SLAMming a clear pool

bmj0928

Bronze Supporter
Jun 25, 2020
48
Pittsburgh, PA
FC loss of 5 overnight. Still going.
I cleaned behind the light, which was still clean from the last time I cleaned it, and under the main drain cover, which was dirty and full of dead algae (it's plugged, and non-functional). The cart. filter was cleaned this past weekend. Wondering if it needs to be cleaned more often? The pressure has not gone up at all.

We did have a storm roll through on Tuesday that threw a lot of debris in the pool, but I cleaned that up pretty quickly after. I also added water yesterday, because the water level had dropped an inch.

I wish I could scrub the return plumbing, but that doesn't seem practical.

Otherwise, the pool is amazingly clear, and CC is not rising above 0.5.

Question: does running the pool heater affect chlorine? Does the chlorine break down when it goes through the heat exchanger?
 
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CrystalRiver

Well-known member
Jun 19, 2020
290
Massachusetts
The cart. filter was cleaned this past weekend. Wondering if it needs to be cleaned more often? The pressure has not gone up at all.
Anectdotally, I can tell you that my SLAM really turned a corner when I started backwashing daily regardless of the pressure. I was stalled for about two weeks, pressure not going up at all, water not improving, when I decided to backwash for the heck of it. And oh MY was that water dirty!

I realize cleaning a cartridge filter is a lot more work than backwashing, and your water is clear whereas mine was opaque. But I think it's worth opening up and taking a look.
 
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bmj0928

Bronze Supporter
Jun 25, 2020
48
Pittsburgh, PA
Another OCLT loss of 4 this morning. Just acid washed the filter cartridges. That was no fun, but the acid water was really nasty. Grayish, brownish milky waste water.

The back pressure in my filter dropped about 30%.
 
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bmj0928

Bronze Supporter
Jun 25, 2020
48
Pittsburgh, PA
Before the SLAM, I had a CYA of 50. Using only liquid bleach for the SLAM, my cya is now 80. Can I trust a cya measurement when slamming? Do I need to drain some water and refill?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,281
Laughlin, NV
CYA only goes up if you add it to the water.

Could be test error with either test. Re do the test later. Be sure to pour the contents back into the bottle and redo the test multiple times to get an average.

Elevated FC levels have no effect on the CYA test.
 
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bmj0928

Bronze Supporter
Jun 25, 2020
48
Pittsburgh, PA
CYA only goes up if you add it to the water.

Could be test error with either test. Re do the test later. Be sure to pour the contents back into the bottle and redo the test multiple times to get an average.

Elevated FC levels have no effect on the CYA test.
Thanks. I actually think it was an error with the initial test. I just retested 3 times and then did the 50/50 tap water to pool water CYA test
, and all tests came out to a cya of 80.

This may explain why the water looked a little cloudy after my family and I spent most of yesterday in it.
 
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bmj0928

Bronze Supporter
Jun 25, 2020
48
Pittsburgh, PA
Increased SLAM yesterday with higher levels. OCLT loss of 3, but the pool is looking even better than before. The kids used the pool yesterday, and it clouded sightly. Did a thorough stainless steel brush and vac last evening before increasing sanitizer to 31 ppm. Lots of white and gray "puffs" were lifted up while brushing.

I hope that scrubbing and vacuuming today has good results. The yellow-brown-orangish tint that was covering the walls and bottom is now nearly gone.

The only issue with high chlorine levels isn't maintaining high chlorine, but now I'm going through reagents lightening fast. Once the chlorine is elevated, it's easy to maintain that high level. But, 62 drops of R-0871 per test is a lot of drops!
 
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Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,930
San Dimas, CA (LA County)
Increased SLAM yesterday with higher levels. OCLT loss of 3, but the pool is looking even better than before. The kids used the pool yesterday, and it clouded sightly. Did a thorough stainless steel brush and vac last evening before increasing sanitizer to 31 ppm. Lots of white and gray "puffs" were lifted up while brushing.

I hope that scrubbing and vacuuming today has good results. The yellow-brown-orangish tint that was covering the walls and bottom is now nearly gone.

The only issue with high chlorine levels isn't maintaining high chlorine, but now I'm going through reagents lightening fast. Once the chlorine is elevated, it's easy to maintain that high level. But, 62 drops of R-0871 per test is a lot of drops!
Then use 5 ml and each drop is 1. But don't do that for the OCLT.
 
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bmj0928

Bronze Supporter
Jun 25, 2020
48
Pittsburgh, PA
Drop of 3 for the OCLT last night, and the "staining" is fading even more. It is amazing that it does not come up brushing with a steel brush, but after I brush, vacuum, and add sanitizer to SLAM levels, the next day I notice a difference. This must have been a long standing problem I never realized was so bad. The water is sparkling clear, but the SLAM continues. I have to be getting close to the end.

