Ho Do I Get Co2 Level Of 30 Ppm ?

[s007]

Using presurized co2 system and 2 drop checkers on both end of my tank how do i get CO2 level of 30ppm ?

I have no idea regarding bubble counter which i have taken off from my co2 as now i use ladder difusser and anyway the bubble counter had bubbles the size of approx 1/4 normal air tube bubbles and now i count airtube bubbles as 1 bubble.. At the moment i have 2 bubles every second. PLease advice .
THanks

 

[aaronnorth]

how do i get CO2 level of 30ppm ?

using the DC as a guide, slowly raise the levels of CO2 being injected into the tank, with the needle valve.