First SLAM - Is This How it Goes?

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B

blackout

Gold Supporter
Jun 16, 2019
54
Upstate NY
Pool Size
16400
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
First year with the new pool, following TFP methods since the TF-100 showed up. I've only ever put into the pool CYA (once) and a little bit of liquid chlorine while I waited for the SWG to get fired up. My CYA has been 75-70 every measurement so far, and my FC levels have been 7-9 every test except one, where I was at 5 (all my logs are in PoolMath).

On Thursday afternoon towards the end of the workday I went out and pulled the cover off for the family and I saw cloudiness. It wasn't terrible; I could see the drains in the bottom of the deep end, but I immediately ran a test and I was at 0 FC. I ran to the closest grocery store to grab bleach and took out the cartridge filters to give them their first cleaning (pressure still hadn't gone up to warrant a clean, but I figured why not). Based on my CYA of 70 I set my target at 28 and poured it in. While I waited I went to Walmart and grabbed some of their 10% pool chlorine (date stamped 182, so fresh) and added a little more, ultimately landing at 31 before the end of the night.

By the next morning, the pool was completely clear, though I lost 6.5 FC in about 8 hours (.81/hr) and CC was at 1.0. After Friday night (night 2), I lost only 4.5 FC and was at a CC of 0.5 after 10 hours (.45/hr). I'm thinking I'm a pro and this won't be much longer, but here I am on my third day with a crystal clear pool, vacuumed twice a day, brushed 5 times a day, and it seems to be consuming more chlorine than at the beginning.

Yesterday (Saturday, day 3) I lost a ton of FC during the day, and even resorted to turning the SWG back on from 0% to 100% for part of the day. I got down to 0.0 CC during the middle of the day but FC was just being consumed even with the SWG on. Last night (night 3), I lost 8 FC (.76/hr) overnight, and again measured 0.0 CC a couple times during the day today with SWG on at 100% all day. All the while, during the day I've been adding a ton of chlorine despite the 0.0 CC measurements.

Am I doing this right?

My only thought is that maybe being a novice I have been doing CYA tests wrong, so late this afternoon I decided to say my CYA is actually 80 and I'm targeting 31 FC until this gets better. I also took my ladder out midday today (my steps are full width covered by vinyl). I've kept the cover off, ran the pump at 60 GPM 24/7, my pool gets full sun from 8-6:30, I've kept it clean and it's been visually clear for 2.5 days now (last night with the pool lights on the water was really clear). I guess I'm surprised that at 0 or near-0 CC readings and with the IC-40 running at 100% (PoolMath says it adds 0.3 FC/hr for my pool size) that I'm still consuming so much chlorine when all season I've been at about 45% during the day and been fine until a couple days ago.

Complicating matters is that I blew through my test supply, so I'll have to wait until the TFTestKits XL refill comes - I'm guessing Wednesday. I'll have to ration tests in the meantime and do my best to guess based on the last few days how much to add and when.

Thoughts? (Even if it's just "Stick with it, this is how it goes!")
 
You're on the right track. Getting that ladder out was good. :goodjob: Looks like you have Intellibrite lights, so this may not apply. But if you have a hollow niche behind anything, remove it as well. What about a main drain? Check under the cover if you have one.

CYA Testing:
Proper lighting is critical for the CYA test, so you want to test for CYA outside on a bright sunny day. Taylor recommends standing outside with your back to the sun and the view tube in the shade of your body. Use the mixing bottle to combine/gently mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then gently mix again. Then, while holding the skinny tube with the black dot at waist level, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. If it helps, pour a little, look away, then look back and pour some more. Some people like to squirt enough solution to go line-by-line for a better feel. Once it disappears, record the CYA reading. After the first test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate the CYA reading. If you are still questioning your own results, have a friend or two do the same test 2-3 times. Share your results only after everyone is done to see if you came up with the same average results.
Click to expand...
 
