6 Days Into Slam - Still Losing FC

[SteveSwims]

Thanks all!

The pump has been running 24/7 for at least 2/3 weeks at this point.

I’ve switched to the “new” liquid chlorine for the last few additions (I.e the Liquipak brand) so will see if that has any impact.

In case it helps, I’ve done a rough and ready log of my OCLT results over the last couple of weeks (doesn’t show LQ additions during the day etc…). Can see an improvement over time I guess but it’s just so frustrating to pass the test for a few days only for it to regress again soon afterwards!

I’ve very rarely let it go below SLAM level in this time.

I guess I’ll just keep going for now!

 

[SteveSwims]

R0871 refill arrived yesterday afternoon.

Tested 12ppm FC and 0.5ppm CC at 10:15pm so didn’t add and LQ and left it for the night.

This morning, test showed 11.5FC and 0.5ppm, so the first OCLT pass in 4 days.

Only things different / noteworthy last night:

1: Only 2 dead bugs at the bottom of the pool this morning, lowest number in a few days.

2: I also had the Taylor Sample Sizer delivered yesterday so used that to measure my 10ml samples last night and this morning.

3: I gave my Aqua Genie skimmer another scrub last night. The water in the skimmer went cloudy as I was scrubbing so possibly algae?

Topped back up to 12ppm FC before I left for work this morning.

 

[SteveSwims]

Another 0.5pom FC drop last night. 2 in a row again now.

As a side note, I’ve bought a new vacuum head, which I’ve only used once and this morning have noticed some staining inside the weighted parts (the 3 white rectangles in the attached images).

Does this look like algae forming inside it or could it just be staining from the water interacting with the components of the head?

If it looks like algae then I don’t really want to use it again that’s all!

 

[Mdragger88]

For the vac head, I think thats just sand in those “bricks” for weight, shouldn’t be any metal. Maybe its not sealed well. Soak that baby in a bucket of bleach water and see if they go away.
Your oclt results are great. I call it a pass.
Let fc fall to high target & maintain that or a scootch above. You deserve a break!

 

[Newdude]

For the vac head, I think thats just sand in those “bricks” for weight, shouldn’t be any metal

My Hayward triangle head uses what appears to be lead. Maybe that one has iron (etc) but it's wrapped in plastic.

Or maybe just that the area around the weights doesn't breathe well so it's getting funky.

Either way Steve, it's not enough to affect anything.

 

[Mdragger88]

My Hayward triangle head uses what appears to be lead. Maybe that one has iron (etc) but it's wrapped in plastic.

Or maybe just that the area around the weights doesn't breathe well so it's getting funky.

Either way Steve, it's not enough to affect anything.

My triangle head is filled with sand but My brushes bristles do this- the head looks fine so I guess it’s whatever is inside holding them in- it happened after like 2 days of use!

 

[SteveSwims]

Thanks all!

I’m just probably over cautious / paranoid as the pool seems to have settled into a pattern of having a few consecutive nights of OCLT passes followed up by a few nights of OCLT fails over the last couple of weeks.

That’s just got me a bit confused about when to stop that’s all?

About the vacuum head, I’m not sure what material the weights are made out of (the listing doesn’t mention it) but by the sounds of it it’s not uncommon for them to discolour so maybe I’m just being paranoid about that also.

 

[SteveSwims]

Couple of questions.

When I let my FC level fall naturally from SLAM to target levels, if there is no longer a problem with the water then should it fall at a consistent rate untill it reaches target levels or will the FC level drop start to increase the longer I go without adding fresh LQ (just want to understand what I should look out for to indicate if there’s still a problem)?

When I’m back to my target FC, will the PH sort itself out naturally or will I need to take any action to correct that?

Thanks!

 

[Bperry]

Couple of questions.

When I let my FC level fall naturally from SLAM to target levels, if there is no longer a problem with the water then should it fall at a consistent rate untill it reaches target levels or will the FC level drop start to increase the longer I go without adding fresh LQ (just want to understand what I should look out for to indicate if there’s still a problem)?

When I’m back to my target FC, will the PH sort itself out naturally or will I need to take any action to correct that?

Thanks!

There’s nothing consistent in pool chemicals. They are always changing and don’t follow many helpful rules to make our lives easier. FC tends to degrade a percentage each day depending on heat, UV, and 10 other things. You just gotta test often enough and react accordingly.

