First Time SLAM

[bgoz98]

After a month or so of normal water conditions, I woke up to a cloudy pool yesterday and zero FC (also zero CC). Added liquid chlorine and turned salt cell up to 100% but was still losing ground. Failed OCLT last night (ugh). Guessing next step is to SLAM. CYA is between 60 and 70. Which do I use for SLAM FC level? Also, please confirm SLAM is the next logical step here.

Side note: We are supposed to be having a swim party for my son’s bday this evening. Is it safe to swim if I just add some liquid chlorine to get it up to 5-7 FC and then start SLAM after? Definitely don’t want anyone going home with any ill effects.

 

[Texas Splash]

Which do I use for SLAM FC level?

Use 70 as your SLAM guide when you go to the FC/CYA Levels. That would require an FC SLAM level of "28". Make sure you lower the pH to about 7.2 before increasing the FC.

 

[Texas Splash]

As for the swim party, it is safe for swimmers to be in the water as long as you don't exceed the FC SLAM level, in your case 28. But if you increase the FC level this morning and wish to allow it to fall a little before the party to say 20 for example, thats fine. As soon as the party if over, crank it back up and maintain it until you pass all 3 SLAM criteria on the SLAM Process. Good luck!

 

[bgoz98]

As for the swim party, it is safe for swimmers to be in the water as long as you don't exceed the FC SLAM level, in your case 28. But if you increase the FC level this morning and wish to allow it to fall a little before the party to say 20 for example, thats fine. As soon as the party if over, crank it back up and maintain it until you pass all 3 SLAM criteria on the SLAM Process. Good luck!

Thank you. I just tested to confirm CYA and it is actually between 50-60, so I assume I will use 60 or FC of 24. I went ahead and edited my first post to avoid confusion. So just to confirm, it is better for them to swim at slam levels of FC versus maintaining a normal level of FC knowing that there is something/algae in the water?

 

[Texas Splash]

CYA and it is actually between 50-60, so I assume I will use 60 or FC of 24

Correct. You can start the SLAM this morning if you wish, or wait. Swimmers won't know the difference either way. So you can start to boost the FC this morning to get a jump on the SLAM, then skip adding chlorine in the afternoon or a few hours before the swim party. Or just increase the FC to 16-20 today if it feels more comfortable for you with people coming over.

In the end, as long as the FC doesn't exceed 24 it's safe.

 

[bgoz98]

Correct. You can start the SLAM this morning if you wish, or wait. Swimmers won't know the difference either way. So you can start to boost the FC this morning to get a jump on the SLAM, then skip adding chlorine in the afternoon or a few hours before the swim party. Or just increase the FC to 16-20 today if it feels more comfortable for you with people coming over.

In the end, as long as the FC doesn't exceed 24 it's safe.

One more question: For my DE filter, I understand frequent backwashing may be necessary during the SLAM process (based on increased pressure on gauge). After backwashing to clear water, I will need to add 80% of recommended each time after? At any point in this process, do I need to perform a full filter tear-down/clean? I did it a month ago when I opened the pool. Thanks again for all of the help!

 

[Texas Splash]

At any point in this process, do I need to perform a full filter tear-down/clean?

Right now I'm going to say no. That could change later if for some reason backwashing doesn't seem to lower the filter pressure, but for now you should be fine.

 

[bgoz98]

Right now I'm going to say no. That could change later if for some reason backwashing doesn't seem to lower the filter pressure, but for now you should be fine.

Is the standard practice to shut off the salt cell entirely (maintaining SLAM level with liquid chlorine) for the entire process? And do you also perform a OCLT every night or does that start after 24, 48, etc hours of holding SLAM level?

 

[Texas Splash]

Yes, SWG off and use liquid chlorine. Hold off on the Overnight Chlorine Loss Test until the water is crystal clear and it's basically your final slam item to finish. Good luck.

 

[bgoz98]

Yes, SWG off and use liquid chlorine. Hold off on the Overnight Chlorine Loss Test until the water is crystal clear and it's basically your final slam item to finish. Good luck.

Thanks. Should I leave the cover closed or open during slam (when I’m not scrubbing, adding chlorine, etc?

 

[Texas Splash]

Should I leave the cover closed or open during slam

Closed for part of the day is fine, but allow the sun to hit the water for a few hours each day to allow proper oxidation to the combined chlorines. Also be mindful of the bottom side of the cover as they can trap moisture and be a breeding ground for organics.

 

[bgoz98]

Closed for part of the day is fine, but allow the sun to hit the water for a few hours each day to allow proper oxidation to the combined chlorines. Also be mindful of the bottom side of the cover as they can trap moisture and be a breeding ground for organics.

So this reply got me thinking... Is it possible for the only growth/organics to be on the underside of the auto cover? I have been scrubbing per the guidelines everywhere that I can, but scrubbing the underside of the cover would be a major challenge (especially in the end towards the reel). Is that a necessity or does its contact with the SLAM'd water overnight kill off everything?

