High Chlorine After Shock
- Thread starter kcassidy0772
- Start date
A little surprises this morning. Remember when I started this last Wednesday, I overstocked my pool with Powder shock because I had yellow algae. My pool immediately got so cloudy you couldn’t see the bottom of the pool until about Sunday. Each day after a little better. (See pics posted last night). Although still “milky-cloudy”, I saw no signs of yellow algae on bottom of pool anymore. And I have spent so much time staring real hard looking for it. So, I come out of house this morning and it’s all over the bottom of pool again. Could this have developed just overnight, or was it more likely there all this time and only now am able to see any of it? I’d be surprised, bc right up until last night I didn’t see anything at all. Did same thing last night and just added 5ppm chlorine so I wouldn’t expect much change. I’ve attached a pic of the algae. Am I right this is yellow algae? When you touch it with a brush it shoots up in like smoke, so that’s why I knew it wasn’t dirt. I didn’t go in the pool this morning, but it looks exactly like what I had before. Here is pic this morning.
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It could just as easily be pollen / farm dust / environmental debris here. I have flowers and bushes popping all over finally, and the farm next door is in full swing.
The Overnight Chlorine Loss Test will let you know if its algae.
The Overnight Chlorine Loss Test will let you know if its algae.
I have another question. I probably won’t be ready to start SLAM until tomorrow since I won’t be applying Muriatic Acid until later tonight. I know I’ll have to test again before I start. But if my CYA stays at 70, and FC at 13.5, should I bring that CYA level down too before I started SLAM? If I’m correct, at those levels I would need to add about 188.5 ounces of shock. (10,000 gallon pool)
- Jun 1, 2018
- 16,027
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
SLAM target is 40% of the CYA. So it's 12 FC for 30 CYA or 28 FC for 70 CYA.
With cheap and pool friendly pool water here, I'd drain 60%
- Jun 1, 2018
- 16,027
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
A lower cya level does make the
SLAM Process a bit easier to accomplish.
The recommendation for manually dosed pools is to have cya between 30-60. I would recommend that you get it down to 40. Which means exchanging about 40% of your water.
It looks like you may have your pool volume off a little unless you have a shallow & a deep end
The slam process involves not only raising fc to shock/slam level for your cya initially but also keeping it there by testing & replenishing it often until you pass all 3 end of slam criteria.
This requires alot of liquid chlorine as it can take a week or more.
Decoy205
Silver Supporter
Regarding the filter cleaning, you should only clean it when the pressure increases 25% of clean pressure. With cartridges my understanding is that they work better a little dirtier for catching smaller particles.
Don’t clean it every night clean when pressure goes up.
Don’t clean it every night clean when pressure goes up.
Interesting. I didn’t see a calculator in the pool math app. But when I research online the formula it gives is LxWxD multiplied by 5.9. Which came out to 10,620. I round down to 10,000 because my pool water depth is only about 46 inches. No deep/shallow end. Am I using a wrong factor with the 5.9?
- May 3, 2014
- 62,717
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Not in the app. Old Poolmath Webpage. Linked at bottom of every page.
PoolMath
Discover the calculator behind the perfect pool, PoolMath. Dealing with pools has allowed TFP to become the original authors of the best calculator on the net.
www.troublefreepool.com
I’ve run it to an issue where I can’t drain the pool right now like I hoped. So I’d I wait to drain the pool I probably won’t be able to start slam until late next week. So, what are all the drawbacks if I slam now with the CYA high? BTW, I retested the CYA tonight and I say it’s more like 60. More confident in tonight’s test than yesterdays.
That's great that you're feeling better about it, but you really want overhead sun for the test.
SLAM. Target FC is 40% of CYA.
FC burns off as a %, and as such, burns off faster at higher levels. It's not noticeable in normal range for the most part but becomes noticeable at 20+. So everyday you'll lose your regular UV loss, plus the extra associated with the higher FC, plus whatever went to killing algae.
