I just setup my first planted tank using a lot of information gleaned
from this newsgroup.

Setup:

Tank Size: 55 Gallons
Lighting: 2-55W CF lights from AH Supply
Substrate: 6 bags of Onyx Sand
Filter: Magnum 350 - using micron filter
Plants: TrueAquarium 55 Gal assortment - mostly one with low to
moderate lighting requirements
CO2: Carbo-Plus

Tap Water Quality: pH 7.6
kH 3
GH 3

Here's my problem ...

I setup everything in anticipation of the plants two days ahead, filled
the tank 3/4 full and to let the Onyx dust settle. I also dropped in a
handful of 'seeded' bioballs from my LFS to get a headstart on the
bacteria. Checked the water after the second day and saw that the kH
had crept up to 4 and the GH up to 4.5 - I assumed it was from the Onyx
- but I did not start the Carbo-Plus.

Added the plants last Thursday - nice selection and they arrived on time
in very good shape, topped off the tank, set the lights and Carbo-Plus
on timer to go on for 11 hours per day. I set the Carbo-Plus at 3 LED
bars.

Checked the water on Friday, expecting the pH to have gone down, but it
was still at 7.6 - upped the Carbo-Plus to 4 LED bars.

Checked the water on Saturday, still waiting for the pH to go down, but
it was still at 7.6. Also, checked Ammonia (just a trace) and Nitrite
(none).

Checked again last night - Still a pH of 7.6. Also, checked Ammonia
(none) and Nitrite (none). Picked up a Nitrate kit and tested at 5ppm.

Any clues to why there is no pH drop, hence no CO2 being added to the
water? I've checked the Carbo-Plus setup and it it installed
vertically, opposite end of the tank from the intake to the Magnum,
directed the return a little bit downwards to try to minimize surface
turbulence.

Any thoughts, suggestions or opinions welcomed.

Tim Louie