Re: CO2 Measurement etc

Joanne wrote:

>I would tend to look somewhere else in your system for problems rather
>than a CO2 deficiency.  Firstly, do you measure your iron content to see
>if you are adding enough dupla fertilizer.

Yes, I measure Fe using the recently disparaged Dupla kit.  I agree with 
George, it is hard to read.  Perhaps I need a better kit.

>Secondly, are you using the whole Dupla system, particularly Duplagan.  
>Lots of people don't seem to use Duplagan but the other Dupla fertilizers 
>don't contain Mg.

I started using Duplagan about 2 months ago when this issue of Mg was 
first discussed.  I haven't really seen any benefit.  I have been using 
the drops and the tablets from the outset.  It might be cheaper if I just 
bought the company.

>Thridly, do you use laterite?

>Fourthly, how often do you do water changes?

I aim to change about 15% a week.  I add the Dupla tablets at this time.
>And, how much light do you have? (watts/gal & dimensions of the tank please).

The tank is nominally 75 G (48" L x 18" W x 20" H).  There is 180 W of 
fluorescent light, giving about 2.4 W/G.  The bulbs are a mix of 
UltraTrilux and Tritons.  The guy at one of our local stores, where they 
have some beautiful planted display tanks, blanched when I told him 
this. He said this was way too much light and I should only need 80 W.  

All in all, I think I have things quite well set up.  This is the reason 
that I leapt at the possibility that the tank was CO2 deficient.  Since I 
increased the rate of CO2 addition there has been a noticeable 
improvement, but I will be happy if anyone has any other suggestions to make.