Why am I losing this SLAM?

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S

SW Pool Owner

Well-known member
Jun 24, 2022
94
Long Island, New York
Nearly a month long SLAM now. Ended the first one I guess prematurely, because within a week I had light brushes of algae again. Last 3 days the pool finally turned 80% clear and no more brushing up green algae, only dead clouds. I paused my 2nd SLAM because I had friends + kids coming over and I wanted to use the pool.

The chlorine was at 12 when we went in with CYA of 50. I turned on the pool heater to 90 degrees. It seems like during using the pool the water got cloudy quick. I even added shock right after we swam to bring the FC up. Today I check on the pool and over the dead algae I didn't brush yesterday is green algae. I'm brushing and I'm seeing thick clouds of green being blown up.

I'm going to keep SLAMing this time around, but I'm wondering if anyone has encountered anything similar or has advice to share. It seems ridiculous to me that just because I didn't bring to shock level for a day I'm back to where I was a week ago?
 
SW Pool Owner said:
Nearly a month long SLAM now. Ended the first one I guess prematurely, because within a week I had light brushes of algae again. Last 3 days the pool finally turned 80% clear and no more brushing up green algae, only dead clouds. I paused my 2nd SLAM because I had friends + kids coming over and I wanted to use the pool.

The chlorine was at 12 when we went in with CYA of 50. I turned on the pool heater to 90 degrees. It seems like during using the pool the water got cloudy quick. I even added shock right after we swam to bring the FC up. Today I check on the pool and over the dead algae I didn't brush yesterday is green algae. I'm brushing and I'm seeing thick clouds of green being blown up.

I'm going to keep SLAMing this time around, but I'm wondering if anyone has encountered anything similar or has advice to share. It seems ridiculous to me that just because I didn't bring to shock level for a day I'm back to where I was a week ago?
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Post some test results from your Taylor kit? Pictures of the water? You can swim in the pool during a SLAM.
 
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As you continue the SLAM, you also need to look where algae could be hiding, skimmer boxes, skimmer weirs, light niches, drain covers, any other features with surfaces which may not be getting brushed well. Unfortunately it takes more chlorine and work to rid a pool of algae, than it does to prevent algae.
 
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I'm looking for visible green surfaces right, not an invisible layer of algae? Because I've scrubbed everywhere I Can visibly see and there is nowhere left. My light fixtures are loose so water flows behind, I guess I need to make the effort and unscrew and look behind it to see anymore, but from what I saw there's nothing around the outer-inner area I could see
 
If water can go there algae can grow there
Scrub everything not just green stuff.
*Check & scrub every nook & cranny where algae may hide (light niches, steps, drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, etc.)
*If water can go there, algae can thrive there.
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine) 👈
*Backwash/clean filter when pressure rises 25%over clean pressure.
As mentioned it is safe to swim with fc up to slam level for your cya.

Use some DE in your sand filter to help catch the finer dead stuff.
www.google.com

Add DE to a Sand Filter

A clean pool filter will increase the efficiency of your pool! ... your filter are to backwash it, clean the manifolds and grids, and add new DE.
www.google.com www.google.com
You may also need to do a deep clean of your sand it’s something that should be done every season or two anyway

Deep Cleaning a Sand Filter

This post will walk you through the anatomy of a sand filter, and then provide a video at the end for how to deep clean your sand filter. The filter used in the photos and videos is a Hayward S180T top mount sand filter. The images are of a similar filter. Obviously not all filters are...
www.google.com www.google.com
 
The simple answer is lack of chlorine.

With a crystal clear pool with no algae present, your FC level should be 6-8 at 50 CYA.
Your pool has algae and is not crystal clear, so the FC should be 20.

You posted that it was 12 and had people swimming which also increases your FC demand. Unfortunately the existing algae + the cooties from the people swimming was more demand than your chlorine level and the algae multiplied.

Not the end of the world and glad you were able to enjoy your pool. Now take a deep breath and get it back to SLAM level.
 
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Ok so FC is sitting at 21 and I brushed lots of dead algae, there's a lot more algae on the shallow side than the deep side when I brush. The stairs entering the pool and the 3'8 section when I brush I see lots of dead algae being brushed to the point where the water being brushed up is thick and cloudy whereas at the deeper end of the pool it's just clouds of dust being blown up barely noticeable.

