"Dave M. Picklyk" empowered us with this mighty blow
against the Patriarchy:

I started my C02 DIY last night, now I'm getting from 35-40 bubbles a
minute. The water has about 19ppm C02 right now. How often do I test
for C02 levels? Every day? Every few days? The KH tester kit requires
me to use about 11 drops per test!---I don't want to buy 15 test kits

Personally I don't bother testing KH, I just test pH to make sure it stays
within the right range (more important to the health of the fish). Your KH
shouldn't increase over time, so as long as your pH is at the right level,
you know you're not injecting too much CO2 (bad for the fish). When my pH
starts increasing, I know that it's time to change my CO2 mix (usually
after about two weeks). Your plants won't suffer from a temporary drop in
CO2.

I'm noticing "pearling" (that the right word?) of the oxygen under the
leaves... so I'm really happy.

Cool! Isn't it great when that happens? :-)