How to convert water GH/KH?

Hey again guys,

I just bought a water hardness test kit yesterday to measure my water hardness and compare it to my PH, to see how much C02 is present in my tank. Well i got a reading of 100 mg/l for KH. My Ph has been steady for weeks at around 7.2. Now this site i have below, shows the KH readings on the left of the chart from only 0.5-15?

http://www.algone.com/planted_aquarium_pf.htm

How do i convert my KH reading of 100, so i can see what my KH is from 0.5-15? Im a bit confused here as im new to these hardness test kits.

Also while im at it, i got a reading of 160 for my general harndess, again how do i convert to get a reading from 0-40? For the fish i have they say your water hardness should be around 10 dGH. Im sure my hardness isnt off the charts, but rather its just a simple conversion im not aware of.

Thanks.

RTR said:

Divide the ppm (mg/l) by 17.86 to get degrees.

100/17.86 = ~5.6 for KH

160/17.86 = ~9 for GH

Click to expand...

Thank you very much!, so basically that mean my C02 reading is at 10 according to that chart. Is this good or should I increase it? Currently i have about 1.5 watts per gallon of lighting. Soon though i will be increasing my lighting to 3 watts per gallon. From what i understand, higher light means you need more C02 concentration. So for example when i do convert to 3 watts per gallon, i will have to get the C02 in the 15-20 range? Also would there not be a ph spike if trying to accomplish this?

Am i on the right track here?