pool clean now, how's my chemistry look?

Water bugs, swimming insects and sweat bees.
Foaming bubbly water. Frogs in the pool.
Dead animals in the swimming pool.
mound
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Joined: Wed 09 May, 2007 11:46

pool clean now, how's my chemistry look?

Postby mound » Wed 09 May, 2007 11:53

1.5 weeks ago I took the cover off my inground vinyl lined pool, it was dark and nasty. I used 6% sodium hypochlorite solution (just regular no-frills household bleach) - total of about 9 gallons over a 3 day period, got it up past 15ppm and within 4 days, the water is crystal clear and blue.

I have done nothing else, aside from vacume any remaining junk.

I just did a complete drop-based test, here are my results:

Free CL - 10ppm
Total CL - 10ppm
Combined CL - 0ppm

Total Alkalinity - 120ppm
Ph - 7.2
Calcium Hardness - 140ppm
Cyanuric Acid - ~40ppm (subjective test, somewhere between 30 and 40)

Temp is 67F

I think Calcium may be a bit low, though it is a vinyl pool.

What are your suggestions? I'm surprised the chlorine seems to be staying at 10ppm for the past several sunny days. I would have thought it would drop by now. ??

Everything else looks "good" according to the ideal range listings on the test kit.

I'm just surprised is all, as last year "the pool store", over about 3 weeks and $250 worth of chemicals got me to where I am now after just over a week and less than $20 worth of chemicals!

Thanks
Paul


me_too

Re: pool clean now, how's my chemistry look?

Postby me_too » Wed 09 May, 2007 13:13

mound wrote:1.5 weeks ago I took the cover off my inground vinyl lined pool, it was dark and nasty. I used 6% sodium hypochlorite solution (just regular no-frills household bleach) - total of about 9 gallons over a 3 day period, got it up past 15ppm and within 4 days, the water is crystal clear and blue.

I have done nothing else, aside from vacume any remaining junk.

I just did a complete drop-based test, here are my results:

Free CL - 10ppm
Total CL - 10ppm
Combined CL - 0ppm

Total Alkalinity - 120ppm
Ph - 7.2
Calcium Hardness - 140ppm
Cyanuric Acid - ~40ppm (subjective test, somewhere between 30 and 40)

Temp is 67F

I think Calcium may be a bit low, though it is a vinyl pool.

What are your suggestions? I'm surprised the chlorine seems to be staying at 10ppm for the past several sunny days. I would have thought it would drop by now. ??

Everything else looks "good" according to the ideal range listings on the test kit.

I'm just surprised is all, as last year "the pool store", over about 3 weeks and $250 worth of chemicals got me to where I am now after just over a week and less than $20 worth of chemicals!

Thanks
Paul


My opinion: all good. Expect the 7.2 pH to rise a bit with an alkalinity of 120 but that's okay, and don't worry about the calcium it's fine.

Depending on where on the planet you are located, it may take a bit of time for the 10 ppm chlorine to deplete from the sun's uv. The CYA test is notoriously difficult to interpret unless the turbidity is read by a photometer; again that figure is perfect.

The chlorine level you are persistently reading at 10 ppm may be the maximum level that your test kit can measure, anything beyond 10 ppm may just read as 10 ppm.

Pool maintenance is only expensive if you go to pool stores.

What type of chlorine will you be using this season?
mound
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Pool Newbie
Posts: 3
Joined: Wed 09 May, 2007 11:46

Postby mound » Wed 09 May, 2007 13:25

Thanks for the response!

I am in upstate NY.. The past 4 days have been sun filled, and the pool is in a south facing lawn with no trees so it gets full exposure all day long. Although - I have kept the solar cover on all day and night, perhaps that is preventing the UV exposure. I'm trying to get the heat up (no heater) but do you perhaps think I should remove the solar cover during the day when it's sunny?

I have yet to swim in the pool and it is crystal clear so there isn't much for the chlorine to gobble up. Should I just start swimming now? is 10ppm unsafe?

I am using a drop-based test kit, and was diluting the pool water 4:1 with distilled water and then multiplying the chlorine readings by 5 because the test kit doesn't go that high. This yields the reading of 10. All other tests were done with an undiluted sample from the pool.

I have several gallons left of the regular old bleach (6% sodium hypochlorite solution) that I used for the opening shock which I might as well continue using. I do have about half a bucket of trichlor tablets left from last summer which I might as well use up.. I know they add CYA to the water, but my level being as low as it is, I see no harm in doing so. I guess I'll need to train myself to test chlorine levels every day if I go with the liquid.
me_too

Postby me_too » Fri 11 May, 2007 14:02

I don't know about the solar cover. The 10 ppm being swim to safe is up for debate a bit as the effectiveness of this 10 ppm ultimately depends on the CYA levels, here 30 to 40. My answer to this: I don't know. Sorry.

If there's already CYA in the water there may not be a need to add bleach everyday. By testing the chlorine every day you can probably determine how long before you need to add some, and then only add what you need.
Demons1964
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Posts: 39
Joined: Tue 01 Aug, 2006 19:32
Location: Australia

Postby Demons1964 » Fri 11 May, 2007 19:08

I have a solar cover with SWG, it requires about half the chlorine output compared to pre-cover.

I'm not sure either on 10ppm being ok to swim in. I suggest you play it safe, pull the cover off during the day for a couple of days and let the sun bring the level right down. All other chemical levels are great except pH is a smidge too low, 7.4 is ideal but 7.2 is fine to swim in.
mound
Pool Newbie
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Posts: 3
Joined: Wed 09 May, 2007 11:46

Postby mound » Mon 14 May, 2007 10:48

ok thanks.. chlorine is down to 3ppm which is a good maintenance level I believe.. really what's the difference between 7.2 and 7.4 for ph? in terms of effect on everything?

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