Daniel Morrow wrote:

snip

co2 injection is just plain too expensive. I have heard that liquid co2
(like seachem excel co2) works great, at least by some brands. I do wonder
if massive aeration causes co2 to come back into the tank in a small but
significant amount so a small amount is always still there.

Aeration ("massive aeration" is not necessary) or surface turbulence
keeps the tank at atmospheric CO2. So yes, in a non-CO2 injected tank,
the CO2 the plants use up is replaced. For this reason, it's usually
halpful to have some surface turbulence or an airstone in a planted tank
that doesn't have CO2 added.

My plants do really well with Seachem Flourish Excel. It's much less
hassle than DIY C02.

--
Elaine T __
http://eethomp.com/fish.html '__
rec.aquaria.* FAQ http://faq.thekrib.com