6 Days Into Slam - Still Losing FC

[SteveSwims]

Google tells me sunrise is currently at 5:55am in London. So you had maybe an hour of sun on the pool before testing. That may have a small impact on the apparent chlorine loss.

Yeah, true. It’s actually an indoor pool so UV should be minimal but definitely a possible (plastic roof panels which do block almost all UV according to my UV meter but no way of knowing how accurate it is!).

The previous nights OCLT (where overnight FC loss of 0.5ppm was recorded), I did the morning test before sunrise (tested at 5:45am) so I guess I should try the same again tomorrow to be certain!

 

[SteveSwims]

Losing 1ppm OR less is a pass. Only fail if you lose more than 1ppm. That said, extending a day is good insurance. Also make sure CC is 0.5 or less.

I’ll give it another day and will see then.

CC is 0

 

[SteveSwims]

I don’t know what to do!

Last night at 9:08 FC was 12.5ppm

This morning at 6:15 it’s 10.5ppm

What else can I do??

I only moved into this house in May and have not been able to get this water right.

I think I’m at the point where I might just get the pool filled in as this just feels like too much hassle.

One thing to note, 3 nights ago I got 0.5ppm FC drop and I only left 7h45 mins between tests, for the 2 subsequent OCLTs I have left between 9/10 hours between tests. Is that too long?

 

[jakeblat]

Hi Steve,

Try to continue the SLAM a few more days, it's not always a fast process. Just to check is there anything that's changed in the last few days? e.g. the cover is back on when it had been off before?

Once you do get on top of it the ongoing maintenance will be much easier. I know what to expect and only test my pool a couple times a week because everything is very stable with it being indoors and shielded from debris and UV.

I'm guessing you're ~£450 in with the test kits and bleach which isn't much more than you'd pay for a company to come and open the pool and visit a few times (and still not get rid of the algae).

Re: filling the pool, you'll forget about this initial pain once you've cleared the SLAM and everyone gets to enjoy the pool. Also you'd be surprised just how much it can cost to fill in, I checked before I committed to~£15k on renovations to get everything back to working order.

 

[SteveSwims]

Hi Steve,

Try to continue the SLAM a few more days, it's not always a fast process. Just to check is there anything that's changed in the last few days? e.g. the cover is back on when it had been off before?

Once you do get on top of it the ongoing maintenance will be much easier. I know what to expect and only test my pool a couple times a week because everything is very stable with it being indoors and shielded from debris and UV.

I'm guessing you're ~£450 in with the test kits and bleach which isn't much more than you'd pay for a company to come and open the pool and visit a few times (and still not get rid of the algae).

Re: filling the pool, you'll forget about this initial pain once you've cleared the SLAM and everyone gets to enjoy the pool. Also you'd be surprised just how much it can cost to fill in, I checked before I committed to~£15k on renovations to get everything back to working order.

No, no changes. Cover has been off for a couple of weeks now and have not put the pool ladder etc… back in.

The only change I did was on Friday, I removed the old weir flap and replaced with a new one as it was sticking. But I then recorded my OCLT result of 0.5ppm on the Sunday morning so don’t think that is related.

I actually have been actively trying to replace / keep away as many of the existing pool accessories etc… as possible as I don’t want to risk adding anything back in that may be on the things left behind by the previous owner.

Having said that, my son did splash his pool noodles into the water on Sunday(just hitting the water with them from outside the pool) maybe only for a couple of minutes.

Admittedly, on Sunday I did immediately pull back on the testing / topping up to SLAM levels etc… as assumed the SLAM was passed. I tooped FC back up to SLAM level on Sunday evening but hadn’t done anything in the meantime. I was then back working all day on Monday so haven’t been able to monitor / test through the day (same for today).

I guess I maybe cut back on the SLAM too soon after I saw 0.5ppm OCLT, 0 CC and clear water on the Sunday morning. However, from the tests that I have done since passing the OCLT, FC has not dropped below 11ppm (SlAM target is 12ppm), untill this morning!

I also notice so many bugs in the pool, even being indoors. Usually 5 / 6 flies etc… of various sizes in the skimmer basket and 2/3 wood lice on the pool floor in the morning.

I assume they will contribute to lowering FC but not sure if they would lower by 1ppm/2ppm?

 

[SteveSwims]

I really have a dislike for the Aqua Genie skimmer too (for a few reasons). It has so many crevices / covered areas etc… which allow dirt to get stuck, plus the previous owner seems to have never cleaned it.

I have been scrubbing it loads since starting the SLAM and it’s a lot cleaner now but I saw a lot of dark coloured patches under the chlorine tablet canister shelf (hopefully visible in the pic). I think these are mostly staining as they don’t come off at all but it doesn’t help me have much confidence in it!

Do you think I would be ok to cut away the chlorine canister shelf to give better access / visibility to that area or am I just being too paranoid there?

 

[SteveSwims]

Sorry, just another thing (as trying to list everything I can think of), I notice that the pool house (mostly glass and brick walls with plastic roof panels - images below show construction) gets covered in condensation overnight, which forms on the roof panels and allows drips back down to the pool. Rain also drips through l.

