Re: Bubbles During Water Changes

     My plants pearled for 2-3 days after a water change, and I suspected 
     they were CO2-limited (this is back when I did not fertilize with 
     CO2).  I bought a LaMotte CO2 test kit, and measured CO2 after a water 
     change (3-4 ppm) and when the plants stopped bubbling in 2-3 days (0 
     ppm).  This prompted me to add CO2 via the sugar-yeast method, and my 
     plants bubbled all week long.  CO2 was now 10-15 ppm.  I later 
     graduated to a 20# cylinder, and finally to PMDD.
     Others have experienced pearling after a water change, and they 
     already add CO2; obviously, CO2 is not always the culprit, but it was 
     in my case.