6 Days Into Slam - Still Losing FC

[SteveSwims]

Hi all

I am currently on day 6 of a SLAM due to high FC loss.

The water appears crystal clear and CC is always 0 / 0.5

However, I’m consistently losing around 4 / 4.5 ppm FC overnight (was initially losing around 7 / 8ppm FC overnight before the SLAM though and often woke up to 0 FC).

I’ve used around 50L of 14/15% liquid chlorine so far (although I suspect concentration is actually a bit lower so I’ve been topping up the doses slightly compared to the Pool Math dosage recommendation).

It’s about a simple a pool as you can get. Single depth, no lights etc…, a single Aqua Genie skimmer/return combo.

I’m trying to brush the walls etc.. when I can and have spent a lot of time cleaning up the Aqua Genie (as it was pretty filthy inside).

Am I missing something or do I just keep going?

Due to work, I’ve only been able to test/add chlorine early in the morning and from late afternoon onwards since Monday so I guess that’s not helping. I’m working from home from tomorrow though so plan to get back on every 2 hours.

it’s an “indoor” (in a glass & plastic conservatory) 10000 gallon in ground pool.

For what it’s worth, I also have a cheap UV meter which shows virtually no UV coming in through the clear plastic roof panels (not sure on the meters accuracy but as soon as I left the pool house the UV readings shoot up).

Just want some reassurance / ideas if possible please (as the costs are really starting to ramp up with the chlorine, electricity from the pump running 24/7 etc… not to mention how much of my time it’s taking up)

PS pictures from this morning

 

[SteveSwims]

PPS: I’m using a Taylor K2006 FAS DPD with Taylor Speedstir. 10ml sample with 1 heaped scoop of powder.

I have to order my reagents from Amazon US (as not available in the U.K.) and they are shipped as loose bottles in regular brown Amazon padded envelopes. As they are not shipped in any kind of specialist packaging, I’m not sure if that could maybe make them go bad / affect them in some way whilst in transit (thinking of them sitting in air cargo hold for the flight over the Atlantic)!

Might be clutching at straws but worth mentioning.

 

[VinnyinNJ]

Have you brushed the surfaces to remove algae on the surfaces? Are you sure that you are getting the correct dosage of chlorine into the pool? Depending on your CYA level you may need a lot of chlorine, I run a CYA of about 90 due to using a SWG and my slam was in the 30 PPM FC range. The fact that you are getting less chlorine usage sounds like your winning but just haven't won yet, hopefully someone with more knowledge comes along!

 

[SteveSwims]

@VinnyinNJ
Thanks for the reply.

I’m brushing the surfaces when I can, there is 0 visible algae anywhere as far as I can see but I’m brushing and vacuuming all the same.

CYA is 24 so recording as 30 for the purpose of Pool Math (indoor pool). Means SLAM level of 12.

As mentioned, I’m using 14/15% LQ but I’m not convinced it’s actually that strong (as using dosage recommendation for 14% LQ from Pool Math falls short when I test after adding).

I’m usually using Pool Maths dosage recommendation for 11% LQ and then adding a fraction more for good measure. When I test after adding, I’m generally hitting 12ppm FC (or a bit higher).

Stupid extra question but would a bottle of 14% LQ have the same strength as a bottle of 10% LQ (if dosed correctly to reach a desired PPM)?

I assume it’s a case of a tonne of feathers weighs the same as a tonne of bricks but just wanted to check!

 

[Bperry]

@VinnyinNJ
Thanks for the reply.

I’m brushing the surfaces when I can, there is 0 visible algae anywhere as far as I can see but I’m brushing and vacuuming all the same.

CYA is 24 so recording as 30 for the purpose of Pool Math (indoor pool). Means SLAM level of 12.

As mentioned, I’m using 14/15% LQ but I’m not convinced it’s actually that strong (as using dosage recommendation for 14% LQ from Pool Math falls short when I test after adding).

I’m usually using Pool Maths dosage recommendation for 11% LQ and then adding a fraction more for good measure. When I test after adding, I’m generally hitting 12ppm FC (or a bit higher).

Stupid extra question but would a bottle of 14% LQ have the same strength as a bottle of 10% LQ (if dosed correctly to reach a desired PPM)?

I assume it’s a case of a tonne of feathers weighs the same as a tonne of bricks but just wanted to check!

