SLAM my pool for the first time

amart0319

Well-known member
Jul 15, 2024
63
Connecticut
Pool Size
8400
Surface
Vinyl
Chlorine
Liquid Chlorine
So after balancing my pool I started SLAM yesterday afternoon.

Attached picture is the color of the pool this morning at 6 AM

Day 1:
4pm added first dose of chlorine
2 hrs later 15 ppm
No chlorine add and 2 hrs later 8.5 ppm
Recommended Chlorine added 2 hrs later 7.5 chlorine added and bedtime.

Day 2:
(5.5 hrs) Water looks like picture attached. 6AM test 8.5 ppm chlorine added 8AM test 9 ppm will check again when home.

Is this normal so far? Water still being green? Is the process as expected?
 

Attachments

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It is normal. With it that green, I would recommend that you test and replace FC every 2 hours.
Watch your filter pressures. They should be rising fast. Clean your cartridges, not clean pressure, when pressure rises 25% clean again. With it that green, you may be cleaning filters a lot.
 
That green is going to be a slow go if you need to work during the day. We do what we can. Do every two hours when you are home, even late into the night..,
 
A bit hard to follow what your readings were vs how much you added. Nor did you note what your CYA level was...
But obviously with that green, you will need lots of Cl, very often, for the fastest results. If you can't babysit it by testing and adding every couple of hours, then it will just take longer. Some here relate it being a couple of weeks before all done. No overnight cures.
As noted, especially at the beginning, your filter will plug up pretty fast. If you have a way to bypass it, that would be better if you have to be gone (at work, etc.). That will mean more accumulating on the bottom, and therefore more vacuuming when you get home.
 
Thank you for this. I am actually working from home so I am going to stay on this every two hours today and clean the filter as much as possible. Sorry that was so hard to follow.
Question for ya, tested my cya just now its definitely less than 30. Should add some stabilizer even if im already in my SLAM process? Pool chlorine in about 15 minutes ago. Also, how do I know how much to put in?
 
Question for ya, tested my cya just now its definitely less than 30. Should add some stabilizer even if im already in my SLAM process? Pool chlorine in about 15 minutes ago. Also, how do I know how much to put in?
Add 10ppm of CYA.
Use pool math to calculate additions...Link-->PoolMath
 
Put it in a sock, or old t-shirt, and suspend that in the pool. Near a jet if you can. Every few hours knead the sock a lot to squeeze out what gets dissolved. CYA is slow to dissolve, and if just dumped in can make a pile that is not good in concentration for your liner. It may take a couple of days of circulation after to get a stable new CYA reading, so don't start dumping more in until you are sure. At the same time, boost your FC SLAM level to what you hope will be your new CYA amount - and then adjust later after verifying.
 

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No more than every two hours, and at least 3-4x a day. If you can do it every 2 hours, SLAM will go faster.
So for the last 2 days ive been doing every 2 hours and brushing and cleaning filter and I see no difference at all. Not even a bit. There has been barely any sun for the last 24 hours so the chlorine should be doing its job no? I find it odd that i’m start of day 3 and overnight after adding amount of chlorine to get back to 10 (slam fc number) before bed no sun out at all even cooler out then usual and I only lost .5 chlorine overnight. No visible changes what so ever. Not even the slightest. Also my filter cartridge has been barely dirty when I clean it. Doesn’t seem right.
 
Stay on it and keep the FC in the proper slam range for your cya level. Even a little higher is ok as the algae will reduce it in short order.
There is a war going on in your pool. The FC needs to overcome and kill the algae and the algae is trying to grow when the FC dips. Keep the FC up to slam levels and the filter clean and you will win. Also brushing helps a lot.
 
Stay on it and keep the FC in the proper slam range for your cya level. Even a little higher is ok as the algae will reduce it in short order.
There is a war going on in your pool. The FC needs to overcome and kill the algae and the algae is trying to grow when the FC dips. Keep the FC up to slam levels and the filter clean and you will win. Also brushing helps a lot.
Thank you for your positive feedback. Very easy to lose faith in the process. I need to be patient and stay the course.

The pool math app is telling me my SLAM number is 10 according to what? Does go off the gallons in the pool?
 
It is based on this chart, found in the recommended levels on this site.
You said before that your CYA is 30. So your SLAM level should be 12, not 10. If you've added CYA as you said you might, the new target will be higher. If you just recently added the CYA (within a day), the addition may not fully test out - so just use what you hoped your new level was going to be. In a day or more after the add, the tested level will stabilize, and you can use that new FC level for the SLAM going forward. If between two readings for CYA, always round up to the higher "10's" unit. Using a slightly lower target, as you appear to have done, isn't a big deal - the SLAM will just be a small amount slower than it might otherwise have been.

CYA Chart.jpg
 
Post another picture or two. If you have a ladder or similar, include that in a picture - it helps in judging the current visible depth. Are you able to see if there are any piles of dirt on the bottom?
BTW - it is the UV from the sun that causes Cl to be ineffective. So just as you can get sunburnt on a cloudy day, so can your pool.

What is your water source? Well? City water? The initial picture clearly looks to be algae, but do you have a high iron content in your water supply?
 
Post another picture or two. If you have a ladder or similar, include that in a picture - it helps in judging the current visible depth. Are you able to see if there are any piles of dirt on the bottom?
BTW - it is the UV from the sun that causes Cl to be ineffective. So just as you can get sunburnt on a cloudy day, so can your pool.

What is your water source? Well? City water? The initial picture clearly looks to be algae, but do you have a high iron content in your water supply?
Thank you for the chart. I about half cup of stabilizer this morning so my slam fc might change in a couple days but i’ll test when i get home anyway. My pool was fresh filled this yr with city water this year. I can see through the water to tell if there is debris. I took out my latter in day 1 of slam. I will send a better picture later when i’m home. How can I find out my iron content?
 

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