I am thinking of using Flourish Excel as a carbon source for my planted
tank
and have a few questions:

I use Excel on my 10 gallon, low (1.5 watt/gallon) light, low tech plant
tank, and I have been happy with it for this one, which is in a location
that does not lend itself well to CO2 injection. On my 55 gallon, with 2
watts/gallon lighting, I do use a CO2 canister.

1) Will it cause PH fluctuations (like CO2 injection) ?

I 've not noticed any fluctuation in the pH- it stays quite steady for me.

2) Other than PH, will it alter my water chemistry ?

Not that I've seen in my tank.

3) Are there any issues with it that I should be aware of ?

Be careful of overdosing- there have been some people who have reported that
some plants (mainly crypts) will melt if they overdose Excel too much. I've
never had the problem myself, but I'v never tried to go way over the
recommended dosage, either. I also do not add it all at once- I add a bit
every day with a measured eyedropper.

4) Based on anyone who has tried it, how effective is it ?

I would say that for a relatively low light, low tech set up, it works just
fine. My 10 gallon has been doing quite well on Excel as the only carbon
source for over a year now.

-Mak
http://www.thirtytwopaws.com/mak
Updates 1/30/03

You can't ask to start over just because you're losing the game.