6 Days Into Slam - Still Losing FC

[Mdragger88]

@SteveSwims
Be sure its been at least 30 minutes since your last addition. Maybe a tad longer since you only have the combo return/skimmer.
Do your best to do the test the same way each time.
Don’t squeeze the bottle, only the slightest pressure, let the drops fall pretty naturally. Should be about a drop per second. Find a rhythm. The faster the drops come out the higher the results will be ending in a skewed result.
A speed stir really helps you be able to solely concentrate on the drops if the constant swirling trips you up.

As for the chlorine strength - above 12% is pretty unstable and degrades quickly.
Always check the dates if possible to get the freshest stuff.

 

[VinnyinNJ]

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!

Drop size matters. A smaller drop will require more drops to turn red into clear. Stirring matters as well. Try to hold the bottle totally upside down and if a drop doesn't form a gentle squeeze will give you "the right size drop". I'm talking about a barely perceptual squeeze. Holding the bottle on its side could give you a smaller drop size. Make sure you mix the drops well if you are swirling by hand, don't just put a drop in and swirl once.

It gets easier once you get the hang of it! The good news it's not like you are 4 or 5 PPM off ... I did a salt test on my pool back to back and one came in at 2800 and another came in at 3000 - 1 drop off!

 

[SteveSwims]

Thanks both.

I’ll m using a Taylor speed stir actually.

I usually find that when I first tip the bottle upside down (making sure it’s vertical), 3 or 4 drops come out by themselves, then it stops and I have to apply slight pressure to the bottle to get them dripping again.

I’m trying to squeeze just hard enough to get around 1 drop per second

 

[Mdragger88]

If its a new bottle of reagent then wipe the tip with a paper towel before the next couple of tests to eliminate any static issues.

 

[Bperry]

Thanks both.

I’ll m using a Taylor speed stir actually.

I usually find that when I first tip the bottle upside down (making sure it’s vertical), 3 or 4 drops come out by themselves, then it stops and I have to apply slight pressure to the bottle to get them dripping again.

I’m trying to squeeze just hard enough to get around 1 drop per second

That may be whats going on. Before you pick up the bottle, squeeze the bottle a little to get some air out and then tip it over to add drops. It should be more controlled that way.

 

[RyanSim]

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!

Could be sample temperature or reagent drop sizes. Make sure reagent bottles are completely vertical when adding drops to your sample. But I'd have to say these titration test can have errors.

 

[SteveSwims]

About the speed stir, is there an optimal order to set it up?

Before, I was setting it running and then adding the powder and starting the drops but I noticed that the addition of the powder would make the stirring bar jump and catch for a few seconds (I dry the test tube as much as possible and am also using fresh batteries).

I started to instead add the power before adding the mixing bar and it seemed to mix much smoother (still catches slightly now and then).

The mixing bar is also getting a little discoloured at each end but I rinse it after every test.

Probably doesn’t make a difference but thought I’d mention.

I’m also trying to make sure that the meniscus of the water sampl is on the 10ml line (rather than having the water line on the 10ml line). Not sure how much difference it makes to the results if the meniscus is slightly lower or higher than the 10ml line though

 

[SteveSwims]

That may be whats going on. Before you pick up the bottle, squeeze the bottle a little to get some air out and then tip it over to add drops. It should be more controlled that way.

Ah, thanks! I’ll try that!

 

[VinnyinNJ]

About the speed stir, is there an optimal order to set it up?

Before, I was setting it running and then adding the powder and starting the drops but I noticed that the addition of the powder would make the stirring bar jump and catch for a few seconds (I dry the test tube as much as possible and am also using fresh batteries).

I started to instead add the power before adding the mixing bar and it seemed to mix much smoother (still catches slightly now and then).

The mixing bar is also getting a little discoloured at each end but I rinse it after every test.

Probably doesn’t make a difference but thought I’d mention.

I’m also trying to make sure that the meniscus of the water sampl is on the 10ml line (rather than having the water line on the 10ml line). Not sure how much difference it makes to the results if the meniscus is slightly lower or higher than the 10ml line though

I usually get the sample of water, put the vial onto the stirrer, drop the pill in and start it up. I then get my powder, close up the vial and grab the drops.

Just a FYI which is just my opinion ... the first couple of drops testing FC shouldn't matter assuming they look to be about the correct size. Having 3 drops of the correct size means 1.5 PPM chlorine. As you get closer to the finality of testing is where the most control needs to be. When I was running 13 PPM chlorine, if 5 drops come out quickly I knew that was 2.5 PPM and I would go from there. Other's may have a different and more correct way of doing it but it serves my purpose when running 6+ PPM chlorine.

 

[Bperry]

About the speed stir, is there an optimal order to set it up?

Before, I was setting it running and then adding the powder and starting the drops but I noticed that the addition of the powder would make the stirring bar jump and catch for a few seconds (I dry the test tube as much as possible and am also using fresh batteries).

I started to instead add the power before adding the mixing bar and it seemed to mix much smoother (still catches slightly now and then).

The mixing bar is also getting a little discoloured at each end but I rinse it after every test.

Probably doesn’t make a difference but thought I’d mention.

