pbohart

Hi -

I just received one of the ADA knock off CO2 drop checkers off eBay from Hong Kong.

Here is my question - the instructions are in Chinese and included in the kit is the glass unit, a bottle of liquid titled Co2 indicator, and a PH color chart (yellow = ph 6, Green = ph 8, etc.).

So....I have read several posts on this from Hoppy, but I am still not sure what to do to measure my CO2.

Is the goal here to use the unit to measure PH, then measure KH using a different test kit, then use Chuck's calculator to measure Co2?? If so, I already have a Milwaukie PH unit to control my CO2 and could have done this before spending $15.

Also - do these test kits run into the same snag as the standard method of measuring CO2 via PH and KH - where if you add MG, CA, or Baking soda to your water you throw off the CO2 measurement?

Thanks for the help...speak slowly and in simple terms when replying...I am a slow learner

yoink

The idea is to have the solution in the drop checker to turn green when the desired co2 level is reached. If you used distilled water and baking soda to make your solution with a kh of 4(or the liquid that came with it if it is kh 4), the water will be green at 30ppm co2.

jeff5614

The idea is to adjust the water in the drop checker to a KH of 4 so when your pH hits 6.6 the drop checker becomes geen indicating 30 ppm CO2 ( ph of 6.6 with KH of 4 equals 30 ppm CO2 ). I believe Hoppy chose that particular KH because a pH of 6.6 using the AP kit gives a very unmistakable green color making it very easy to determine that you're at 30 ppm of CO2. If the drop checker is a blue color you're CO2 is less than 30. If it's yellow your CO2 is above 30. Hope this helps some.

pbohart

One mixes the PH sensing solution with water of Known KH. This mixture will then measure the PH/KH balance - wich we know - indicates the Co2 in the tank.

By using a "Pure" solution of known KH one can factor out the affect of added minerals (CA, MG, etc.) and test the true value of dissolved CO2.

Fascinating...glad I asked!