Texas Splash said:
You're on the right track. Getting that ladder out was good. :goodjob: Looks like you have Intellibrite lights, so this may not apply. But if you have a hollow niche behind anything, remove it as well. What about a main drain? Check under the cover if you have one.
Click to expand...
I think I remember when they installed the lights that they had these half spheres with a hole in the middle for wires but I’m not exactly sure what they look like behind there (I thought about the lights too and didn’t find any IntelliBrite-specific instructions anywhere.

Two main drains down in the deep end but I don’t think I could get down there and get them off reliably!
 
Just make sure to inspect every inch of that pool. Inside the skimmer, drains, etc. Hopefully that ladder removal was key. Dismantle it if you can to inspect and clean. Inject bleach in the tight areas with a turkey baster if you have to and rinse afterwards. Watch the filter pressure and backwash at 25% increase. Good luck!
 
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Guys I'm at a loss here. Today will be day 11 of this SLAM with crystal clear water and I just can't get this pool to stop drinking chlorine.

I pulled the ladder out last week, which did seem to slow down the FC consumption. Thursday we had a cloudy day and with the SWG on at 100% I actually saw my FC go up 4.5, which is what PoolMath would have predicted for my IC40 for that 10 hours or so. So I'm thinking I'm in good shape, this thing is about done, then the next morning I've I lost 3.5 FC and have 0.5 CC. Friday night I lost about 3.5, Saturday night I lost 5.5, last night I lost 4. Now, I did go swimming in it this weekend, and I do have little ones, but I did try to compensate with pouring extra chlorine in before and after. I'm going to put an embargo on the pool for a few days, much to the chagrin of the family, but I just don't know what else to do. My wife thinks I'm crazy brushing a spotless pool 3-4 times, vacuuming once and pouring gallons of chlorine in every day.

A couple of interim questions: what is the reason other tests aren't reliable during a SLAM? For CYA, is it a function of the clearness of the water interfering with the view of the dot? I tested CYA on the 12th with really clear water and got 60 so I'm wondering if one of the things I am dealing with is too much chlorine that is above my CYA SLAM level and in the full sun for 10 hours it's being eaten up. Doesn't explain my inability to pass a OCLT but I might save a few gallons if I target the 60 CYA SLAM level.

When I started the SLAM I knew from all my prior study that I needed to get the chlorine up to the SLAM level for my CYA so I just got bleach in ASAP and forgot I needed to adjust pH down to 7.2. It's been pretty stable all season - is it worth it now to adjust down based on prior measurement? I've had the pump running 24/7 for almost 2 weeks now so there has been more aeration, for what that's worth.
 
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The only test that is skewed a bit during the SLAM is the pH because an FC over 10 can start to make the pH climb. That's why we recommend lowering the pH before the SLAM. The other tests don't matter. The CYA number is very important as it is the foundation of what FC level you should be at for the SLAM. So if your CYA is 60 for example, your FC level should be 24. See FC/CYA Levels

As to why the continuous FC drop, I suspect there is something still hidden. There has to be. At night with no sunlight, only organic material will consume chlorine, so something is hidden. Maybe under those drain covers or behind a light if you have one that can be removed? Maybe it's time to re-check your CYA again?

CYA Testing:
Proper lighting is critical for the CYA test, so you want to test for CYA outside on a bright sunny day. Use the mixing bottle to gently mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then gently mix again. Recommend standing outside with your back to the sun and the view tube in the shade of your body at waist level. Then, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. Once it disappears, record the CYA reading. To help the eyes and prevent staring at the dot, some people find it better to pour & view in stages. Pour some solution into the viewing tube, look away, then look back again for the dot. Repeat as necessary until you feel the dot is gone. After the first CYA test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, gently shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate your own CYA reading. Finally, if you still doubt your own reading, have a friend do the test with you and compare results.
Click to expand...
 
