How many times should you pump a "wet" tester to obtain a proper CO2 sample?

To obtain a proper CO2 sample using a "wet" tester, pumping it 18-20 times is recommended. This range ensures that the sample adequately captures the necessary amount of CO2 in the fluid being tested. The pumping action helps to mix the gas and liquid phases, allowing the tester to accurately measure CO2 concentration. By using this number of pumps, you achieve sufficient circulation and ensure that any residual gas is cleared from the system, giving a representative sample.

The other options do not provide the necessary volume or mixing. Pumping fewer times, such as five to seven or even ten to twelve, may not adequately prepare the tester to capture a reliable sample, potentially leading to inaccurate readings. The higher range of 25-30 times may also be excessive, which could lead to sample degradation or unnecessary wear on the tester. Thus, the recommended pump count of 18-20 times strikes the right balance for an accurate and reliable sample analysis.