[QUOTE='vspec';431575;43157577]Wow your thread moves quickly.
Nice purchases too bud. Its great when we get some new toys to play with!
Yup - Water is some funky stuff, the more you take the time to understand it, the more you appreciate everything else that interacts with it. Sooner or later if you follow that path, it prompts you to question alot more of what you see & hear around you. Trust me, if 50% of the population took an interest in chemistry, we'd bring corporations crumbing to the ground with the sh^t they feed to us. But thats left for a "I'm hammered"

conversation.
Water (to me) is like a silently hostile market place, it forces elements entering to trade and swap, then once the exchanges occur, the entrance fee it striped determines the environment. aka PH & further more, stability down the line.
If your breaking it down & in relation to the topic,
Water =
2Hydrogen &
1Oxygen.
Carbon Dioxide =
1Carbon &
2Oxygen.
Its worth pointing our that when CO2 & H20 molecules interact (the market place), they combine to produce carbonic acid.
Carbonic acid =
2Hydrogen,
1Carbon &
3Oxygen.
The transfer strips the hydrogen which reacts with opposing hydroxide in solution (negative / positive) which effectively cancel each other out.
Result = Carbonate. As above,
1Carbon &
3Oxygen. I'll stop here on the this one, as its starting to move away from the aspect im trying to explain.
If we revisit the Hydrogen & Hydroxide Ion interaction you will notice thats the entrance fee taken by solution from the elements.
Or another way to look at is its just like two opponents doing battle with a bag of opposite polarity magnetic marbles. Once they enter the arena, the balls smash with their counterparts, the one that has a greatest numbers of marbles logically wins & dictates the PH environment.
Now you can look at it from ether perspective, hydrogen (H+) takes hydroxide (OH-), or hydroxide takes hydrogen, however by definition, the word pH is stands for pondus Hydrogenium. Which literally means the weight of hydrogen.
When the number of hydroxide ions is higher, the solution is considered basic. When the number of hydrogen ions is higher, the solution is considered acid. When you have equal numbers of both, the solution is neutral.
The solution in the glass vial is just like any other testing reagent, it reacts to the above & displays accordingly.
My question is how often do they recommend replacing it?[/QUOTE]
that was a nice read, thanks! folks recommend swapping out the 4dkh solution every 2-3 weeks