Chlorine is disappearing! (again)

[Youfah Mizzum]

Some of you might recall the saga this time last year from this thread

Chlorine is disappearing!

Firstly some background information: Location: Sydney, Australia (well, just an hour north near Gosford) Pool volume: 22,000 L (4850 gallons) Salt water chlorinator Pool cover mostly kept on except when swimming No opening/closing routine for winter/summer. Coldest it gets here is around 5...

www.troublefreepool.com

Well, same thing now! Although this time we haven't had any particularly significant weather event which could remotely be determined as the trigger.

Quick summary, for some unknown reason my SWCG is not keeping up with regular sanitization and I'm finding each time I test FC, its quite low, like 1. I am barely keeping a possible algae bloom at bay although the water is lovely & clean - albeit slightly hazy - also indicative I understand of low FC levels.

Backwashed filter, then did a OCLT last night, and yes it went from 9 to 6.5.
Currently doing SLAM. Have scrubbed the walls, skimmer box, flappy door. Everything looks clean.
CYA is currently quite low at about 35. Yes, I recognize this needs upping but whilst doing a SLAM I'll keep it around here just to reduce required quantity of chlorine. Some of you might also recall that I've always needed to add cyanuric acid, probs about 0.5 to 1 cup of powder a week. It was only during the prior thread that I realized that is somewhat unusual, despite it being a standard pool maintenance procedure for me. Never known my CYA to be stable over a period of a few weeks. Not sure if that is relevant or not.

I don't think I really need advice as I got plenty of that in my older thread, I guess this is just a rant that it's happening again for no apparent reason.

It might just be that I need to top up chlorine with a manual addition each week or so. If so, so be it. But it shouldn't be.

 

[Bperry]

Some of you might recall the saga this time last year from this thread

Chlorine is disappearing!

Firstly some background information: Location: Sydney, Australia (well, just an hour north near Gosford) Pool volume: 22,000 L (4850 gallons) Salt water chlorinator Pool cover mostly kept on except when swimming No opening/closing routine for winter/summer. Coldest it gets here is around 5...

www.troublefreepool.com

Well, same thing now! Although this time we haven't had any particularly significant weather event which could remotely be determined as the trigger.

Quick summary, for some unknown reason my SWCG is not keeping up with regular sanitization and I'm finding each time I test FC, its quite low, like 1. I am barely keeping a possible algae bloom at bay although the water is lovely & clean - albeit slightly hazy - also indicative I understand of low FC levels.

Backwashed filter, then did a OCLT last night, and yes it went from 9 to 6.5.
Currently doing SLAM. Have scrubbed the walls, skimmer box, flappy door. Everything looks clean.
CYA is currently quite low at about 35. Yes, I recognize this needs upping but whilst doing a SLAM I'll keep it around here just to reduce required quantity of chlorine. Some of you might also recall that I've always needed to add cyanuric acid, probs about 0.5 to 1 cup of powder a week. It was only during the prior thread that I realized that is somewhat unusual, despite it being a standard pool maintenance procedure for me. Never known my CYA to be stable over a period of a few weeks. Not sure if that is relevant or not.

I don't think I really need advice as I got plenty of that in my older thread, I guess this is just a rant that it's happening again for no apparent reason.

It might just be that I need to top up chlorine with a manual addition each week or so. If so, so be it. But it shouldn't be.

If algae is growing, it means the water hasn’t had enough chlorine in it. Probably need to raise it up.

Your CYA is either 30 or 40 so just chlorinate appropriately for whichever it is.

 

[proavia]

Post a full set of current test results from one of the recommended test kits -
Clear Choice Labs for those down under.

Add those results to PoolMath
I see your PoolMath logs are shared to the forum, but there are only chemical additions and no test results for the past year.

If your CYA result is more than 30 and less than 40, round up to 40. Dose FC for CYA 40.

Add your test kit to your signature.

 

[Newdude]

it's happening again for no apparent reason.

The apparent reason is the FC dipped too low and now you have algae.

With 2 seasons in a row, your pool is telling you that your preferred targets are too low.

With a SWG usually chugging along without issue, it is easier to get lax with testing. How often do you test ? With the season peaking for you soon, you simply missed an adjustment when the daily demand increased, or you were cutting it too close and a particularly high UV day(s) hit, leaving you unsanitary.

A great many of us 'run hot' for this exact reason. Whether it's a high UV day(s), a weather event or an impromptu get together, we're covered before it happens. SLAM FC is safe for swimmers and equipment. Look how much leeway you have above target range, and how little you have below it.



