algae bloom - shocking

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swimmingfool

swimmingfool

0
Nov 12, 2010
46
Nokomis, Florida
LONG STORY short: we have neglected our pool through the winter when an urgent home ER surfaced. It remained clear up until a couple of weeks ago. -obviously as soon as the weather starting warming up the algae kicked in. Instead of getting out the testing kit I bought- my husband (on his day off :hammer: )decided to go to the pool store and have the water tested-purchased the stuff they told him to use-and started a shock treatment. **** SWG was removed/stolen so we are using the tablet chlorinator now.
here are the numbers we started with on 03/01
TC 0
FC 0
CC 0
PH 8
TA 120
CH 375
CYA 100
TDS 3700
temp was 69
langlier index 0.6
mustard Algae moderate

per their instructions:
My husband added 2 tablets to the tablet chlorinator
6 cups muriatic acid
1/2 hour later he added 2 1/2 gallons of 10.5% liquid chlrine
1/2 hr later 1 bag of stop yellow
Wed. he added 1 1/4 gallons of 10.5% liquid chlorine as instructed by the pool store.
pump has been running non stop.

today I had the chance to get out the kit, take some tests, read over the info here on the site, and plug in the numbers into the calculator.

Numbers now:

FC 7
cc 1
PH 7.2
TA 100
CH 460
CYA 50

If I am reading the chart right - I should add 326 ounces of 10.5 liquid chlorine
43 ounces of Borax.

I am new at using the test kit but I did do some of the tests a couple of times to check my work.
and I just want to make sure I did the chart right

I guess I need a little hand holding my first time! Any help would be appreciated. Oh, and one more question:
It's probably going to make me sound really inexperienced (WHICH I AM!) Is "temp" asking for the water temp or the air temp :oops: ?

thanks in advance!
 
The pool will need chlorine, but ditch the tabs. While they do add some chlorine, they also add CYA. Higher CYA levels mean you need higher chlorine levels to be effective. Liquid chlorine is what you really should use. Ordinary unscented bleach is good if you don't have the 10.5% stuff.

I do not know what kit you are testing with, but if we trust your CYA test over that of the pool store (and I am inclined to do just that), you should raise your FC to 20. This is info from the CYA/Chlorine chart in Pool School - link at top right of page.
With your FC at 7, you need to raise it by 13 to reach 20 to reach shock level. According to the pool calculator http://poolcalculator.com/ , that will take a gallon and a half of 10.5% liquid chlorine, or four 96oz. jugs of 5.25% bleach. You can pour that right in the water in front of a return while the pump is running.
You'll need to reach 20, and maintain 20 by testing and dosing often, as the FC will be consumed by the algae it kills. It can drop pretty quickly in the early stages of an algae battle. Keep the pump circulating.

Once your pool can maintain less than a 1ppm FC drop overnight, you will be done shocking.

Your ph is ok at 7.2, as is your TA at 100. CH seems like it may be a touch high, but I'll let smarter folks than me weigh in on that.
 
Your numbers look pretty good as they are (PH, TA, CH, CYA, etc) I wouldn't touch those until 1) the algae is under control and 2) you feel more comfortable with how all that works (more time in the Pool School). For example - a low PH will help the shocking process so no borax right now.

Right now your pool needs Chlorine to combat the millions of Algae cells growing there. Expect your pool to use a lot of chlorine during this shocking period. Once you've overwhelmed the algae the usage will drop way down.

So bring up to shock level. Test frequently and redose as needed (as much as hourly). Eventually you will have a CC of .5 or less and pass the overnight test (loose less than 1ppm of Chlorine overnight)

One thing I notice - the difference in Pool store results in CH and CYA. CYA doesn't just go from 100 to 50, and CH doesn't just jump up 125ppm. What kind of kit are you using? Pool store's often use strips and then read them on a computer. Sounds technical but it's wildly inaccurate.

It'll all feel overwhelming at the moment. It gets a lot easier.
 
thank you both for your quick responses! I will add the chlorine.
I purchased the trouble free test kit TF-100. that's what I used for my tests. I did the CYA test several times - at noon and again this evening as the sun went down. I got 50 all times. Same with the CH. I don't know why the difference.
 
You've come across the first mind blowing reality of pool ownership - pool store test results are often way off. As is their advice.

It's sad and very confusing for the uninitiated - but it's true.

Be vigilant with the testing/shocking and the pool will clear faster.
 
I don't know why the difference.
Click to expand...
<grin> Oh, we know. That is why we always recommend getting a good kit and doing your own testing. Also why I said that I was inclined to believe your results.

Keep in mind that you will be adding chlorine pretty regularly, especially during the early stages of fighting algae. It will begin going away as soon as you put it in the pool, so you will want to check on it and top it off after each few hours.

There is some good information under Defeating Algae in Pool School.
 
one last question - what does it mean when after I put my heaping scoop of the R-870 powder in the 10mL of pool water - the water remains clear? Can I just add another scoop? I have been discarding the water and starting over. I always get pink water the second time. Just wondering.

And again thanks to those that helped me. My pool is beautiful this morning!
 
Could be one of two things, either your FC is very low and the color change is not noticeable, or the FC is high and you need an extra scoop for the color change to take place. Since you are in the shock process I would say you need that little bit extra for the color change to take place. Put in the powder, swirl the vial a couple of times. If there is no change then add another scoop of powder. If there is still no change run the OTO FC test and that will tell you if there is any FC in the water at all.
 

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