Too much chlorine loss or no?

[MontereyofSunshine]

Here’s the saga-

Mustard algae started about a month ago, despite my chemicals being consistently balanced (yes, they were balanced - please don’t tell me it’s because something was off bc I test daily with a tf pro).

Here’s where I’m at (at the rec of our pool guy. I DO trust him).

Messed with shocking. Didn’t help. Mustard kept coming back. (No - at this point I did not see TFP’s advice on slamming then mustard slamming).

Pool guy suggested copper based algaecide - that he’s seeing tons of mustard algae in our area given the heat waves with excessive torrential downpours, even in balanced pools.
Tfp pro test kit.

(Note: CC <.5 = it took one drop of R-0871 to get rid of the tiniest tinge of pink after adding R-0003)

Specs: 22,500g chlorine plaster in ground pool. Temps in the mid 90’s. Rain almost everyday if not every other day right now - short times but tons of rain in that amount of time. Liquid chlorine. Only pucks in floater if rain/drain some/cya lowers.

7/19: 11:14pm: FC 15 CC <.5 PH 7.6

7/20: 11am: copper based algaecide. Run filter 24/7. Brushed the Crud out of it. FC 16 CC <.5 PH 7.5 Alk 100 CYA 40. Phosphates ~1300 (dealt with this later see below). Brushed 3x.

7/21: brushed 2x, major rain overnight

7/22: 9:49am: FC 1 CC <.5 PH 7.5 Alk 100 CYA 40. Brushed 2x. Added 4gal of 12.5% liquid chlorine. 10pm: FC 14.0 CC <.5

7/23: vacuumed, backwashed

7/24: 10pm: FC 7.5 CC <.5 PH 7.5 Alk 90 CYA 40.

7/25: brushed. 8:13am: FC 7.5 PH 7.5 *passed OCLT* 8:30am: added phosphate remover. 3pm: torrential downpour. Added 1gal 12.5% liquid chlorine to get ahead of it. 10:45pm: FC: 12.5 CC <.5 PH 7.8

7/26: 9:45am: FC: 10.0 CC: 0 (first time in a while but it comes back) PH: 7.8 Alk: 100 CYA: 40 11:30pm: FC 7.5 CC: <.5 (came back). PH: 7.8 *shocked: 3lbs of 73% cal hypo*

What do you make of the chlorine loss and <.5 cc consistently?

Thoughts? Something brewing or keep on keeping on?

 

[Newdude]

Mustard algae started about a month ago, despite my chemicals being consistently balanced (yes, they were balanced - please don’t tell me it’s because something was off bc I test daily with a tf pro).

If you have algae, your FC was too low for your CYA level. You can test it 62 times a day and that doesn't change the simple fact. There are no two ways about it.

Something brewing

If you lose FC overnight with no UV or bather load, it's organics. But you've also been adding things around the same time so it's remotely possible that the test was skewed.

Do another OCLT with no interference from anything else. Because of the likeliness of something brewing, bring it to SLAM now and do your best to maintain 40% of your CYA level until the OCLT. If you lose more than 1ppm overnight, (I'd slam personally if you lost *1*), then SLAM Process

 

[JJ_Tex]

I'm seeing talk of phosphates, algaecides, pool guys, I also assume there is a pool store in the mix as well. Typically people get really frustrated when they mix and match advice and techniques. The TFP recommendation for algae is SLAM, which includes no pool stores, algaecides, pool guys, cal-hypo, etc. The only thing you need for the SLAM is a good test kit, lots of liquid chlorine, some elbow grease and patience.

 

[MontereyofSunshine]

If you have algae, your FC was too low for your CYA level. You can test it 62 times a day and that doesn't change the simple fact. There are no two ways about it.

If you lose FC overnight with no UV or bather load, it's organics. But you've also been adding things around the same time so it's remotely possible that the test was skewed.

Do another OCLT with no interference from anything else. Because of the likeliness of something brewing, bring it to SLAM now and do your best to maintain 40% of your CYA level until the OCLT. If you lose more than 1ppm overnight, (I'd slam personally if you lost *1*), then SLAM Process

Thanks for the help and fairly judgment free response!

 

[MontereyofSunshine]

Thanks for the help and fairly judgment free response!

Questions: I’m going to slam it. I used cal hypo last night. Can i switch to maintaining with liquid chlorine?

 

[JJ_Tex]

Questions: I’m going to slam it. I used cal hypo last night. Can i switch to maintaining with liquid chlorine?