I'm not sure if that's expected or points to a circulation issue
 
SW Pool Owner said:
Ok so FC is sitting at 21 and I brushed lots of dead algae, there's a lot more algae on the shallow side than the deep side when I brush. The stairs entering the pool and the 3'8 section when I brush I see lots of dead algae being brushed to the point where the water being brushed up is thick and cloudy whereas at the deeper end of the pool it's just clouds of dust being blown up barely noticeable.

I'm not sure if that's expected or points to a circulation issue
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It’s a common part of the SLAM. Dead algae means there’s a battle going on which is a good thing in this case.
 
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Good job brushing and getting it back to SLAM level. Now it is a waiting game for the chlorine to kill alive algae and the filter to filter out the dead algae so the more times a day you brush and add chlorine the better.

Do you have a cleaner too that can help vacuum up the dead stuff too? If it has a fine mesh/filter on it that will help trap some of the dead algae.
 
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Yup running cleaner once a day, brushing 1 - 2 times a day. I just brushed again now maybe 4 hours after brushing and I'm brushing up thick clouds from the stair again. Sticking through it and I'm waiting until we're crystal clear and dead algae, and then I wonder what I do at that point to ensure this doesnt grow back in 2 - 3 weeks just like last time I did SLAM.
 
drsipe said:
Behind the light is a big one, a lot of people see a cloud of algae when the light is removed. I pull the light at least once a year to clean behind it.
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Im having a hard time understanding how to remove / re-insert the pool light. I have one where it's screwed in but wobbles around and can be pulled up, because there's only one screw. I have another one where the screw won't thread into the plastic frame in the liner / pool wall
 
So sorry to hear this is taking so long. TFP methods work based on data and I can't see any of yours. Please post a record of your FC PH and CYA test results. Without any data I'll just take a wild guess that you are missing the "M" in SLAM. This always extends SLAM duration because it's a SLA not a SLAM. SLAM level must me Maintained for this to work. You've got a big pool and I know it's costly to get the FC level up. I would check the FC level at least 2-3 times a day for a couple days. Adjust your FC level to bring it up to SLAM level (not over that level) and I bet you start to see BIG improvement.

I hope this is helpful.

Chris
 
FC - 24
pH - 7.4 pre-slam
CYA - 50 pre-slam
Total Alkalinity - 70 pre-slam
Calcium hardness - I can't seem to find my last log of this, but I remember it was a very much in the range number like 100?

I have 3 returns evenly spaced on the right 36' side, with 3 skimmers directly across, 1 skimmer being in the stairs area. I have one waterfall in the direct center of the 40' side, this waterfall is rarely turned on except for a few hours when I SLAM, because there is a large leak when I run the waterfall sometimes. It does not always leak when run, it seems to depend on factors I haven't been able to figure out.
1690828959272.jpeg
 
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You would only unscrew the screws on the metal ring to remove the light from the niche.
Do not unscrew any of the ones on the white ring - they hold the niche in the wall.
That box is the junction box for the pool light.
Be sure the power for the light is turned off at the source (breaker & switch) before removing.
Btw- your water is looking very clear!
 
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SW Pool Owner said:
FC - 24
pH - 7.4 pre-slam
CYA - 50 pre-slam
Total Alkalinity - 70 pre-slam
Calcium hardness - I can't seem to find my last log of this, but I remember it was a very much in the range number like 100?
Click to expand...
SW,
That's one data point. Do you have data for several tests in a row? Reason I ask is if they are dropping well below SLAM before you add more liquid chlorine the algae has time to "recover". If your FC level is returned to SLAM level each day you will start to see big improvement over time. But if you have a really bad case I've seen many cases where it helps to shorten the SLAM if you test and re-establish SLAM level 2 or 3 times per day for a couple days. After that, daily should be sufficient. This will seem like you're using a LOT of liquid and you are but if you think about how much is used by extending the SLAM into weeks longer it actually reduces total liquid chlorine needed.

I hope this helps.

Chris
 
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SW Pool Owner said:
So brushed three times, 4 and 8 hours apart respectively. Each time clouds of algae, way thicker on the shallower side but it is gradually getting better. Holding patience for sure.

FC seems to dip to 16-17 always and I top off to 22
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That's a lot of work! How many days have you been doing this?
 

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