Question about CH Test Coloration

[jmarcum]

Ah okay. Gotcha. I think I may go to the dreaded pool store tomorrow just to compare their readings of the water to mine. I'm curious to see how closely I am interpreting things. :-) How about that other thing I asked above....My PH was low so according to the pool calculator, which BTW I like so much that I bought the app today, so I added the suggestion amount of Borax. How long should I wait to retest ph? I ask because I went ahead and retested after about 2 hours and now the Ph is off the chart high. I'm hoping that is because I am just too impatient.

[CarlD]

what is your pH? Anything between 7.2-7.8 is do-able and not too bad

[jmarcum]

As far as the pH goes my test before adding the borax was 7.0. The calculator said to add 67 ounces so I did. Two hours later the reading was so dark that I'd say it's over 8.0.

On the calcium test it took me a little while to figure out what you meant when you said "old reagents" I bought this kit during the winter but I did leave it ouside all winter. I didn't know I wasn't supposed to do that until recently. This is the color "red" that I get...

[jmarcum]

I know the lighting is terrible in my house but this is the color after 40 drops...

[CarlD]

pH: With almost all chemicals we always say NEVER ADD THE FULL AMOUNT! Add 1/2 of the "recommended" amount, wait a couple of hours and test again. Gradual adjustment is the key. i don't use the pool calculator for just that reason--too easy to overshoot your goal. It works best for bleach, IMHO.

Now you need to add acid to your pool to bring pH down. I don't know how big your pool is so I would start with a cup of Muriatic acid. You can use Dry Acid instead. Either way, add it to a five gallon bucket of water FIRST before adding it to your pool. Do no breath the acid fumes...you will see vapor rise from the jug. Keep it away from your face and skin and wear safety goggles and gloves. Always add the acid to water, not the other way around!

Then pour the bucket into the pool's return stream and keep your pump on. Test pH in an hour and if it is still high repeat. 7.6 is ideal but any result from 7.3 to 7.7 I would leave alone.

CH: the colors look fine to me. 40 drops means a CH of 400ppm and you do not want to exceed that in any pool or you may face clouding or scaling. See if your pool store tester confirms that number.
However, I would go on line and order replacement reagents (testing chems) just to be sure. Always store them in a cool, dry place, indoors.

So, what is the ONE additive I don't mind overshooting on? Chlorine, of course!

[jmarcum]

Thanks again. I'll give the acid a try. From testing this am it took 4 drops to get the color down to the recommended ph. According to the ph chart that means I need a little over a quart so I'll just do a little at a time and retest. As far as the pool size goes the pool builder told me 12,000 gallons but the next time I refill it I'm going to get the water company to do before and after readings to confirm. Are any of the digital water testing devices available to consumers worth buying?

[CarlD]

I never bother with the acid demand test. My pH is too high? I add a cup of acid and recheck in an hour.

Pool volume is simple solid geometry. Once you have the cubic footage volume of the water, not the pool, you multiply by 7.48 to get gallons.