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hoppycalif · 03-10-2006, 08:57 AM

Last night I went to my local grocery store and bought a gallon of water sold for steam irons, etc., labeled as RO water. I poured out about 80% of it into a large shallow bowl, added about 1/32 tsp baking soda, and waited for things to stabilize. I measured KH=2, PH = 7.2 to 7.6, getting different results (or different interpretations of the color) for three measurements taken from 2 to 12 hours later. The KH test I did with double the amount of water, so it is pretty accurate, but the PH is very iffy. Today I have mixed a small batch at about KH=1, and added another 1/32 tsp to the bowl to get KH = about 4. I will check PH/KH in about 4 hours. I'm already almost sure the actual equilibrium CO2 is more than .5 ppm and closer to 3 or 4 ppm. Remember, we don't care what the theoretical value is, just what the water reaches after sitting open to the air for 12 hours.

03-10-2006, 08:57 AM	#33 (permalink)
hoppycalif Senior Member Join Date: Apr 2005 Location: Sacramento, CA, USA Posts: 5,208 iTrader Ratings: 20 iTrader Positive Rating: 100% Plant Points: 227345	Last night I went to my local grocery store and bought a gallon of water sold for steam irons, etc., labeled as RO water. I poured out about 80% of it into a large shallow bowl, added about 1/32 tsp baking soda, and waited for things to stabilize. I measured KH=2, PH = 7.2 to 7.6, getting different results (or different interpretations of the color) for three measurements taken from 2 to 12 hours later. The KH test I did with double the amount of water, so it is pretty accurate, but the PH is very iffy. Today I have mixed a small batch at about KH=1, and added another 1/32 tsp to the bowl to get KH = about 4. I will check PH/KH in about 4 hours. I'm already almost sure the actual equilibrium CO2 is more than .5 ppm and closer to 3 or 4 ppm. Remember, we don't care what the theoretical value is, just what the water reaches after sitting open to the air for 12 hours.