Not sure if either of those things could be introducing further dirt etc…. to the water in enough quantities to have an impact?

 

[Bperry]

Sorry, just another thing (as trying to list everything I can think of), I notice that the pool house (mostly glass and brick walls with plastic roof panels - images below show construction) gets covered in condensation overnight, which forms on the roof panels and allows drips back down to the pool. Rain also drips through l.

Not sure if either of those things could be introducing further dirt etc…. to the water in enough quantities to have an impact?

Relax a bit, maybe go swim! Losing 1ppm FC overnight isn’t something to worry enough about to fill the pool in. Check it again tomorrow.

 

[SteveSwims]

Relax a bit, maybe go swim! Losing 1ppm FC overnight isn’t something to worry enough about to fill the pool in. Check it again tomorrow.

Good advice (British people tend to be more on the pessimistic side by nature )

I didn’t lose 1ppm overnight though, I have gone from losing 0.5ppm overnight on Saturday night (thinking I had finished the SLAM on Sunday morning ) to already losing 2ppm overnight 2 nights later (meaning SLAM isn’t over).

Perhaps I jumped the gun and finished the SLAM a bit early after reaching 0.5 OCLT, 0 CC and clear water but just trying to think of possible causes.

 

[Bperry]

I didn’t lose 1ppm overnight though, I have gone from losing 0.5ppm overnight on Saturday night (thinking I had finished the SLAM on Sunday morning ) to already losing 2ppm overnight last night (meaning SLAM isn’t over).

Perhaps I jumped the gun and finished the SLAM a bit early after reaching 0.5 OCLT, 0 CC and clear water but just trying to think of possible causes.

Sorry, I meant losing 1ppm “extra” overnight. It’s nearly impossible to not lose any FC overnight so we consider 1ppm to be an acceptable pass. You just lost a bit more than “nothing”. It could be a fluke, or something wasn’t quite dead, etc. Either way, it’s nothing to worry about since you are testing and responding to the tests with a plan of action. Don’t over worry about pool noodles or extra dirt. Your almost there!

 

[SteveSwims]

No problem, I appreciate the help and encouragement!!

FC dropped by 2ppm during the day today whilst ie as at work. Still seems too high for an indoor pool which had supposedly cleared the SLAM tests 2 days ago.

Did a full set of tests tonight as hadn’t done so in a while (using Taylor K2006 with the exception of CYA):

FC: 13.5
CC: 0
CYA: 26 (using Pool Lab 2.0, counting as 30 for pool math)
PH: 8.0 (maybe higher, seemed a bit darker than the 8.0 max)
TA: 150
CH: 725

I guess I ignore PH for now as I understand that the SLAM sends PH crazy?

Anything else stand out as a possible cause?

 

[Bperry]

Brand new chlorine in a closed bottle from the store will degrade just from heat and time. So 2 ppm during the day does not seem like very much in the summer. Even for an indoor pool. What’s the water temperature?

 

[SteveSwims]

That’s good to know.

Water temp was around 25c today.

FC didn’t actually drop any further when I tested again at around 9:00pm tonight (still at 13.5, line it was at 6:40pm).

 

[SteveSwims]

9:00pm last night: FC = 13.5ppm

5:50am this morning: FC = 11.5ppm

OCLT failed for the 2nd night in a row after passing it for the previous 3 nights in a row.

Genuinely don’t know what’s happened, or how something could have got back in the pool so fast.

Pool Math shows my SLAM target to be 12pm FC but I passed the OCLT by overshooting that target between Thursday and Sunday last week (was usually sitting between 13/15 ppm).

Maybe I just need to keep at that level again for a few days instead so I’ve overshot again this morning (will be at work all day though!).

One thing, since I moved in there has been a small, thin, maybe 2 or 3 inch long yellowish mark on the floor of the pool, in one of the corners. I’d assumed this was just a stain of some kind as I’d never been able to remove it (had only given it a light brush), however this morning I scrubbed it a bit more vigorously with the pole brush and I’m sure it actually faded a bit.

The picture isn’t the clearest in the world (taken after scrubbing this morning) but this couldn’t be algae all along could it??

 

[Bperry]

9:00pm last night: FC = 13.5ppm

5:50am this morning: FC = 11.5ppm

OCLT failed for the 2nd night in a row after passing it for the previous 3 nights in a row.

Genuinely don’t know what’s happened, or how something could have got back in the pool so fast.

Pool Math shows my SLAM target to be 12pm FC but I passed the OCLT by overshooting that target between Thursday and Sunday last week (was usually sitting between 13/15 ppm).

Maybe I just need to keep at that level again for a few days instead so I’ve overshot again this morning (will be at work all day though!).

One thing, since I moved in there has been a small, thin, maybe 2 or 3 inch long yellowish mark on the floor of the pool, in one of the corners. I’d assumed this was just a stain of some kind as I’d never been able to remove it (had only given it a light brush), however this morning I scrubbed it a bit more vigorously with the pole brush and I’m sure it actually faded a bit.

