FC low after attempt at SLAM

[barbc2000]

Basically, test, then add back to SLAM target. Your target with a CYA of 60 is 24ppm per the FC/CYA Levels. So if you test at 0ppm, you put 0 in Pool Math, put 24 for the target, put in the strength of the chlorine you're using, and it will tell you how much to add for your volume of pool. In an hour, if you test and it's 21ppm, you put 21ppm in the current, 24 for target, and it will tell you how much to add to get 3ppm more added. Repeat as often as you can, brush and vacuum often. Test and add at least 2-3 times a day, up to once an hour. The more you can do it the faster it will go. Taking a break to do things like sleep is fine - you'll just get back to it when you get up.

If your water is already still clear with no signs of algae, then really you're just looking to see if it drops overnight, between when you go to bed and when you wake up. If it doesn't, then you're done and you can let the FC drift back down to about 7-9. Test daily to make sure it stays in that area. Don't ever let it get below 5, because that's when you can get algae growing.

Let us know how it goes!

I have been using the PoolMath app but it never raised the FC until now. The app recommended 6 gallons to go from 0.5 to 24. I added and tested one hour later. FC 14.5!!! Put that number in the app and now I added 2.5 more gallons. I'll test in another hour.

Once I hit my target of 24, do I keep testing hourly? Do I wait until tomorrow morning?
When do I turn the SWG back on?
When is the pH test reliable again? (i'm sure it's low now)
What do I use to raise the pH?

Thank you!

 

[IceShadow]

Once I hit my target of 24, do I keep testing hourly? Do I wait until tomorrow morning?

You keep testing hourly. Your FC will drop, some due to the sun, but more due to whatever is in your water that's eating it up. Keep testing and adding more to get back to 24.

When do I turn the SWG back on?

Once the SLAM is complete and you no longer lose more than 1ppm of FC between dusk and before dawn (overnight). Before then it's a waste as it's really not going to put out enough FC that you need - the liquid chlorine is the way to go.

When is the pH test reliable again? (i'm sure it's low now)
What do I use to raise the pH?

Don't worry about the pH mid-slam. The test won't work if the FC is above 10 anyway. Let's get rid of whatever is in the pool and then when your FC goes back down after we're done, you can adjust the pH.

Thank you!

No problem Can you share some pictures of the pool? It'd be good to see how it's doing - sometimes a photo is worth a thousand words after all

 

[barbc2000]

You keep testing hourly. Your FC will drop, some due to the sun, but more due to whatever is in your water that's eating it up. Keep testing and adding more to get back to 24.



Once the SLAM is complete and you no longer lose more than 1ppm of FC between dusk and before dawn (overnight). Before then it's a waste as it's really not going to put out enough FC that you need - the liquid chlorine is the way to go.


Don't worry about the pH mid-slam. The test won't work if the FC is above 10 anyway. Let's get rid of whatever is in the pool and then when your FC goes back down after we're done, you can adjust the pH.



No problem Can you share some pictures of the pool? It'd be good to see how it's doing - sometimes a photo is worth a thousand words after all

here are some pictures.

You can see my empty chlorine jugs

 

[IceShadow]

Looks pretty good let’s see if the chlorine level drops between dusk and tomorrow morning before dawn.

 

[barbc2000]

Looks pretty good let’s see if the chlorine level drops between dusk and tomorrow morning before dawn.

Last night FC 26. This morning 21. It did rain last night. How much does rain affect the FC level?

 

[IceShadow]

Last night FC 26. This morning 21. It did rain last night. How much does rain affect the FC level?

It doesn’t unless it washes a bunch of stuff from your deck into your pool. So, something is happening. Time to hunt for hidden algae. Can you take photos of anything in your pool? Ladders, skimmers, drains, lights, returns, etc. Any auto fill?

 

[barbc2000]

It doesn’t unless it washes a bunch of stuff from your deck into your pool. So, something is happening. Time to hunt for hidden algae. Can you take photos of anything in your pool? Ladders, skimmers, drains, lights, returns, etc. Any auto fill?

Here are today's numbers. SLAM level is 24. Overcast and rainy all day.

5:15am - 21 - + 3 quarts LC
9:35am - 25.5
11:25am - 26
1:35pm - 22.5 - +1.5 quarts LC
3:15pm - 24
5:15pm - 25.5

So I think I'm almost done. I've only added 4.5 quarts today and have been above 24 most of the day.

 

[stma111]

Hi Folks…. Although I’m new to this forum, I’m a former veteran at PoolDoc and Ben Powell.
Without getting into all the details which I can provide later, is it safe to swim in the same water condition that BarbC reported at the beginning of the string..?

 

[IceShadow]

Hi Folks…. Although I’m new to this forum, I’m a former veteran at PoolDoc and Ben Powell.
Without getting into all the details which I can provide later, is it safe to swim in the same water condition that BarbC reported at the beginning of the string..?

Without knowing what was in the pool, it’s hard to say. I wouldn’t want people swimming in an under-chlorinated pool, even if clear. It could have bacteria, etc. that you don’t know about.

 

[tim5055]

Hi Folks…. Although I’m new to this forum, I’m a former veteran at PoolDoc and Ben Powell.
Without getting into all the details which I can provide later, is it safe to swim in the same water condition that BarbC reported at the beginning of the string..?

Until I knew what was causing the chlorine demand I probably wouldn't swim in it. As @IceShadow indicates, clear does not = sanitary.

On another note, many of us oldtimers started on Ben's forum. There was a lot of knowledge, but it seems ot have dropped off over the years.

 

[barbc2000]

So the SLAM is done! Started on Friday, 5/27.

Husband and brother said I was crazy on 5/28. Pool water was crystal clear. Why was I still doing this and when could we start the SWG. I explained something was eating the chlorine (OCLT 5ppm)and we needed to fix that first. Suggested the pool light might be the source.

5/29 OCLT 3.5ppm

Late afternoon on 5/29 pool light finally comes out and lo and behold lots of algae! We vacuumed it out.

5/30 OCLT 2ppm. FC 21. Hot, sunny day and had a cookout. Added no chlorine. FC15 15hrs later.

5/31 OCLT 1ppm. CC 0.5 and crystal clear!

So do I let the FC drift down to 6-8, then start the SWG?
I'm sure the pH will be a problem and you said it's not accurate when FC > 10, so I'll wait to test that.

Thanks again! I'm so happy to be algae free!

 

[tim5055]

Husband and brother said I was crazy on 5/28.

Remember the appropriate "I told you so"......

Good Job!!

 

[IceShadow]

Test your salt, make sure it's in range, start up the SWCG when your FC is down where it needs to be. Might be a good idea to bump your CYA up to recommended areas too.