T8 & T12 + decalcification?

I have been following the thread on T8 and T12 bulbs, and have a question.
My favorite bulbs, the PennPlax Ultra Tri Lux 40W bulbs, are 1.25" in
diameter.  This is right between a T8 and a T12.  What is it then?  A while
ago, I went shopping for electronic ballasts, and talked to a few people at
industrial lighting places.  They said that I have to match the ballast to
the bulb.  That is, buy a T12 ballast for a T12 bulb, etc.  I don't know
what the Ultra Tri Lux is, but I settled for a T12 ballast.  Is this okay?
Does anyone know?
It's working okay, but I just wonder about any life-shortening effect.

On another matter, I decided I've had enough with weekly pruning of my
plants (enough credit at the fish store to last a while), so I disconnected
my CO2 injection last week, hoping to slow down the growth.  The plants are
still okay, but I have noticed that the Anacharis have formed a sandy layer
on the leaves.  Is this the decalcification effect?  And will it be bad? I
have been monitoring the pH, and it's about stable at 7.6 (tap water here is
8.1 pH, 18dGH, 8.4 dKH).  pH was around 7.2 with CO2 injection.  What else
should I do to balance things out if I don't want the plants to grow so
fast?  Reduce lighting duration?  Right now it's about 10 hours of 120W (80
bright Watts of Ultra TriLux, plus 40 dimmer Watts of Vita-Lite, on 75
gallon aquarium) plus 3/4 hour of sunrise/sunset periods on each end (40W).

BTW, what is the scientific name for Anacharis sold in the Western United
States?  I can't decide if it's Egeria densa or Elodea canadensis.

Thanks for any suggestions,

in San Diego, CA