Yes, you can easily switch to liquid chlorine which is preferred.

The only concern with mixing and matching chlorine is when you are storing or putting them in a chlorinator or other enclosed space. The various types of chlorine can interact and even cause explosions. Once in your pool water, there are no worries with mixing and matching.

 

[Newdude]

Can i switch to maintaining with liquid chlorine

Yup. It's preferred because it only raises your FC so you don't have to pay attention to the CH rising. Also, large additions of cal-hypo may cause cloudiness making things appear worse for a spell.

Once any form of chlorine is in the water, it can be mixed with other forms. Never ever mix different forms of chlorine outside of the pool. We had 2 explosions yesterday. I had a buddy create an explosion by tossing tabs in an old calhypo bucket. The residual dust which wasn't even apparent was enough to make it happen.

 

[MontereyofSunshine]

Yup. It's preferred because it only raises your FC so you don't have to pay attention to the CH rising. Also, large additions of cal-hypo may cause cloudiness making things appear worse for a spell.

Once any form of chlorine is in the water, it can be mixed with other forms. Never ever mix different forms of chlorine outside of the pool. We had 2 explosions yesterday. I had a buddy create an explosion by tossing tabs in an old calhypo bucket. The residual dust which wasn't even apparent was enough to make it happen.

For sure. Thanks for the safety tip. Lastly - my Ph this morning is 8.2. I haven’t had to adjust it during a slam. Where does muriatic acid play a part here? Or - wait until the slam is over and don’t worry about it? Slam for me is 16, currently FC is at 18 with 0 CC so I’m there. Add acid now, or wait? (I searched around on here for “adding acid with high chlorine levels/during slam but can’t find anything).

 

[JJ_Tex]

pH testing will show higher than reality when you are slamming. Do you know your pH reading before the SLAM? Step 1 in the SLAM process is to lower your pH to 7.2. If you know your prior reading add enough acid to knock your pH down from the old reading to 7.4. Then you only worry about testing FC until you think you have crystal clear water and are ready to see if you pass all 3 criteria to end the SLAM.

 

[MontereyofSunshine]

pH testing will show higher than reality when you are slamming. Do you know your pH reading before the SLAM? Step 1 in the SLAM process is to lower your pH to 7.2. If you know your prior reading add enough acid to knock your pH down from the old reading to 7.4. Then you only worry about testing FC until you think you have crystal clear water and are ready to see if you pass all 3 criteria to end the SLAM.

Thanks

 

[MontereyofSunshine]

Thanks

Yup. It's preferred because it only raises your FC so you don't have to pay attention to the CH rising. Also, large additions of cal-hypo may cause cloudiness making things appear worse for a spell.

Once any form of chlorine is in the water, it can be mixed with other forms. Never ever mix different forms of chlorine outside of the pool. We had 2 explosions yesterday. I had a buddy create an explosion by tossing tabs in an old calhypo bucket. The residual dust which wasn't even apparent was enough to make it happen.

Hey newdude! You seem really helpful and also not condescending. Thought I might update you-

My slam level is 16.

Yesterday at 7:30pm, my fc = 12.5. Added 2 gallons to presumably bring it up to 23.5 (we were potentially getting canned w rain). “Effects of adding” on poolmath app is generally spot on by about 1ppm.

This morning: fc = 21.5 (8:30am or so - no sun on pool yet). 0 cc.

4pm: fc = 20, 0 cc.

8:30pm: fc = 15.5, <.5cc (something read, but one drop made it clear again). Added 1 gallon (effects of adding: fc +5.6).

What does this tell you? Why would cc teter totter? Why would I lose 6ppm - is that possible due to just sun? Asking for future reference - I’m having a hard time, aside from all this, understanding what normal daily chlorine loss would be.

Also - if, for example, I have to add chlorine at night to keep it at slam levels, how do i do an oclt without a starting number? Is that a wait until the next day, or wait until I don’t have to add any, or….

Appreciate your thinking.

 

[Newdude]

What does this tell you? Why would cc teter totter? Why would I lose 6ppm

SLAM doesn't always go in a linear direction. Sometimes it's 2 steps forward and one back.

Did you brush today? That exposes wall algae that grew a biofilm to protect itself. Then it needed killing.

I’m having a hard time, aside from all this, understanding what normal daily chlorine loss would be.