Texas Splash said:
The only test that is skewed a bit during the SLAM is the pH because an FC over 10 can start to make the pH climb. That's why we recommend lowering the pH before the SLAM. The other tests don't matter. The CYA number is very important as it is the foundation of what FC level you should be at for the SLAM. So if your CYA is 60 for example, your FC level should be 24. See FC/CYA Levels

As to why the continuous FC drop, I suspect there is something still hidden. There has to be. At night with no sunlight, only organic material will consume chlorine, so something is hidden. Maybe under those drain covers or behind a light if you have one that can be removed? Maybe it's time to re-check your CYA again?
Click to expand...

All season I was at 70 CYA. Last week based on upthread back and forth I went out and tested it at 60. I just went back out and it is at 50. My water does drift up to the upper 80s/lower 90s and I've been SLAMing for a while, so I suppose that could explain some of it.

I mentioned I have little kids and we've had family with other little kids in there. I suppose it's possible that despite the swimmies, these kids keep putting number 1 and number 2 in there with the latter not being brought to my attention.

I pulled up the manual for the lights yesterday and it looks like the gasket is not reusable. I am a bit nervous messing with those units anyway given their price, but I may have to give in here soon, order a couple gaskets and do it. With respect to the drains in the deep end I'll have to search for some tips, as I have no idea how I'll get them out sans scuba gear.
 
What lights do you have?

The kids swimming will not have an effect on the OCLT. Unless they swim after you do the evening FC test.
 
I’m sorry I missed this one last time. You might be perfectly normal and having the high chlorine naturally diminish making it appear you have FC loss when you don’t. Check out what happened to NorcalX at the beginning of the season. Almost identical situation so it’s very possible.

Is SLAM inevitable? (YES...it was...5 Days of stress complete now)

Just had my first FC mishap where it dropped below expected and dipped below the minimum. Pool crystal clear entire time...but FC wouldn't rise. Here are my log notes PH is 7.5 CYA was increased from 60 to 80 during these notes Date FC 5/4 7.5 *Turned SWG off to check drift 5/6...
www.troublefreepool.com www.troublefreepool.com

TLDR. Sometimes the FC burns off much faster over 21. Let it drift down to normal and see if it holds.
 
mknauss said:
What lights do you have?

The kids swimming will not have an effect on the OCLT. Unless they swim after you do the evening FC test.
Click to expand...

IntelliBrite 5G. Thanks on the kids - I didn't know how long their effects would linger/how long it would take to clean up any potential artifacts they left in there. Yesterday they were all out around 6, I put in 3/4 of a gallon of chlorine and tested around 8:30, so it sounds like it should have been dealt with after that 2.5 hours.
 
Anything they deposit will be attacked by the chlorine immediately and only CC might hang around a short time.

I believe that light has an assembly that sets in the niche. You are saying the manual shows a gasket for the out side retaining ring?
 
Newdude said:
I’m sorry I missed this one last time. You might be perfectly normal and having the high chlorine naturally diminish making it appear you have FC loss when you don’t. Check out what happened to NorcalX at the beginning of the season. Almost identical situation so it’s very possible.

Is SLAM inevitable? (YES...it was...5 Days of stress complete now)

Just had my first FC mishap where it dropped below expected and dipped below the minimum. Pool crystal clear entire time...but FC wouldn't rise. Here are my log notes PH is 7.5 CYA was increased from 60 to 80 during these notes Date FC 5/4 7.5 *Turned SWG off to check drift 5/6...
www.troublefreepool.com www.troublefreepool.com

TLDR. Sometimes the FC burns off much faster over 21. Let it drift down to normal and see if it holds.
Click to expand...

I am glutton for punishment so I read the entire thing! This, coupled with my CYA test of 50 this morning and I just turned off my SWG to let this drift down to hopefully 20ish tonight. We'll see - thanks for posting this!
 
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REMOVING THE INTELLIBRITE 5G POOL LIGHT ASSEMBLY: Remove
the pilot screw at top of face ring, remove the light assembly from the niche.
Place the assembly on the deck.

You are not dis-assemblying the light fixture it self. You will not get to the point of needing a new gasket. That is only when replacing the light or board.
 
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