Ending a SLAM?

Beachkimball

Member
Jul 2, 2019
22
San Antonio, TX
Hi all. I have a 20,000 gallon chlorine pool with a sand filter. The last few weeks I was getting cloudy and green, and I started a SLAM. Unfortunately, my FAS-DPT kit is still in the mail, but I have been measuring chlorine with other kits and the color is burnt orange, so pretty high. Filter has been on 24 hours a day for almost a week now. 109719

Anyway, the green color is gone, I’m not seeing any algae/green when I scrub the steps/walls, and the water is much clearer, but still not clear. I have a few of those kids diving toys at the bottom of the deep end, and I can see them again, but not clearly. So here is my question: If the water is blue but still slightly cloudy, should I keep adding chlorine (have been using liquid bleach), or just let it clear up?

Thanks in advance for any advice while I await my real kit in the mail.

Brett
 
Welcome to the forum!
There are three criteria to a successful SLAM Process. They are described in the linked article. The first is crystal clear water.
I would suggest backing off on the chlorine additions until your proper test kit arrives. You do not state what your CYA is, but with too high FC levels you can be damaging your liner, if you have one.
Can you fill out your signature?
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
 
Thanks! CYA is always high in the three months I’ve owned this house / had this pool. It is 100 right now, and that’s after draining and refilling about 20% last week before starting the SLAM. The guys at the local pool store say that’s just how this city is, with really hard water, and that it’s not a problem. Everything I read online says they are wrong, but I have to figure even with chemistry being chemistry, there has to be a local component to this, right?

Thanks for the help. Will hold tight until the kit arrives. Appreciate what you guys do here.
 
CYA is added via pool chemicals. And 100 is the top of the test limit. Could be higher.
 
The water is definitely hard also, but our CYA based on the Aquatest test strips is right about 100. It’s been over 100 for the three months that I’ve had the pool, and the last two weeks are the only problem I’ve had with algae.
 
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Update: Went to my pool store and they ran tests for me while I await my FAS kit in the mail. Results below. They advised me to add clarifier, and keep Chlorine between 7-10, but that I didn’t need to SLAM further. Pic attached of current water color/clarity.
FC: 10
TAC: 10
PH: 8.0 (I added 1/2 gallon of 31% acid this morning about 4 hours before taking sample, so they said to wait before I add more)
TA: 90
CYA: 100
CH: 20
TDS: 1100
Phosphates: 200
 

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While you are waiting on your test kit, add 5 ppm FC worth of liquid chlorine / plain bleach to your pool each evening with the pump running.
 
Pool store testing is worthless and their advice is worth even less than that. Please tell me you didn't follow their advice. For instance, you can't get a good pH reading when the FC is that high, so your addition of acid may have actually been unnecessary or even counter-productive. Pool store employees should know that, but apparently they don't. Professionals indeed ? I see their chlorine test also maxes out at 10, so your kit will actually be far superior to theirs.

The bottom line is that you have not been "SLAMing" your pool. To SLAM is to follow the SLAM Process which requires tests that you don't have yet. You have made admirable progress with what you have, but you really need to step back for a moment and wait for your kit to arrive so you have good solid numbers with which to move forward with. Being patient is the most difficult part of this process, but it is also one of the most important parts. Impatience leads to shortcut attempts (or worse, taking pool store advice ? ) and often ends up costing far more in both money and time in the end.
 

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When I moved in to my new house, my pool had a CYA of 120 and I had algae problems regardless of the FC levels. I drained the pool twice to get the CYA down to 40 and switched from expensive pool store trichlor to pool bleach. Never had a problem since. You may want to drain 1/2 your pool to get your CYA down.
 
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