turns the sample pink, that is enough powder......the exact amount is not critical.
So, for now, I would suggest you return your FC to the 16 ppm SLAM level and continue the SLAM for another day or so.
The chlorine test you are doing is the most precise test in the kit and MUST be done very carefully and precisely.
The dropper bottle should be held perfectly vertical and the drops allowed to "fall" off the tip.......this ensures a uniform drop size.
You should be able to get the same result with each test (+ or - ONE drop).
The endpoint of that test is tricky......you continue to add drops slowly until THE LAST DROP YOU MAKE produces NO FURTHER color change of any type. Then you subtract that last drop from your total, but you must keep going until you get NO FURTHER color change.
As long as your powder turns the sample pink, that is enough powder......the exact amount is not critical.
Ok, will continue the SLAM. Tested this morning (did it twice) an got 8 ppm (both times).
- Jun 22, 2014
- 47,908
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
GMTK, it can be really tough to swirl and add drops at the same time I'm not kidding when I say the Magnetic Speedstir is one of the best tools in your test kit. You should get one as soon as possible to make your testing that much more easy and efficient. Makes a big difference. 