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Re:Growing conditions for plants and algae

Karen and Shaji,

The algae problem continues. It's not really severe, but enough to keep me
alert. To objectify: I have to remove the green algae coat from the front
and side glass screens every other day to maintain a pleasant 'look'.
Green 'coating' algae on the plant leaves and driftwood seem to be 
controlled by the five SAEs fairly well, but there are some 'hairy' algae 
on some of the plants, especially on the fine-leaved Rotala wallichi 
(sp?). Sorry I can't idenitfy the algae correctly. The hairy algae make 
long threads which float in the current like flags in the wind. The SAEs 
don't seem to like them too much. Despite these algae, the wallichi are 
still growing well. 

I think Karen's point about the inital instability of a new tank is well 
taken, that's why I hesitate to add more SAEs. Should I have more than
five in this 5'x2'x2', densly planted tank? They are still only 5 to 6 cm 
long.

I did increase the iron levels to 0.1-0.2 mg/l, mainly by adding some of 
the Tetra tablets to the substrate near the large Echinodorus.

So what I'll do next is try to lower the pH a little. The reason why I 
initially aimed for 7.3 and only about 15 mg/l of CO/2 was some concern
about how long the 1500g CO2 bottle would last. In this big tank (open) 
it's really bubbling away! The rate in the bubble counter is just about 
too fast to count and the valve is open at least three fourths of the time.

Interesting side note: in support of the experimental finding of George
Booth, I can report that there seems to be very little, if any CO2 loss
caused by the trickle filter. I measured pH in the water before the TF and
after and there was no detectable difference in pH. The measurements were
repeated about five times with a pH electrode (Dupla). If the TF had
stipped some CO2 out of the water, some pH difference should have been
detectable. 

My surface current is gentle, but visible, so most of the CO2 will be lost
there or be used by the plants. 

I have looked through some of the catalogues of our lab suppliers today 
trying to find some EDTA and Fe(II) compounds <VBG>. Anyone have any 
experience in mixing their own? I have some professional chemists at hand 
here, so maybe we can start some competition for Dupla.

Michael