If you were losing 8ppm overnight then the SLAM is very unlikely to clear up in just a few days. So Id say its normal to be in 6 days and still seeing some loss, especially if you cant top it up more often. Many new people are expect a SLAM to just last 1-2 days but really swampy pools go for weeks.

Your CYA really ahould be a solid 30ppm minimum. It doesnt measure accurately below 30ppm.

 

[SteveSwims]

@Bperry

Thanks. I figured I was just hoping for too much, just surprised about how much chlorine I’m using as the water has always been clear and CC is always 0 / 0.5.

I guess not being available to top back up to SLAM level through the day for the last couple of days has slowed things down a bit too.

I’m hoping having the next 4 days at home will help get things moving!

Regarding CYA, as it’s an indoor pool I had previously started out aiming for 20 but had decided to raise it to 30.

I had some left over Dichlor granular so I used those to keep chlorine levels up and raise CYA a bit (came up from 14 to 24 last week).

As I understood that you round up CYA results to the next 10, I had assumed 24 would count as 30. Im actually using a Pool Lab 2.0 to test for CYA as my target levels are lower than the Taylor kit allows. Having said that, since raising to 24, the test solution with the Taylor kit does now go cloudy and obscures the dot when the tube is filled to just above the 20 line (previously the solution remained clear and the dot was visible all the way to the top).

 

[VinnyinNJ]

@VinnyinNJ
Thanks for the reply.

I’m brushing the surfaces when I can, there is 0 visible algae anywhere as far as I can see but I’m brushing and vacuuming all the same.

CYA is 24 so recording as 30 for the purpose of Pool Math (indoor pool). Means SLAM level of 12.

As mentioned, I’m using 14/15% LQ but I’m not convinced it’s actually that strong (as using dosage recommendation for 14% LQ from Pool Math falls short when I test after adding).

I’m usually using Pool Maths dosage recommendation for 11% LQ and then adding a fraction more for good measure. When I test after adding, I’m generally hitting 12ppm FC (or a bit higher).

Stupid extra question but would a bottle of 14% LQ have the same strength as a bottle of 10% LQ (if dosed correctly to reach a desired PPM)?

I assume it’s a case of a tonne of feathers weighs the same as a tonne of bricks but just wanted to check!

The ultimate way to know exactly what your amount of chlorine is in the pool is testing regardless of what a label or pool math says. So if you test and get the amount you are shooting for then you're good to go. If not and you need a little more add and if it was way too high ok and add a little less next time.

You're doing fine, your chlorine consumption is coming down and probably if you can test and adjust a few times a day then things may accelerate to the positive a little faster ... keep it up and don't get discouraged.

 

[Bperry]

@Bperry

Thanks. I figured I was just hoping for too much, just surprised about how much chlorine I’m using as the water has always been clear and CC is always 0 / 0.5.

I guess not being available to top back up to SLAM level through the day for the last couple of days has slowed things down a bit too.

I’m hoping having the next 4 days at home will help get things moving!

Regarding CYA, as it’s an indoor pool I had previously started out aiming for 20 but had decided to raise it to 30.

I had some left over Dichlor granular so I used those to keep chlorine levels up and raise CYA a bit (came up from 14 to 24 last week).

As I understood that you round up CYA results to the next 10, I had assumed 24 would count as 30. Im actually using a Pool Lab 2.0 to test for CYA as my target levels are lower than the Taylor kit allows. Having said that, since raising to 24, the test solution with the Taylor kit does now go cloudy and obscures the dot when the tube is filled to just above the 20 line (previously the solution remained clear and the dot was visible all the way to the top).

The pool lab thing will be a problem long term. Use it at your own risk. TFP advice is based on using TFP recommended test kit/process. Your CYA should be solidly above 30ppm on the taylor test kit.

 

[SteveSwims]

The pool lab thing will be a problem long term. Use it at your own risk. TFP advice is based on using TFP recommended test kit/process. Your CYA should be solidly above 30ppm on the taylor test kit.

@Bperry I’ll try to get my CYA to hit 30 on the Taylor then as I had wanted to do that anyway. Is it ok to do that during a SLAM or should I wait for the SLAM to finish first?

As mentioned, I’ve got some Dichlor granules left which I could add a small amount of to keep FC up and raise CYA slightly.

 

[VinnyinNJ]

Dichlor is roughly 50/50 chlorine and stabilizer.

