1. SLAM--keep going?

So I started SLAM yesterday morning. Water has always been clear, though yesterday there was mustard algae buildup on the walls when I vacuumed. FC was at 0 for at least a week.

Based on your help, I was told my pool needed 20 gallons of bleach based on its size. According to the chart, my FC shock goal is 12.

I put in only 8 gallons and

FC 34 at 10:30
FC 21 at 1pm
FC 15 and CC 1.5 at 2:30
FC 11 and CC 1.5 at 8:30.

This morning: FC 4.5 and 1.5 CC.

I know the pool didn't pass the OCLT and the CC is still high, but do I need to keep SLAMing this morning? If so, how many gallons should I add? The extreme FC I got yesterday morning is making me hesitate.

2. Re: SLAM--keep going?

Yes, you will need to continue your SLAM. Remember, a TFP SLAM is not like a common pool store "shock" or short-term procedure. You'll want to maintain that elevated FC level until you pass all 3 SLAM criteria. To determine how much bleach to add back to the water to increase your FC level, simply use the Poolmath calculator and it will show you exactly how much to add. If you have a problem using the calculator (link below) let us know.

3. Re: SLAM--keep going?

Welcome to the Forum. I am assuming you are testing with a recommended test kit. If so, this is a fairly simple process as the SLAM takes a few days and could take up to a few weeks (all depends on the condition of the pool). We here at TFP love to help, although you will need to familiarize yourself with Pool Math. Plug in the amount of gallons in the calculator and % of bleach and you will know how much to add each and every day (all depends on how often you can test).

Please post up a full set of results and we will go from there. Your shock level (SLAM) is based on your CYA. You will need to add enough bleach to bring your pool to shock level and then "Maintain" the level as much as possible throughout the day. If you maintain the level daily (add once a day), the process will take a little longer. Based on your first post, it appears you will need to add at least twice daily to keep the level at shock level.

Please provide results (full set) and then follow the instructions carefully during the SLAM. You will need to brush the walls and floors regularly and backwash when necessary, sometimes overlooked. Please use pool math to check the size of your pool. I have found that most people believe there pool is of more volume and add more chemicals than necessary, therefore causing even more problems.

4. Re: SLAM--keep going?

Looks like somehow you miscalculated chlorine. Number I get is 480 oz of 8.25%. YES you need to continue SLAM. You must keep chlorine at 12 PPM. Need to add chlorine as necessary (to start, if possible, check numbers and add as need every two hours. If this is not workable, at least 4 x a day.

At 4.5 FC you need to add 300 oz (3 gal). With the chlorine loss you had overnite, you are going to be SLAMming for a couple of days. Keep brushing, filter running 24 hours, backwash as needed (probably 1 x day). Get another 10-15 gallons of bleach, assuming you are using 8.25%?

Any thoughts or questions, ask. BTW, what test kit are you using?

5. Re: SLAM--keep going?

So I started SLAM yesterday morning. Water has always been clear, though yesterday there was mustard algae buildup on the walls when I vacuumed. FC was at 0 for at least a week.

Based on your help, I was told my pool needed 20 gallons of bleach based on its size. According to the chart, my FC shock goal is 12.

I put in only 8 gallons and

FC 34 at 10:30
FC 21 at 1pm
FC 15 and CC 1.5 at 2:30
FC 11 and CC 1.5 at 8:30.

This morning: FC 4.5 and 1.5 CC.

I know the pool didn't pass the OCLT and the CC is still high, but do I need to keep SLAMing this morning? If so, how many gallons should I add? The extreme FC I got yesterday morning is making me hesitate.
According to Pool Math, in a 27K gallon pool, 8 gallons (1024oz) of 8.25% chlorine (laundry bleach) would add 25ppm FC, 8 gallons of 10% chlorine would add 30ppm, 8 gallons of 12.5% would add 37ppm. What strength is your chlorine?

Please let us know where you got the 20 gallon recommendation from as that is ridiculously incorrect. 20 gallons of 8.25% would add 63ppm to your size pool.

Dom

6. Re: SLAM--keep going?

I'm using the TFTest kit 100.

As for the 20 gal suggestion from max2k:
"Is 50% drain refill an option? This is to bring your CYA down to make your life easier later.

If not- add MA to bring pH down to 7.2 and stock up on bleach to perform SLAM, at least 20 gallons at your current CYA level. Make sure your filter/pump in good working order."

At least I'm set on bleach now (I think) for however long it takes to slam.

I've bought Walmart brand bleach which is 10%. Does that make a difference?

I added 3 gal of bleach and will test in a bit to see where that puts my numbers. I just went to brush, and clouds of yellow algae came up. Going to vacuum instead. Unfortunately, our pool only has two jet returns and a filter for a smaller size pool, which I don't think are enough to circulate water/waste well for the volume of our pool.

Thanks again for all your help! You guys are amazing!

7. Re: SLAM--keep going?

I'm using the TFTest kit 100.

As for the 20 gal suggestion from max2k:
"Is 50% drain refill an option? This is to bring your CYA down to make your life easier later.

If not- add MA to bring pH down to 7.2 and stock up on bleach to perform SLAM, at least 20 gallons at your current CYA level. Make sure your filter/pump in good working order."

At least I'm set on bleach now (I think) for however long it takes to slam.

I've bought Walmart brand bleach which is 10%. Does that make a difference?

I added 3 gal of bleach and will test in a bit to see where that puts my numbers. I just went to brush, and clouds of yellow algae came up. Going to vacuum instead. Unfortunately, our pool only has two jet returns and a filter for a smaller size pool, which I don't think are enough to circulate water/waste well for the volume of our pool.

Thanks again for all your help! You guys are amazing!
It looks like you mis-read that suggestion.....

Originally Posted by max2k
......stock up on bleach to perform SLAM, at least 20 gallons at your current CYA level.
max2k did not tell you to add 20 gallons of bleach to your pool, he suggested that you purchase 20 gallons to use during the duration of your SLAM.

FYI- At the bottom of the pool math page is a section titled "effects of adding chemicals". Once you enter your pool volume at the top of the page you can enter how much and what chemical to see what effect it will have on your pool before you add that chemical.

Dom

8. Re: SLAM--keep going?

I've been using the PoolMath, but just now saw the calc at the bottom. Easier for me than the FC/CYA chart.

Thanks, Dom!

9. Re: SLAM--keep going?

I've been using the PoolMath, but just now saw the calc at the bottom. Easier for me than the FC/CYA chart.

Thanks, Dom!
You still need the FC/CYA chart to determine proper FC level.

Dom

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