Having a smaller pool will help considerably and if you 'waste' 5 extra gallons to UV, you probably won't lose your house.
Your call if you'd rather limp along adding 5ppm a day to stop it from getting worse, or start the process now.
I actually did the test outside about an hour ago, not in direct sun but still complete daylight. Last night I did the test in my dining room. That’s why I retested tonight bc I was reading today that it should be done outside. So, if I leave CYA as is and start the slam, I will eventually have to drain though because the CYA isn’t good to be that high normally no?
*overhead sun* is best.
Mid day. I know. I know. I'm not around at lunch either. It is what it is. Get a good confirmation over the weekend or your earliest sunny day off. Use 60 and it probably will be close enough for now.
A 60 is totally manageable, with higher targets. I'm at 70 local to you and it works great when things are well. If either of us has to SLAM, it'll only hurt us then. Again, with a smaller pool it'll hurt you 3X less than me with 34k gallons.
Awesome, thanks for all the info. I’m actually home about 2 tomorrow (summer Friday’s!). So I’ll retest then.*overhead sun* is best.
Mid day. I know. I know. I'm not around at lunch either. It is what it is. Get a good confirmation over the weekend or your earliest sunny day off. Use 60 and it probably will be close enough for now.
A 60 is totally manageable, with higher targets. I'm at 70 local to you and it works great when things are well. If either of us has to SLAM, it'll only hurt us then. Again, with a smaller pool it'll hurt you 3X less than me with 34k gallons.
Looks like I’m ready to SLAM. Pool has already improved a lot so hoping this won’t be too long. For last week just been adding 5ppm a day and brushing. Right now I would say about 85% clear. Just tested again to confirm my levels. CYA is 60, FC is 15ppm, and CC is zero. Only thing I’m waiting for PH to come down a little more. Not quite down to 7.2 so I added another 17 ounces of MA. I read that often the MA you buy in a lot of these stores is diluted and not the strength you’d expect. No biggie. One question I do have, is that since I’ve only been adding 5ppm of chlorine a day now for a week, what can cause my FC to be so much higher than what I’ve been putting in? And I haven’t had any other chlorine in the pool, took the pucks out once I started with the liquid last Saturday.
JupiterFL
Silver Supporter
- Mar 28, 2023
- 128
- Pool Size
- 12638
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I will let the experts continue to help, but since time could be of the essence for this comment, the PH test is not valid for FC over 10. I don't know what steps you should take first, but don't add anymore acid until you get guidance.
The common brand at the Home Centers went 'trade secret 10% to 30%' on its MDSD. Likely to hide the fact its half strength.
Look for any half strength (14%) buzz words like 'low/no fumes', 'green' or 'Eco'. You'll need twice as much but other than that, it's still good.
I just needed some recently and the Blue/Orange stores only had 'low fume' for $12, so I ran over to Sherman Williams (paint stores carry it) and they had full strength but it was $25.
Ace Hardware had full strength for $9.99
That's 35ppm, minus daily UV loss and whatever went to algae. So you lost 20 and have 15 left.
GREAT catch.
What is it testing now ? (Although it may be skewed higher than it is due to 10+ FC)
Still right around 7.5 right before I added like an hour ago.The common brand at the Home Centers went 'trade secret 10% to 30%' on its MDSD. Likely to hide the fact its half strength.
Look for any half strength (14%) buzz words like 'low/no fumes', 'green' or 'Eco'. You'll need twice as much but other than that, it's still good.
I just needed some recently and the Blue/Orange stores only had 'low fume' for $12, so I ran over to Sherman Williams (paint stores carry it) and they had full strength but it was $25.
Ace Hardware had full strength for $9.99
That's 35ppm, minus daily UV loss and whatever went to algae. So you lost 20 and have 15 left.
GREAT catch.
What is it testing now ? (Although it may be skewed higher than it is due to 10+ FC)