I’m also trying to make sure that the meniscus of the water sampl is on the 10ml line (rather than having the water line on the 10ml line). Not sure how much difference it makes to the results if the meniscus is slightly lower or higher than the 10ml line though

The trouble with adding the mixing bar after the powder is that it can splash up and you might lose some of it, I put the water in, then the bar, then the powder/drops. Its pretty consistsnt that way.

 

[SteveSwims]

Time for the next test.

Just got 15.5ppm so tested again and got 14ppm again.

I think if I go a bit too fast then that’s resulting in the higher results (usually anround 15.5 / 16ppm) and if I slow it down then I get the 14ppm result.

If that’s true then I guess I can assume my FC levels are virtually unchanged as the high and low results have been consistent all day (ie it’s not like I’ve been getting totally different results at every test). If yes then I’m getting virtually the same FC results since 11:15pm last night (currently 2:42pm in the U.K.) and I’ve not added any LQ at all today.

Maybe I’m almost there!

 

[SteveSwims]

Was at 12ppm FC at 10:00pm last night.

Tested again at around 5:45am this morning and initially got 10ppm but I think I did the drops too quickly so tested again twice more and got 11.5ppm on both further tests, so a drop of 0.5ppm overnight.

So I guess the SLAM is finally passed!

 

[Bperry]

Was at 12ppm FC at 10:00pm last night.

Tested again at around 5:45am this morning and initially got 10ppm but I think I did the drops too quickly so tested again twice more and got 11.5ppm on both further tests, so a drop of 0.5ppm overnight So I guess the SLAM is finally passed!

Only if there are 0.5ppm CC or less and no visible algae.

 

[SteveSwims]

Only if there are 0.5ppm CC or less and no visible algae.

Yep, never had any visible algae and CC has always beeen between 0 / 0.5. The only issue I ever noticed was fast FC loss.

Just topped back up to 12ppm this morning to make sure and then I guess it’s just a case of letting it lower naturally? I assume I have to keep an eye on how fast it drops though to make sure it doesn’t drop too quickly?

 

[Bperry]

Yep, never had any visible algae and CC has always beeen between 0 / 0.5. The only issue I ever noticed was fast FC loss.

Just topped back up to 12ppm this morning to make sure and then I guess it’s just a case of letting it lower naturally? I assume I have to keep an eye on how fast it drops though to make sure it doesn’t drop too quickly?

Test your CYA once more and then just chlorinate according to the chart going forward. Lowering Speed doesnt matter as you can be swimming the whole time anyway.

 

[SteveSwims]

Test your CYA once more and then just chlorinate according to the chart going forward. Lowering Speed doesnt matter as you can be swimming the whole time anyway.

I wasn’t worried about the speed before I couldn’t swim. I was thinking more about making sure it doesn’t fall too fast as that would indicate the FC consumption wasn’t solved?

I also noticed I need to top up the water now, as it’s fallen below the markers on my Aqua genie.

I last topped up about 3 weeks or so ago, just using my hose from the outside tap on the pool house wall.

I’m slightly worried that maybe I introduced something to the pool when I topped up (as I noticed the need to SLAM after this).

I’m most likely just being ultra paranoid but are there any tips for topping up? Is just using a house from an outside tap ok? Would it be worth topping FC up to SLAM level just for a short while after topping up the water to be safe?

 

[Bperry]

I wasn’t worried about the speed before I couldn’t swim. I was thinking more about making sure it doesn’t fall too fast as that would indicate the FC consumption wasn’t solved?

I also noticed I need to top up the water now, as it’s fallen below the markers on my Aqua genie.

I last topped up about 3 weeks or so ago, just using my hose from the outside tap on the pool house wall.

I’m slightly worried that maybe I introduced something to the pool when I topped up (as I noticed the need to SLAM after this).

I’m most likely just being ultra paranoid but are there any tips for topping up? Is just using a house from an outside tap ok? Would it be worth topping FC up to SLAM level just for a short while after topping up the water to be safe?

If the SLAM is done, it’s done. Add water as needed and just keep the FC above the minimum level. A little extra isn’t a big deal.

 

[SteveSwims]

Last night at 9:08pm, FC was 12pm, this morning at 7:09am is was 11ppm, so a drop of 1ppm.

The previous nights drop was only 0.5ppm but admittedly the time I left between tests then was a bit shorter than I left last night.

Would that fact, combined with the inbuilt tolerance thresholds of the test, be enough to still consider a OCLT pass, or should I be concerned that OCLT loss increased by 0.5ppm last night and continue the SLAM
(I believe FASDPD tolerance / accuracy drops to +-10% once you hit 20 drops?)?

 

[Bperry]

Last night at 9:08pm, FC was 12pm, this morning at 7:09am is was 11ppm, so a drop of 1ppm.

The previous nights drop was only 0.5ppm but admittedly the time I left between tests then was a bit shorter than I left last night.

Would that fact, combined with the inbuilt tolerance thresholds of the test, be enough to still consider a OCLT pass, or should I be concerned that OCLT loss increased by 0.5ppm last night and continue the SLAM
(I believe FASDPD tolerance / accuracy drops to +-10% once you hit 20 drops?)?

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.

 

[sande005]

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.