Having Difficulty With No Free Chorine..
(Larchmont, N.Y. )
I have a OVAL 12X 24 = 8334 GALLONS = 7372 CAPACITY pool.
Since July 8, I have been trying to tame this monster.
The water looks crispy clean and all levels appear to be within range.
I have shocked it 5 times, even after heavy rain.
Back washed twice, and vacuumed 4 x's.
Every time I go to the pool store, they advise to shock again.
Last time they sold me super shock-Sodium Hypochlorite solution.
Added some and nothing changed, added some more today and now reading went up to a almost 1.
DATE TIME FILTER PH CHL ALKAL STAB
21 3:00 8hrs 6.8 0 0-40 0-30
22 12:00 5 6.8 0.5 40-80
22 4:30 8 6.8 0.5 40 0
Added turbo shock, 3oz Algaecide, 8oz Sod/Bicarbonate turned pump on again at 5:00 added 16 oz pH plus
22 8:00 +4 7.2 0.5 120 100 ADDED SUPER-SHOCK 8:00 PM AND RAN POOL 2 more HOURS THEN CHECK
22 10:00 +2 6.9 1 120 30-50
Should I add more of the liquid super shocker chlorine?
I am so worried that the summer will go by and I will never get to go into my beautiful pool.
Please help, I am drowning in sweat.
Thanks for your question Jules
I’m going to try to answer your questions in the order of the paragraphs because there’s so much information to cover.
First I would recommend getting a Taylor Reagent FAS-DPD K-2006 pool water test kit. It's the best on the market and the one I used when I did pools in Arizona and now with the YMCA pool.
Water Testing Kit
I appreciate all of your chemical readings.
It must have taken some time in typing those in and you're probably at your wits end with the pool.
I would advise you to keep filtering. In the Summer the pool pump needs to run 10 - 12 hours per day, 4 - 6 hours in the Winter, unless the pool is closed.
Shocking is done to remove the bacteria and organic matter in the pool.
The FAS-DPD kit will have a test for that. It’s called combined chlorine, or chloramines.
You need to shock only when the chloramines level gets above 0.5ppm.
There’s no need to shock a pool on a weekly basis, only when the pool needs it, and that’s why you should do the combined chlorine test with the FAS-DPD kit.
The question doesn’t say what kind of filter you have, but I will assume it’s a sand filter.
You need a little bit of pressure for the sand filter to run properly, about 5psi over the “just backwashed” psi.
Backwash when the pressure gets around 8 – 10psi over the just backwashed pressure.
Sodium Hypochlorite is a good pool chlorine to use.
This liquid chlorine is about 12 – 16% chlorine with a little bit of salt and water mixed in.
You need to do something that not many pool owners do, but it’s very important…Test you tap water with the FAS-DPD kit for total alkalinity, pH level, and calcium hardness.
This way you’ll know what is going into the pool so you can make the right adjustments.
Here in Albany, OR the tap water’s total alkalinity is 30ppm while the pH level is a little higher, about 8.2ppm.
By knowing this I can tell what’s going on with the pool and why
the alkalinity keeps going down. We’re adding about 1000 – 2000 gallons of this water every day, so I know in about 2 – 3 months I’ll need to raise the alkalinity level.
There are no surprises with this.
Every time you go to the pool store they tell you to shock?
Have they mentioned that you might be using an un-stabilized form of chlorine and you need to get some cyanuric acid (CYA) in the water?
This might be the reason your chlorine readings are always so low. You can go here to get the info. you need about CYA:
Swimming Pool Chlorine Tablets
Get a tab floater and keep it full of chlorine tabs. Don’t put them in the skimmer.
The only exception to this is when you’re running the filter 24/7.
You need to get the CYA in the range of 20ppm - 40ppm. This way the chlorine is most effective, but don't let it get out of hand.
Too much CYA and you'll need to drain 1/3 - 1/2 of the pool water, re-fill, and start again.
CYA should be about 7.5% of your chlorine. At 2.5ppm chlorine divided by 7.5% = 0.33.
Keep your CYA around 33ppm. Higher chlorine levels will require a higher CYA reading.
It looks like your pH level and total alkalinity are not too far off. Just a couple of corrections should correct those readings.
With your pH of 6.9ppm, you’ll want to add a little more sodium bicarb. to the pool.
You can also use 20 Mule Team Borax which raises the pH without much happening to the alkalinity.
Swimming Pool pH Levels
Once the pH is about 7.2 – 7.4, which is acceptable, time to decrease the total alkalinity:
Swimming Pool Alkalinity
Muriatic acid is used to lower both the pH and alkalinity, but you need to “tell” the pool which one you want to lower.
The above link will show you how to lower the total alkalinity without much happening to the pH level.
Another way to help raise the pH level is with the link above, and a process called “aeration”.
This is done when the water is moving, splashing, slides and water features on, etc…It’s a “gassing off” of the CO2 (carbon dioxide) which raises the pH level and not much to the alkalinity.
Getting the pH to 7.6 – 7.8ppm and alkalinity to 80 – 100ppm shouldn’t take much effort. But you need patience.
Make an adjustment, allow for one full turnover of the water, probably about 6 – 8 hours in your case, then re-test and make another adjustment if needed.
Once you get the pool chlorine stabilized between 1.5ppm - 3.5ppm and the CYA of 20ppm - 40ppm, there shouldn't be a need for algaecides.
By keeping the chlorine readings at these levels, you'll be killing off any algae anyway, because that's what chlorine does.
Hope this helps and let me know how it turns out for you
All the best and have a great Summer
Follow Up Comment: Drowning in Sweat - Difficulty Raising Chlorine
Date: July 23, 2010
Got alot of homework here.
I am off to the a different pool store with sample of water and prepared to buy what you have suggested.
Will keep you posted, however, expecting rain, Fri. Sat, and Sun.
Thank you and will keep you posted.