I may do a partial drain and refill, though, because the amount of chlorine and reagent I am using with a CYA of 80 is too much.
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
4,425
Fletcher, OK
CYA of 80 is up there unless you have a salt water generator, then its perfect... But when you pump breaker shuts off for 30 hours before you notice it I had to do a 2 day SLAM, I know exactly what your dealing with :)

The nice thing is once you have passed the SLAM/OCLT you will see just how clear and great your pool will look and you notice instantly when it gets a little hazy...
 

poolnoobgrandma

Gold Supporter
Sep 15, 2018
479
Seminole, FL
CYA of 80 is up there unless you have a salt water generator, then its perfect... But when you pump breaker shuts off for 30 hours before you notice it I had to do a 2 day SLAM, I know exactly what your dealing with :)

The nice thing is once you have passed the SLAM/OCLT you will see just how clear and great your pool will look and you notice instantly when it gets a little hazy...
Exactly! My only daily test is looking at my sparkling water!
 

bmj0928

Bronze Supporter
Jun 25, 2020
48
Pittsburgh, PA
After an overcast day yesterday and some rain the day before, my FC level only dropped 2 overnight last night, but my CC increased 1.5. I will say, though, the pool looks brighter than ever, sparkling and clear this morning. I plan to brush, scrub down hidden areas, vacuum, and clean the filter carts today. Hopefully I can end this SLAM soon. My POP is starting to wear a little thin.
 

bmj0928

Bronze Supporter
Jun 25, 2020
48
Pittsburgh, PA
Today is an exciting day for me, TFPers. Today I end my SLAM. Last night I had a drop of 1 ppm and my CC is 0.5. I believe I had a mustard algae problem, so today I am following the mustard algae slam process, and super duper chlorinating for 24 hours, according to this chart: Chlorine/CYA Chart Even if I didn't have a mustard algae problem, I don't think it hurts to treat it as if it was for 1 more day.
Edit: I read on another thread that I should maintain elevated FC levels for a while longer.

I started the SLAM on July 29th, almost exactly 1 month to the day. It seems much, much longer.
46 gallons of bleach later ($125), I will be letting the sanitizer levels mellow starting tomorrow morning. It seemed ridiculous buying up all of Lowe's pool bleach (the 10% stuff), 12 gallons at a time, but the cost of liquid bleach is really low compared to anything the pool store was recommending, and way less expensive and damaging than powdered shock and tablets.

The result? ALL staining i had seen is now gone. Everything. I thought I had iron in my water because my pool bottom had brownish/yellow streaking, but that staining is gone. I thought I had calcium scaling because certain areas had grayish deposits, but that is gone. I thought the white plastic parts were just old and experienced color change naturally because they are old... that color change is gone. Even my skimmer that had gone deep yellow/orange is now gleaming white. The white, fiberglass walls had a certain tinge to them... they are now bright white.

Edit: I forgot to mention that something strange happened during the slam. The "yellow / brown staining and streaking" on the bottom turned into what I thought was faded paint. I thought it was strange that my paint faded exactly where the staining was, but thought the combo of chlorine and sun was responsible. Only in the last few days did that go away. Now, I think it was probably the remaining algae giving up the ghost.

Probably the most impressive change, though is the water itself. It was clear before the SLAM, but took on a new sheen. Now, it is so clear that at night, when a dim light color is on (like red, or deep blue) and the filter is off, the water becomes invisible. It creates a trippy illusion as the bottom is magnified and "moves" as I walk around it.

Lesson Learned:
- I wish I had really taken the advice of getting my CYA low before the SLAM. 50 is the absolute maximum. 30 would have been better. I'm at 40 after 2 partial drains (down from way over 100).
- I wish I would have stocked up on reagent, especially R-081. I went through about 4 bottles of it. My advice is to buy 5 bottles the day you begin the SLAM. tftestkits sells a sanitizer testing bundle. Buy 1 bundle and 4 bottles. Even though they ship fast and I was able to get my refills in about 3 days, there were days when I had to trust that pool math was correct on the effects of adding certain amounts of bleach.
- Pro Tip: Scratch a line at the 10 mm mark of the testing beaker before the marks wear off. All of my marks wore off during the slam.
- Brushing matters as much as vacuuming. A stainless steel brush is a must for concrete. Keep your water line tiles clean, too (I used a scotch bright pad on those)
- Remove pool parts and scrub them down once a week. The first time I removed my light I unleashed what looked like an Alaskan Sea Kelp forest into my pool: yellow, feathery algae, black spots on the niche. My non-functioning main drain was also hiding all sorts of grossness. Don't forget to scrub down the hidden areas of the skimmer. I used a scotch bright pad and a screwdriver to get into the corners.
- My plumbing even had a yellow/orange coating. I cleaned the pipes I could get to, but trusted the chlorine would get what I couldn't.
- Throw away your tablet chlorinator. They are only trouble. I bought mine 2 years ago. It's now sitting on the shelf, full of yellow scale. I should post a picture. The expensive Clorox "Xtra Blue" tablets and shock treatments I was using lifted my CYA to an unmanageable level, and gave me the illusion that I was sanitizing my pool properly.

Thank you TFPool forum members, especially the experts and Lifetime Supporters. Your knowledge saved me a ton of frustration and money at the pool store.
 
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cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
4,425
Fletcher, OK
Isn't it a GREAT feeling when it works in the end... Tonight when you do the OCLT lets make sure you do not lose more than 1ppm and still have a CC of .5, that will mean you are still fighting something. something is hanging on for dear life and you do not want to stop 2 feet from the finish line...

I am very happy you made it :) :whoot:
 
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duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
34,426
Sebring, Florida
I may be misinterpreting cowboycasey's post above but a cc test results of .5 ppm is perfectly acceptable......TFP treats that result exactly as if were zero ppm.
 

Newdude

Well-known member
Jun 16, 2019
4,566
NY
I may be misinterpreting cowboycasey's post above but a cc test results of .5 ppm is perfectly acceptable......TFP treats that result exactly as if were zero ppm.
A loss of 1 FC and .5 are acceptable due to the testing not being 100.000000% accurate. IMHO I don’t want to barely pass, I want to pass with flying colors. Tomorrow’s test may very well pass with a perfect score due to my errors or a ever so slightly more accurate test on the 2nd attempt. But it takes a ton of work to get to that point and just a little work to let it ride for one more day so to me it’s worth it.