So many of us aim a little above target, and when the daily loss happens, fall back into range. If you're losing 4ppm a day right now, a '6 or 7' may not cut it, although both are in range.

Also always factor timing with your tests. The sun depletes FC and the SWG puts it back slowly. If you test an OK level at the low FC part of the day, it will seem fine but might not be after the loss. So it's easy to be fooled. You want your low point to be free and clear of min at all times.

 

[Youfah Mizzum]

Add those results to PoolMath
I see your PoolMath logs are shared to the forum, but there are only chemical additions and notestresults for the past year.

Am I wrong or does posting PoolMath logs require a paid subscription? I just have the free version. EDIT: just worked out how to do it.

Results:
CYA: 40
TA: 75
CH: 400
Ph: 7.6 - 7.8 (I find it hard to distinguish. Nothing wrong with my eyes, I just find the color graduations difficult to determine)
FC: Currently around 14 as doing SLAM

Now that I've worked out how to add my test results I'll keep them updated more regularly

 

[Newdude]

You need the paid subscription ($8/year) to save multiple logs. It's worth every measly penny to have TFP see your history when needed. We can spot where it went wrong, or stop it before it does.

 

[Youfah Mizzum]

you simply missed an adjustment when the daily demand increased

That's great @Newdude . I think you might have struck the answer - it seems so obvious now you mention it. My testing is weekly during summer but in the lead up, like October & the first week or two of Nov, maybe only fortnightly but I'm typically within range, possibly the lower end of normal in which case I increase the generation of my SWCG. But it might not have been enough, or maybe should've supplemented with a litre or so of liquid chlorine (pretty sure you USA folks call it bleach 12.5%). Oh well, too late now.

Last year tapering off the SLAM was such a lengthy process it remained quite high until Autumn and we were no longer swimming.

Anyway last nights OCLT showed a loss of 3 ppm.
Continuing SLAM today

And looks like I was correct with the PoolMath subscription model. I could add 1 set of results but that's it.
I need to pay. And pay I will as it's a nice little tool

 

[Newdude]

My testing is weekly during summer but in the lead up, like October & the first week or two of Nov, maybe only fortnightly

SWGs are *amazing* and they allow this to be possible. But 7 to 14 days is a long time for the FC to dip, then correct itself with you none the wiser at test time. Occasionally it goes south, and it's no surprise why it did. Because SWGs are so amazing you only tested 3 times this month.

The closer the FC is to min, the more you have to pay attention. In the 10+ I run, I have 3+ days of reserve FC anytime I test so there are less days to question.

 

[Youfah Mizzum]

And herein is why I often don't subscribe to software.
I upgraded to Premium but PoolMath is not recognizing I've upgraded. Grrrr. Payment has gone through but nothing has changed in the software features. 'Restore Subscription' button says 'No Subscription Found. Sorry we couldn't find a valid subscription.'
Frustrating. (Sorry, bit of a digression from thread topic).

 

[mknauss]

And herein is why I often don't subscribe to software.
I upgraded to Premium but PoolMath is not recognizing I've upgraded. Grrrr. Payment has gone through but nothing has changed in the software features. 'Restore Subscription' button says 'No Subscription Found. Sorry we couldn't find a valid subscription.'
Frustrating. (Sorry, bit of a digression from thread topic).

PoolMath Subscription not Working - Further Reading

www.troublefreepool.com

 

[Newdude]

They're dealing with a nearly infinite combo of devices, OS's and update #s, and sometimes glitches happen. Follow the steps in above link and they'll make it right.

 

[Mdragger88]

Slam on!
In the future, When the daily demand increases you should do both-
*Add liquid chlorine to get in target range or a scootch higher
&
*increase the output of your swcg.
Swcg’s are great maintainers but not so great as “maker uppers” as they simply take too long & nasties can proliferate in the meantime even if they are oversized.
Along with increasing your fc testing frequency to at least Every couple days in the swim/peak season.
Frequent fc testing allows you to catch a problem before it festers (proactive) vs simply being reactive a week after there was actually a problem.
It only takes a couple minutes but prevents a week or more of your time & $$ slamming .
-the rest of the tests can wait for the weekend or whatever your regular day is.
One other tip is to check the weather forecast! I look at the extended forecast & then kinda make my plan on when to dial up the output in advance of a particularly hot/sunny spell etc.
be sure to find the #/day output of your swcg cell so you can use poolmath effects of adding to help you determine appropriate run times & % to achieve the average 1-5 ppm fc that may be needed depending upon the seasonal conditions.
Edit: it looks like your unit is capable of producing
15grams/hr = 360 grams/day = 0.793664 lbs/day
Save this info in your poolmath settings as your model is not listed in the options.

