Chlorine loss problem

[ajw22]

So could be cover causing the drop even though I have trimmed dirty sections.

I believe if one area is visibly grungy you have algae in many other places on the cover. It needs to be replaced if the entire cover cannot be given a long chlorine bath and scrubbed at SLAM FC levels.

 

[Karlosw]

I believe if one area is visibly grungy you have algae in many other places on the cover. It needs to be replaced if the entire cover cannot be given a long chlorine bath and scrubbed at SLAM FC levels.

I just managed to semi-submerse it and scrub the surface. Will see how that goes.

 

[Texas Splash]

Curious to see how your next OCLT goes without that cover in play. Surprised you didn't see junk behind that light cover. I would've put $$ on it.

 

[Youfah Mizzum]

@Karlosw , you've already done what I would've suggested to get rid of those black marks on your cover. Cut them buggers off!

Despite what others have said to remove the cover - I think you should keep the pool covered during SLAM. I know it introduces another element in the fight but it's a normal & essential element in your pool equipment so might as well deal with it as such. It might extend SLAM another 2 or 3 days but at least the cover is getting dealt with along with all other elements.

Try to keep the cover submerged while SLAMming as the higher chlorine will deal with hidden nasties. The fact that you managed to semi-submerge it and give it a scrub on the top surface is pretty good. It's hard but can you invert the cover and scrub the underneath?

With a night test at 13 then a morning test at 13 (13.5?) then it looks like you're winning.

Keep going another few days.

 

[Karlosw]

@Karlosw , you've already done what I would've suggested to get rid of those black marks on your cover. Cut them buggers off!

Despite what others have said to remove the cover - I think you should keep the pool covered during SLAM. I know it introduces another element in the fight but it's a normal & essential element in your pool equipment so might as well deal with it as such. It might extend SLAM another 2 or 3 days but at least the cover is getting dealt with along with all other elements.

Try to keep the cover submerged while SLAMming as the higher chlorine will deal with hidden nasties. The fact that you managed to semi-submerge it and give it a scrub on the top surface is pretty good. It's hard but can you invert the cover and scrub the underneath?

With a night test at 13 then a morning test at 13 (13.5?) then it looks like you're winning.

Keep going another few days.

Thanks mate. Good news FC at 15ppm after the whole day with the cover on (now 7.30pm). I’m glad to have just trimmed an inch around the outside rather than throw the whole thing out (saved myself $1k). I spoke with the manufacturer and they indicated a quick brush around the edges is good enough to clear out any muck. The air cushions are only about a square inch in size so with the offending areas removed I was struggling to see how the whole cover would be lost.

I was thinking of inverting it, but then again the parts that could spread algae into the water are all in contact with the water anyway. I just needed to get rid of the worst offenders.

Will see how the overnight test goes, but losing 1ppm of the whole day should mean the overnight test will go okay.

As per your experience, I will keep up the slam for a bit longer just to make sure. Hopefully the low chlorine loss continues.

Thanks everyone of the advice and assistance. Certainly has helped with the process to have all the help.

 

[Texas Splash]

Will see how the overnight test goes, but losing 1ppm of the whole day should mean the overnight test will go okay.

A very good sign indeed. Algae, it's a sneaky bugger. Good you found it.

 

[Karlosw]

A very good sign indeed. Algae, it's a sneaky bugger. Good you found it.

Just gave the cover another scrub (semi-submerged). So hopefully got everything…

 

[Karlosw]

Just gave the cover another scrub (semi-submerged). So hopefully got everything…

6am FC at 14.5 so not quite there yet. But that is the best overnight result to date.

 

[Texas Splash]

6am FC at 14.5 so not quite there yet. But that is the best overnight result to date.

Great!

 

[JoyfulNoise]

15ppm to start and 14.5ppm by the next morning? That’s passing for an OCLT. If true, end the SLAM and move on.

 

[Karlosw]

15ppm to start and 14.5ppm by the next morning? That’s passing for an OCLT. If true, end the SLAM and move on.

It was 16ppm to start with. However, pool has since passed the OCLT.

 

[Karlosw]

Great!

Now that the slam is finished, what is the best way to get the CYA levels back up? Should I boost the CYA level up to 70 now and then slowly lower chlorine levels or should I lower chlorine and then boost CYA levels. Assuming that I haven’t lost any CYA since last test, it should be around 40ppm.

By the way, went the whole day today with almost no chlorine loss.

 

[Texas Splash]

what is the best way to get the CYA levels back up?

Add the required amount of granular stabilizer via the sock method. It works very well. Since your CYA is estimated to be about 40, I would only add about 20 ppm worth to ensure you don't go too high. 70 is ideal, but best to be cautious, plus your seaons is coming to an end shortly. You can always add a little more stabilizer later if needed.

Don't worry about the FC level. It will slowly fall on its own.

 

[Texas Splash]

In case it helps.......

