New Water/Refill

[duraleigh]

...is it normal for PH to take a while to drop after a new refill

Probably not. How high was "sky high"? Perhaps you have not yet dropped it within the range of your test.

[doggie]

How high is your free chlorine? Sometimes a really high chlorine level will make the ph test result abnormally high.

[Simmons99]

You didn't mention if this was a concrete pool - is it a new finish - did you just have the finish acid washed? That may make your PH rise considerabely everyday until the finish has cured.

How long are you waiting from the time you add the acid until you are testing the PH again - is it the next day, 10 minutes, an hour? I add acid with the pump on and then brush the whole pool - it takes about 20 minutes and helps to stir things up - then I retest.

Also how large is your pool - I find with ALK of 80 in my pool - it takes about 2 cups to go from 7.8 to 7.4. The larger the change in PH - the more it will take - and the larger the pool the more it will take.

I would refrain from adding a whole gallon at once - I wait a day between additions just to verify a reading wasn't bad due to the pool not being mixed up yet.

[h20man]

yes it was acid washed...

PH - 7.5
ALK - 80 (just dumped more soda)
CL - 2PPM
CALC - 50
CYA - 20

concrete pool 20k gallons, pebble sheen surface


looking to get the CL up tonight & then start on the CYA & CALC

thanks!

[Simmons99]

You could have a rising PH due to plaster dust in the pool. Your numbers look fine - you could add a little more CYA to hit about 30ppm - but your chlorine should only need to be around 3-4ppm at a CYA of 30.

ALK at 80 is fine also - if you get this higher it will tend to raise your PH - so if it is stable at 80 - just leave it alone. My pool has ALK at 75-85 depending on whether PH is 7.2 or 7.5.

Just test the PH once a day and add SMALL amounts of acid to drop it a couple of points at a time. I add about 2 cups to the pool about every 3-4 days now - at first it was daily.

[h20man]

cool, my next question is the Hardness ....that calc chloride stuff is $$$$$ is there an alternate store bought product? I'm @ 40ppm ....need to get up in the 200 range I suppose...

[chem geek]

cool, my next question is the Hardness ....that calc chloride stuff is $$$$$ is there an alternate store bought product? I'm @ 40ppm ....need to get up in the 200 range I suppose...

You could use Calcium Hypochlorite, also called Cal-Hypo, which will increase both your chlorine (FC) and your calcium (CH) levels. Try and get the 65% purity form of Cal-Hypo unless it's much more economical to get a less pure form. One pound of the 65% stuff in 10,000 gallons will raise the FC by 7.7 and the CH by 5.5 so if you switch to using this instead of liquid chlorine or bleach as your chlorine source, then you can slowly get your CH level to increase.

Also, your combination of pH, Alk, and low CH have your pool water in a corrosive state and though normally we don't talk about that because the number has to be pretty extreme to cause a problem, your numbers lead to an index of -0.76 which is where I might start to worry (we don't have good data from forum users when corrosion occurs, but on the other side with scaling and cloudiness some report this at an index of +0.75 while others report it only when they get to +1.0). Though it is true that the curing of concrete will lead to an increase in pH and alkalinity, it is also true that corrosion (dissolving) of your concrete will also have these same effects. If I were you, until you get your CH level up I would keep your pH much higher, perhaps at 7.8 or so. As you add more Calcium you can then lower your pH level. Perhaps I'm being over-conservative in this but adjusting the pH is a pretty easy thing to do compared to the other items.

One final note: though the Calcium Chloride is not inexpensive, it's only something you will do (in large quantity) once. It's not an ongoing maintenance item unless you have large amounts of backwash or splash-out.

Richard

[Simmons99]

cool, my next question is the Hardness ....that calc chloride stuff is $$$$$ is there an alternate store bought product? I'm @ 40ppm ....need to get up in the 200 range I suppose...

Is the comoany that did the acid wash give you warranty guidelines? My Calcium level rose from ~60 to 275ppm on its own in a week.