I have a moderately planted tank 20 gallon tank with 3 watts per gallon. I
have been injecting CO2 with the Hagen Natural Plant system for about 1
week. I increased the light from 30 to 60 watts when the CO2 was added.

I finally bought a descent test kit (Aquarium Pharmaceuticals Freshwater
Master Test Kit) and tested the water after the lights had been on for about
11 hours with the following results.

PH 8.2
GH 26
KH 11
Ammonia 0
Nitrite 0

This works out to a CO2 of 2.1ppm using the calculator at
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

This seems low for even a non-injected tank. The CO2 bubbles at a rate of 6
bubbles per minute. They get very small by the top of the diffuser, so they
must be dissolving. Surface agitation is from a hang on back filter as low
as it can go and an air powered UGF as low as I can set it on one tube and
none on the other.

What can I do to raise the CO2? Or should I give it a month and see haw the
plants react?