I just read that CO2 can cause a drop in pH levels so buffers may
necessary. I already add buffers and my KH is still only 3DH. If I were
to buy a CO2 system, would I be putting my fish at risk for a pH crash?


-Christie

What sort of buffers do you add? I have had problems keeping the water
stable with liquid buffers and switched to a small amount of crushed
coral to help buffer. When I had a stable PH and KH that I liked, I
started with CO2. I also found that the crushed coral approach worked
much better for the KH than buffering solutions.

If you are using liquid buffers and want to try corals/seashells my
recommendation is to add slowly and in a manner that you can remove
some/all if you add too much. For me, it only took a few tablespoons.
(it is hard to buy a few tablespoons of crushed coral, so now I might
as well do a marine tank with the extra right?)

There are some informative articles on how much CO2 will lower the PH.
Hopefully some other people can give you better info.

If you are using liquid buffers and want to try corals/seashells my
recommendation is to add slowly and in a manner that you can remove
some/all if you add too much. For me, it only took a few tablespoons.
(it is hard to buy a few tablespoons of crushed coral, so now I might
as well do a marine tank with the extra right?)


Ditto me on the crushed coral. I started using a bag in the back of
the AC 300 filter. Now I dump a handful in the tank and it's
mixed/laying on the gravel. In my old house, my KH was only about 1-2
deg KH. Now I've brought it up to between 3.5 and 5 deg. Neat thing
about crushed coral, as I understand it, the more CO2 you add, the more
it will disolve the shells and the more buffer you have. So with
shells I think the odds are slim of a pH crash. I haven't seen
anything like one yet.

steve