Adding CYA:
To increase CYA via granular stabilizer, place the required amount as calculated by the Poolmath calculator into a white sock and place in the poolside skimmer basket. For those concerned about suction flow to the pump, suspending the sock near a return jet or from a floating device will also suffice. Best never to allow undissolved granules to rest directly against the pool surface. After soaking for about 20-30 minutes, squeeze the sock often to help it dissipate. Once dissolved, consider your CYA adjusted to that programmed (target) level. CYA test readings should show a rise in 24-48 hours, however some pools may experience a longer delay to fully register. Best to confirm final CYA in about 5-7 days before adding any more stabilizer/conditioner.

 

[Karlosw]

In case it helps.......

Adding CYA:
To increase CYA via granular stabilizer, place the required amount as calculated by the Poolmath calculator into a white sock and place in the poolside skimmer basket. For those concerned about suction flow to the pump, suspending the sock near a return jet or from a floating device will also suffice. Best never to allow undissolved granules to rest directly against the pool surface. After soaking for about 20-30 minutes, squeeze the sock often to help it dissipate. Once dissolved, consider your CYA adjusted to that programmed (target) level. CYA test readings should show a rise in 24-48 hours, however some pools may experience a longer delay to fully register. Best to confirm final CYA in about 5-7 days before adding any more stabilizer/conditioner.

Thanks for the above! I missed it before and have been using an old black sock. Is that an issue?

The reason is ask is that, my chorinator is not maintaining chlorine levels. Wednesday at 9am chlorine at 9ppm. By Friday night, chlorine has dropped to 5.5ppm. This is with the chlorinator at 6/8 (Ie 75%) and operating for 12 hours so I would think that the chlorinator should keep up with normal chlorine loss…. During the ONCT I was only losing 0.5 say 1.5ppm in 24 hours with no chlorinator. So to lose 3.5 in 60 hours with the chlorinator at 75% seems to be something not right.

I have just upped the chlorinator to 100% and will leave on overnight to see if that will boost chlorine levels. I also still have the black sock slowly releasing the CYA in the skimmer.

 

[Texas Splash]

Well, ideally we like to see our SWGs maintain the FC level as desired. Sometimes that changes due to algae, heavy swimmer's load, technical issues, or something else. I'd keep an eye on it for sure. If you continue to lose an unusual amount of FC, I would start with another Overnight Chlorine Loss Test. That's always step #1 since it costs nothing but a little of your time. Once you ensure algae/organics is not an issue, then you can start to look at other potential factors.

 

[Karlosw]

Well, ideally we like to see our SWGs maintain the FC level as desired. Sometimes that changes due to algae, heavy swimmer's load, technical issues, or something else. I'd keep an eye on it for sure. If you continue to lose an unusual amount of FC, I would start with another Overnight Chlorine Loss Test. That's always step #1 since it costs nothing but a little of your time. Once you ensure algae/organics is not an issue, then you can start to look at other potential factors.

I did an OCLT with a loss of 2.5ppm (6.5 to 4). I also have added 2kg of CYA yet stabilizer over the last week yet CYA level has not shifted since testing a week ago.

Since completing the last slam, the only change is to add the CYA and some calcium. Maybe two swims at most. Pool crystal clear as it was through the last slam.

I’m a bit of a loss as the slam I completed was the third in two months.

 

[mgtfp]

Something must be off with your CYA testing. Adding 2kg raises your CYA by 36ppm - this must be visible, assuming that it has all dissolved by now. I suspect that your CYA is actually much higher and therefore your FC/CYA not high enough, which is why you don't manage to get this algae under control.

The CYA sold in Australia comes as a very fine powder, unlike the granules our friends from the US get. This powder clumps up into pretty solid bricks when getting wet, and takes then ages to dissolve. From my experience is is best to knead the CYA filled sock (I use an old sports sock) thoroughly while submerging into the water, like that you avoid the clumping up. I tie the sock to a stick and hang it in front of a return jet. If I want to speed the process up, I drag the sock with the stick around the pool - like that the powder leaves the sock pretty quickly. Afterwards, I distribute any powder that landed undissolved on the bottom of the pool with the brush. Like that, the CYA dissolves very quickly and I usually see the expected increase within a few hours.

 

[Mdragger88]

I did an OCLT with a loss of 2.5ppm (6.5 to 4). I also have added 2kg of CYA yet stabilizer over the last week yet CYA level has not shifted since testing a week ago.

Since completing the last slam, the only change is to add the CYA and some calcium. Maybe two swims at most. Pool crystal clear as it was through the last slam.

I’m a bit of a loss as the slam I completed was the third in two months.

How old is your cya reagent? It’s generally pretty stable but it does get old.
When I got my last refill I was surprised to learn that my cya was higher than I thought & had been measuring with my older reagent.

 

[Newdude]

Is there anywhere that algae could be hiding in plain sight ? Ladder rails, light niches, autofills, the foam on the back of the skimmer door, etc etc etc.