Re: Aquatic Plants Digest V1 #12

I've been lurking here for awhile and I have some plant questions. I've had
a 48 gallon tank set up for more than a month. I have a Biolife filter that
so far I can only say nice things about. It's efficient enough that the
tank never had to go through a "cycle", at least it hasn't yet. I have 21
fish in the tank (all small). I know that's a lot to begin with but I went
from two 20 gallons to the 48 so I already had the fish. I have set this
tank up to be good for plants ( I hope). I have "Laterite" in the gravel.
At the moment I have a hood with two ultralume bulbs but soon (this
weekend, baring disaster) I will have a hood with four ultralume bulbs. I
have planted many kinds of plants. So far they are all hanging in there. I
am injecting CO2 with a DIY yeast bottle. At least I think I am. So far the
plants have never given off any oxygen bubbles. Does this mean that the CO2
is not getting into the water? I have had trouble because there is no way
(I've found yet) to get the CO2 tube into the Biolife filter power head. I
have found a way to break up the big bubble. I put a short piece of clear
tubing over the filter output and stuck the CO2 tube into the side of this
tube so that the bubble forms right in front of the outflow. The water
snatches the bubble and breaks it up and ejects the small bubbles. Is this
enough? Would it be better to trap the CO2 and let it dissolve slowly? I do
have a powerhead I could use but that means changing the currents in the
tank. At the moment the water circulates from one end to the other
perfectly.(One can see that by the salvinia that floats on the top.) Will
interfering with the currents mean possible "dead" spots in the tank? Or is
this nothing to worry about?

Do I need to add liquid fertilizer even with the laterite in the gravel?
And should I remove the charcoal insert from my filter? An aquarium store
guy told me it wouldn't matter after a week or two as the charcoal would
cease to be effective. True or false?

And, last but not least: HOW does one disolve magnesium in aquarium
water??? I have some magnesium tablets but trying to mix them with water is
hopeless. Is there something liquid I can use to get some magnesium into
the tank?