The reason I ask is that my water is crystal clear (was cloudy for a day when I started), my CC has never been more than .5 (zero in the last several tests during SLAM), but I keep losing FC (even at night). We went on vacation for 2 weeks and left the pool cover closed. I made sure the SWG was turned up a little and came back to clear water with an initial test of FC 10, CC 0. A week later, I open it up one morning to FC 0 and cloudy water. That same day, I noticed my filter pressure up 50% or so from normal. It stayed that way until yesterday and then dropped back down to normal (and has been there since). I didn't backwash or anything.

 

[Texas Splash]

The cover can certainly be a culprit. It has been for others. If it is, or is the ONLY one, we can't be sure. That's where you have to do a process of elimination. For example, do you have a large light with a niche behind it? Hollow steps or ladder in the water? Anything else touching the water that could hide algae? For some owners it's even under the drain covers. Once all of those are eliminated, about the only thing left is the cover. You could experiment by leaving the cover off for a day or two to compare.

 

[bgoz98]

The cover can certainly be a culprit. It has been for others. If it is, or is the ONLY one, we can't be sure. That's where you have to do a process of elimination. For example, do you have a large light with a niche behind it? Hollow steps or ladder in the water? Anything else touching the water that could hide algae? For some owners it's even under the drain covers. Once all of those are eliminated, about the only thing left is the cover. You could experiment by leaving the cover off for a day or two to compare.

Thanks. We have a light and of course the jets/returns. No drain or hollow stairs. I will leave the cover off and test it out. Any ideas on how to clean it if it ends up being the only culprit?

 

[Texas Splash]

Any ideas on how to clean it if it ends up being the only culprit?

I guess that would depend on how accessible it is, or how practicable it is to remove it. A big pain I would assume. Ideally, pulling it back to an area that would allow you to lay it out flat and apply a chlorine-water moisture, then brush it really well. Finally, allow the underside to be exposed to direct sunlight to help dry it out thoroughly. Easy for me to say though.

 

[bgoz98]

I guess that would depend on how accessible it is, or how practicable it is to remove it. A big pain I would assume. Ideally, pulling it back to an area that would allow you to lay it out flat and apply a chlorine-water moisture, then brush it really well. Finally, allow the underside to be exposed to direct sunlight to help dry it out thoroughly. Easy for me to say though.

Yeah, I am going to have to do some thinking on that. It is on a motorized reel so disassembly is quite a project. Do you believe the organism would be vis on the underside? Just thinking I could confirm before disassembling.

 

[Texas Splash]

Do you believe the organism would be vis on the underside?

Maybe. Some owners have been able to see growth once they made it a point to inspect carefully. One of those "out of sight - out of mind" things that sometimes catches up to a pool owner.

 

[bgoz98]

Maybe. Some owners have been able to see growth once they made it a point to inspect carefully. One of those "out of sight - out of mind" things that sometimes catches up to a pool owner.

Left the pool cover open overnight and did the OCLT and failed it (lost 3 FC overnight and CC went from 0 to 1). It was a very windy day and had lots of pollen/leaves in the pool. Is this the likely cause for the CC change? It was back to zero after adding chlorine and testing at lunch today (still lost another 2.5 FC, likely due to sun). Should I go another night with the cover open to see what happens? Or has this result ruled out the underside of the cover being the culprit?

Also, how long does a "typical" SLAM last? I am on day 3 at this point. Not sure if this is short/normal/long, etc. I am following all of the rules to a T and not really seeing much change in results. My water is crystal clear. My CC has been zero (outside of this morning), but can't pass a OCLT. Filter pressure has also been back to standard after the initial test. I have noticed some white grainy substance in my robot vac. Not sure if this is dead algae, but kind of looks like white sand visually. There isn't a ton of it or anything. Maybe I am just being impatient (likely true).

 

[Texas Splash]

Is this the likely cause for the CC change?

A bunch of junk might have a slight effect on your levels, but not 3 ppm worth.

Should I go another night with the cover open to see what happens?

You are still in teh middle of your SLAM correct? If so, I owuld leave it off.

how long does a "typical" SLAM last? I am on day 3 at this point. Not sure if this is short/normal/long, etc.

This can vary widely. Some are fortunate enough to complete a SLAm in a few days, while others takes a week or two. Green swamps even longer.

With clear water, I think the only thing in your notes above not inspected yet was the light correct? Behind it in the niche? Seems like that is the only other thing in your water that could hide algae?

 

[bgoz98]

Correct, I am still SLAMing so will leave cover off.

On the light, do you mean around the edges of the light cover? Or are you saying disassemble the light altogether? Sorry, not familiar with its design with regard to the niche. The only other areas are the jets, returns, and the trim piece around the skimmer intake. Would I need to take those off and scrub?