The picture isn’t the clearest in the world (taken after scrubbing this morning) but this couldn’t be algae all along could it??

If it’s going away with chlorine, then it’s likely organic. Hard to say what kind.

One thing to be careful of about overshooting the chlorine. The OCLT criteria is designed to work when the FC is at SLAM level or below. If FC is going above that, then you may lose more than expected. It also assumes you actually have enough CYA in the water when tested by the Taylor kit. I’m more concerned about the pool lab thing. Those things have led many people astray chasing things that weren’t there. Does your Taylor kit say the CYA is a solid 30ppm, not a 21 rounded up to 30?

 

[SteveSwims]

If it’s going away with chlorine, then it’s likely organic. Hard to say what kind.

One thing to be careful of about overshooting the chlorine. The OCLT criteria is designed to work when the FC is at SLAM level or below. If FC is going above that, then you may lose more than expected. It also assumes you actually have enough CYA in the water when tested by the Taylor kit. I’m more concerned about the pool lab thing. Those things have led many people astray chasing things that weren’t there. Does your Taylor kit say the CYA is a solid 30ppm, not a 21 rounded up to 30?

Hey @Bperry

The stain isn’t going away with chlorine, it’s been there since I moved into the house in May. I have tried scrubbing it before but it didn’t seem to do anything. This morning I scrubbed it a bit harder though and it did seem to fade so I’ll keep at it and see what happens!

I had actually run out of my Taylor CYA reagent but have more coming tomorrow at last! Last time I used the Taylor CYA test though (a week or so ago) it went cloudy just above the 30 line (so not quite 30 I’d say, which lines up with the reading of 26 on the Pool Lab).

I will definitely test again with the Taylor CYA test tomorrow though.

I had thought CYA would only have an impact during the day though so not sure if that would explain the overnight loss?

I have been telling Pool Math that my CYA was 30 though and aiming for the related SLAM FC.
If the Taylor CYA test still reads below 30 tomorrow then for sure I’ll top up my CYA again to try and get it over that line!

Happy to try anything at this point!

That’s interesting about the OCLT and overshooting SLAM FC though. I’ll also try an OCLT when I’m at or just below The exact SLAM level then, thanks!

 

[Bperry]

Hey @Bperry

The stain isn’t going away with chlorine, it’s been there since I moved into the house in May. I have tried scrubbing it before but it didn’t seem to do anything. This morning I scrubbed it a bit harder though and it did seem to fade so I’ll keep at it and see what happens!

I had actually run out of my Taylor CYA reagent but have more coming tomorrow at last! Last time I used the Taylor CYA test though (a week or so ago) it went cloudy just above the 30 line (so not quite 30 I’d say, which lines up with the reading of 26 on the Pool Lab).

I will definitely test again with the Taylor CYA test tomorrow though.

I had thought CYA would only have an impact during the day though so not sure if that would explain the overnight loss?

I have been telling Pool Math that my CYA was 30 though and aiming for the related SLAM FC.
If the Taylor CYA test still reads below 30 tomorrow then for sure I’ll top up my CYA again to try and get it over that line!

Happy to try anything at this point!

That’s interesting about the OCLT and overshooting SLAM FC though. I’ll also try an OCLT when I’m at or just below The exact SLAM level then, thanks!

I’d Test again when the stuff arrives and add enough CYA to get a solid 30 to 40 ppm. If you’ve been overshooting the slam when you start your OCLT then there’s a good chance that’s contributing as well.

 

[SteveSwims]

Only dropped 0.5ppm FC in 12 hours during the day today, tested this morning before work and just tested again now this evening.

Will still test CYA with the Taylor tomorrow and too upto 30 if needed.

I also really need to top up my water too as have dropped below the waterline markers (I suspect a leak in my skimmer but that’s a different matter ). Am I ok to add water during a SLAM or better to wait untill it’s finished first?

 

[Bperry]

Only dropped 0.5ppm FC in 12 hours during the day today, tested this morning before work and just tested again now this evening.

Will still test CYA with the Taylor tomorrow and too upto 30 if needed.

I also really need to top up my water too as have dropped below the waterline markers (I suspect a leak in my skimmer but that’s a different matter ). Am I ok to add water during a SLAM or better to wait untill it’s finished first?

Adding a little water won’t change tests enough to notice. It’s very odd you lose more FC at night than during the day… the UK isn’t up close to the North Pole where they have 20 hour of darkness and 4 hours of daylight is there?

 

[SteveSwims]

You’re right, I just did my last test for the day (10:06pm here) and got 16ppm FC.

A drop of 1ppm in 4 hours (after only dropping

Adding a little water won’t change tests enough to notice. It’s very odd you lose more FC at night than during the day… the UK isn’t up close to the North Pole where they have 20 hour of darkness and 4 hours of daylight is there?

yeah, it’s pretty odd!

As mentioned, it is an indoor pool though which I guess means that UV doesn’t have the same impact and maybe chlorine loss behaves differently. Who knows!

Will see what I get in the morning anyway!