Re: Water changes start growth
I experienced the same situation a while back--within an hour or so
after my 15% weekly water change, my plants would start to bubble.
This lasted for about 3 days, then there wouldn't be any bubbles until
the next water change. I fertilized regularly with Flora-Boost. I
eventually attributed it to CO2. My tank would have a CO2
concentration of 0-1 ppm before the water change, but afterwards the
CO2 would be about 4-5 (according to LaMotte). This prompted me to
add CO2 via yeast-sugar, then I graduated to a 20# cylinder. Now, my
plants bubble all week (with the lights on, of course). They no
longer "respond" to water changes like they used to.
However, you stated that you already add CO2. Perhaps it isn't
completely dissolved or is being diffused out too rapidly. I am not
convinced that it is any other macro- or micro-nutrient that is
causing this, as photosynthesis requires light, CO2, and water to
occur (Growth requires N, P, K and micronutrients).