 

[Mdragger88]

Test your ph when fc falls to 10ppm or below & adjust it if needed to remain in the 7’s.
The phenol red test is simply skewed by fc higher than 10ppm - the ph doesn’t actually change because of the high/lower fc.

 

[jakeblat]

From my own experience I lose 0.3 to 0.4ppm a day consistently if the pool remains covered. I can be reasonably sure if I've tested it at 6ppm (with CYA at 30) and the pool doesn't get much use I will need to add more chlorine in 6-7 days to stay well within the recommended values.

As your FC drops from SLAM level to the upper recommended level (non-SLAM), e.g. 6 for a CYA of 30, then test each day but do not add any more chlorine. If you are going to fall out of the recommended range then take action, but otherwise just wait and see how it behaves. You can then take your first day value minus your 3/4/5th day value and work out your average loss for X days.

 

[SteveSwims]

Lost 0.5ppm FC overnight so that was 4x OCLT passes in a row.

I’m really not feeling confident though after today. I stopped adding LQ this morning as a result of the 4x consecutive OCLT passes, to let the FC levels start to fall and have lost 2ppm in 13.5 hours today (between 6:30am and 8:00pm), which seems high compared to recent days.

Seems whenever I let my FC start to drop below SLAM level the loss rate increases rapidly again.

Anyway, I’ll do one more OCLT tonight and see what the results are and then I’ll just go for it and let the FC drop to the non SLAM target and see what happens!

 

[Bperry]

Lost 0.5ppm FC overnight so that was 4x OCLT passes in a row.

I’m really not feeling confident though after today. I stopped adding LQ this morning as a result of the 4x consecutive OCLT passes, to let the FC levels start to fall and have lost 2ppm in 13.5 hours today (between 6:30am and 8:00pm), which seems high compared to recent days.

Seems whenever I let my FC start to drop below SLAM level the loss rate increases rapidly again.

Anyway, I’ll do one more OCLT tonight and see what the results are and then I’ll just go for it and let the FC drop to the non SLAM target and see what happens!

Losing only 2ppm during the day is low for most of us.

 

[SteveSwims]

I know, it’s an indoor pool though and just comparing to the daytime losses that I’ve been seeing over the last few days.

Hoping I’m just being ultra paranoid, will find out tomorrow

 

[SteveSwims]

So it was another OcLT pass last night after all (5 in a row) although admittedly the loss last night was the biggest of the 5 nights (1ppm).

So I’m leaving the FC to fall now and see what happens.

Interestingly though I noted that my CYA was almost gone in the test I did today (always had it relatively low (30) but today the solution was virtually clear all the way to the top of the tube.

Not sure why, I have topped up the water level a couple of times in the last couple of weeks so I guess that counts as dilution maybe? Anyway, I guess I better too the CYA back up now anyway.

 

[SteveSwims]

FC seems to be holding well!

Not added LQ in 2 days now and it’s dropping from SLAM levels at a steady pace.

Did a full set of tests this evening and here are the results:

FC 8.5
CC 0
PH 8.0 (probably a bit higher though as was a bit darker than 8.0 on the Taylor comparator block)
TA 150
CH 700

Already know my CYA has dropped below 30 during the SLAM so will fix that.

Should I address the PH now or should I wait for my FC to come down a bit more before worrying about that?

 

[Newdude]

Ph is valid once the FC is below 10. It won't hurt to adjust it periodically with a long slam. It also won't hurt if you don't.

 

[SteveSwims]

Hi all, me again!

Since passing the SLAM, I’ve not had to add any LQ to my pool as the FC levels are dropping really slowly!

The last time I added LQ was on 31.08.24 (FC reading after adding was 12pm)

As of today, FC is sitting at 5.0 ppm (target level for my CYA).

I’ve gone from one extreme to the other with regards to FC loss. Am I being paranoid or is this slow loss rate ok? As always I’m questioning whether my Taylor reagents are still good but probably over thinking.

As a reminder, it’s an indoor pool so UV is virtually not an issue.

I should also add that no one has actually been in the pool yet since passing the SLAM.

In the meantime I’ve also raised my CYA (now the dot disappears at the 30 line so I’m reading as 40) and have also been reducing my TA (now down from 150 to 100).

 

[Mdragger88]

Total fine be sure to stay in target range & not dip to minimum & you’ll be golden

 

[Newdude]

An indoor pool with limited bather load will have very little loss, if any.