That's easy peasy. Think of a bell curve. At either side of the season, FC loss is minimal and it shoots up for the middle part of the season. So you can expect 2 ppm loss in the early/late season, (1 or less if you extend a good deal), and you can expect 4 ppm loss mid season. It's not perfect like that and some days/weeks fall out of character either high or low, but overall it's like that.

Your frequent testing will be your guide, and ironically, a little effort saves a truck ton of effort. By testing regularly, you'll just know you've been losing 3.5 ppm a day the last two weeks (etc). You'll then dose tomorrow like today because it'll likely be similar. As the season winds down, daily UV loss will slowly decrease like it increased in the spring.

, I have to add chlorine at night to keep it at slam levels, how do i do an oclt without a starting number?

You add, mix for 30 mins, and test to get your actual start #. Effects of adding is great and fine for regular SLAM dosing, but if you fail the OCLT you have to wake up early at least one more time. Lol.

 

[MontereyofSunshine]

You’re so incredibly helpful thank you. I can’t figure out how to reply to individual comment chunks like you so here’s my response.

Re: brushing. Makes complete sense. My partner went out for that 4pm chunk and brushed.

Re: chlorine loss in sun - makes sense. Thanks.

Re: adding chlorine to slam - that’s what I couldn't find. How long after adding so I need to wait and circulate before testing.

Heading out now to give it a test and brush! Mind if I keep you posted?

 

[MontereyofSunshine]

SLAM doesn't always go in a linear direction. Sometimes it's 2 steps forward and one back.

Did you brush today? That exposes wall algae that grew a biofilm to protect itself. Then it needed killing.

That's easy peasy. Think of a bell curve. At either side of the season, FC loss is minimal and it shoots up for the middle part of the season. So you can expect 2 ppm loss in the early/late season, (1 or less if you extend a good deal), and you can expect 4 ppm loss mid season. It's not perfect like that and some days/weeks fall out of character either high or low, but overall it's like that.

Your frequent testing will be your guide, and ironically, a little effort saves a truck ton of effort. By testing regularly, you'll just know you've been losing 3.5 ppm a day the last two weeks (etc). You'll then dose tomorrow like today because it'll likely be similar. As the season winds down, daily UV loss will slowly decrease like it increased in the spring.

You add, mix for 30 mins, and test to get your actual start #. Effects of adding is great and fine for regular SLAM dosing, but if you fail the OCLT you have to wake up early at least one more time. Lol.

This morning:

 

[Newdude]

adding chlorine to slam - that’s what I couldn't find. How long after adding so I need to wait and circulate before testing.

30 mins mixing is plenty.

Also, we round CYA up to the next 10, if it's not the last 10.

 

[MontereyofSunshine]

30 mins mixing is plenty.

Also, we round CYA up to the next 10, if it's not the last 10.

Oh interesting. I didn’t know that. I’ve been going off of 40 for the purposes of slam levels.

Thanks again. Keeping on keeping on

 

[Newdude]

I’ve been going off of 40 for the purposes of slam levels

Then alls well that ends well. Lol.

I went 6 or so years choosing the right choices by dumb luck. Sometimes you get lucky.

 

[MontereyofSunshine]

Had 0 CC all day yesterday (tested 3x), no signs of algae (dead or alive), passed the OCLT. Raised it up this morning to mustard shock levels, tested just in case to make sure. Dumped all of our equipment into the shallow end. Fingers crossed.

After this - let the sun do the work on lowering chlorine back down? Continue a solid brush routine. And - at what point do my other tests become reliable again? (Ph, alk)

 

[Newdude]

After this - let the sun do the work on lowering chlorine back down?

Yup. It'll go quick at first and then slow as the FC gets closer to target levels. It takes what it takes and there's no rush.

And - at what point do my other tests become reliable again? (Ph, alk)

Ph is good under 10 FC. The rest won't matter from the FC being elevated, we just don't have people mess with them during slam because none of them are short term issues.

Post up a full set if #s once the FC is below 10. We'll go from there.

 

[MontereyofSunshine]

Solid. Will keep an eye on the chlorine. Tested twice today and added a little jussssst to make sure I don’t approach my mustard slam level. Thanks for the tip on it going quickly in the beginning then slowing down on loss - I would have definitely had a meltdown thinking I had an issue. We brushed already today. Will brush again tonight.

We are hosting a bridal shower Saturday. The hope is we can swim for the “after party.” It’s hot as Darn here and the pool gets smacked with sun from about 9:30am-6:30pm, so if I get lucky, we can swim Saturday. If not, oh well.

Thanks for being so kind.