 

[Youfah Mizzum]

Last night OCLT showed another loss of 3 ppm.
Continuing SLAM today

Seems odd doing it when the pool, skimmer box and anything I can see is stunningly crystal clear. Today will be the 3rd day of SLAMming.

If tonights OCLT still shows loss I'm just going to have to resign myself to the fact that I need to top up the SWG with liquid chlorine. I'd rather know that I need to chuck in a litre or so of liquid chlorine every few days than have to go through the constant monitoring during SLAM with no improvement.

I know the advice here will be to continue SLAM but I would expect to see some improvement during OCLT and like I said, the pool is looking fabulous. Maintaining a high FC level is much easier than constantly SLAMming.

 

[Bperry]

Last night OCLT showed another loss of 3 ppm.
Continuing SLAM today

Seems odd doing it when the pool, skimmer box and anything I can see is stunningly crystal clear. Today will be the 3rd day of SLAMming.

If tonights OCLT still shows loss I'm just going to have to resign myself to the fact that I need to top up the SWG with liquid chlorine. I'd rather know that I need to chuck in a litre or so of liquid chlorine every few days than have to go through the constant monitoring during SLAM with no improvement.

I know the advice here will be to continue SLAM but I would expect to see some improvement during OCLT and like I said, the pool is looking fabulous. Maintaining a high FC level is much easier than constantly SLAMming.

You’de help yourself if you logged your test results more often. It helps you spot why problems might be occuring.

 

[Youfah Mizzum]

You’de help yourself if you logged your test results more often.

Well, I would if I could

A little over 24 hours ago I upgraded from the free PoolMath to Premium with a $10.99 (AUD) but the @#$%^& software didn't recognize I had upgraded.
It's only been the last couple of hours since I tried to Restore Subscription for the thousandth time that it finally succeeded.
Bottom line - I have only had the subscribed version of PoolMath for about 2 hours.

From now on, I'll be logging all tests & additions.

 

[Bperry]

Well, I would if I could

A little over 24 hours ago I upgraded from the free PoolMath to Premium with a $10.99 (AUD) but the @#$%^& software didn't recognize I had upgraded.
It's only been the last couple of hours since I tried to Restore Subscription for the thousandth time that it finally succeeded.
Bottom line - I have only had the subscribed version of PoolMath for about 2 hours.

From now on, I'll be logging all tests & additions.

 

[Mdragger88]

Refresh my memory, do you have lights or water features?
Crystal clear water & such a high oclt loss points to hidden algae.
Remember that the
SLAM Process involves more than just raising & maintaining the fc level. You must also be sure to do all the things

*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.
Foregoing these tasks can make things drag on.

Btw,
If my math equation above is correct Your swcg is plenty capable of adequately chlorinating your pool on even the highest demand days & has the potential to produce 16ppm fc per day if run at full till around the clock. I don’t really suggest you do that but you shouldn’t need supplementation to run at high target or a scootch above as we suggest.

P.S.
I see your logs!

 

[Newdude]

Seems odd doing it when the pool, skimmer box and anything I can see is stunningly crystal clear

Algae is microscopic, but grows exponentially. The last couple of growth cycles is the difference between clear water algae and full blown swamp. The TFP ways will give you plenty of warning while you still have the upper hand.

Once it goes green, it's a runaway train which will be a miserable battle with your warm weather.

 

[Youfah Mizzum]

After 3 days of SLAM I can report that last nights OCLT reported nil loss

Now that I have the upper hand I'll have the SWG generating sufficiently to maintain a chlorine level at the upper end of the recommended range.
Currently at 11 so the post-SLAM taper is gonna be slow.

Appreciate everyone's encouragement.

 

[Newdude]

Pretty soon (like a week and a half) the days will start getting shorter for you and the sun will slowly get lower in the sky in the southern hemisphere. When you miss an adjustment in the back half of the season, you make more FC than you needed and it's a GREAT problem to have. You'll find the FC in the teens and the water will be STUPID clear.

It'll still take a while to taper off but think of the whole season UV loss like a bell curve. Your FC loss is next to nothing at the ends and is the highest mid season. No matter where you live, you can expect loss to more or less follow the pattern year over year.