 

[Bperry]

@Bperry I’ll try to get my CYA to hit 30 on the Taylor then as I had wanted to do that anyway. Is it ok to do that during a SLAM or should I wait for the SLAM to finish first?

As mentioned, I’ve got some Dichlor granules left which I could add a small amount of to keep FC up and raise CYA slightly.

As long as its not clorox, Xtra blue, Blu, etc which are code words for copper.

 

[SteveSwims]

As long as its not clorox, Xtra blue, Blu, etc which are code words for copper.

It’s sodium dichloroisocyanurate dihydrate in case that helps?? Manufacturer is Blue Horizons

 

[Bperry]

It’s sodium dichloroisocyanurate dihydrate in case that helps?? Manufacturer is Blue Horizons

As long as it’s Only that on the ingredients list, it’s fine

 

[SteveSwims]

Quick update, slightly overshot my SLAM FC target last night to try and give a bit of a boost (hit 17ppm instead of 12ppm). Added a bit of my granulated Dichlor and my CYA is now hovering around 30 too.

Have been working at home today so have been able to test every 2 hours. I’ve only lost 3ppm FC in the last 14 hours (including overnight) so I’m starting to get hopeful! Not had to add any chlorine to top back up to SLAM level since 8pm last night (uk time).

Currently sitting at 13ppm FC so will keep monitoring.

 

[VinnyinNJ]

Quick update, slightly overshot my SLAM FC target last night to try and give a bit of a boost (hit 17ppm instead of 12ppm). Added a bit of my granulated Dichlor and my CYA is now hovering around 30 too.

Have been working at home today so have been able to test every 2 hours. I’ve only lost 3ppm FC in the last 14 hours (including overnight) so I’m starting to get hopeful! Not had to add any chlorine to top back up to SLAM level since 8pm last night (uk time).

Currently sitting at 13ppm FC so will keep monitoring.

You may be over that hump of not getting anywhere! Glad it's getting better.

 

[SteveSwims]

Another update, FC was at 15.5ppm at around 11:15pm last night. Checked this morning at around 7:15am and dropped to 12.5.

Didn’t add any more LQ as was still above the SLAM target of 12 and had some stuff I had to do.

I’ve just checked again now (around 10:00am) and FC was reading at 14ppm! I did multiple tests to be certain (including using samples from a different area of the pool and also tried using a different pot of the FASDPD powder) and got consistent results.

Do I have to assume my test at 7:15am was botched or can FC rise by itself ever??

 

[VinnyinNJ]

FC doesn't go up by itself. It will only go up if you introduce something that'll add it. If the pool had a Salt Water Generator then that needs to be turned off, if you used pucks then they need to be taken out and things like that.

If nothing was added and you're getting consistent results then it sounds like the "bad" reading was the result of user malfunction!

The 3 criteria for a completing a SLAM I believe are 1) FC loss of less than 1 PPM, 2) CC less than 1 PPM and 3) no visible signs of living or dead algae. I think you said your pool is crystal clear so with no FC loss the only other criteria is what is you CC level *it should be 0 with no FC loss.

Sounds like you beat the algae!!

 

[SteveSwims]

I had figured it waa user malfunction but it’s good to have it confirmed!

I don’t think I’ve quite passed the below 1ppm FC loss test yet though. FC was at 15.5ppm at 11:15pm last night. If I remove the “botched” test result then the next test result was 14ppm FC around 11 hours later. I’ll keep SLAMing today and see how it gets on.

But yeah, water is absolutely crystal and CC is consistently 0/0.5

 

[VinnyinNJ]

I had figured it waa user malfunction but it’s good to have it confirmed!

I don’t think I’ve quite passed the below 1ppm FC loss test yet though. FC was at 15.5ppm at 11:15pm last night. If I remove the “botched” test result then the next test result was 14ppm FC around 11 hours later. I’ll keep SLAMing today and see how it gets on.

But yeah, water is absolutely crystal and CC is consistently 0/0.5

Sorry, I missed the 1.5 FC loss ... but you're well on your way to finishing!

 

[SteveSwims]

I’m losing the will to live here!

Just tested again 2 hours later and now reading 16ppm FC

Just when I think I’m getting ahead something always goes weird!

Can’t believe how difficult this is!

UPDATE: OK, just tested twice more and got 14 and 14.5ppm which is more in line with my test 2 hours ago. Maybe user error again I guess but I don’t think I did anything differently!