In article ,
says...
PH is between 5.0 and 6.0 (bit closer to 6), ammonia is 0 and nitrite
is 0.1.

That's a low pH. Unless you are breeding sof****er fish like neons,
you'd have greater margin of safety if you put a couple of limestones
in the tank (which'll buffer the water and give a pH of 7.5).

So it's okay to put some limestone in? I read some websites that said
that rocks were okay to add as long as they *weren't* limestone, so
we collected some rocks and tested them. We set aside those that
contained limestone, but there are a couple of great ones (the kids
particularly like the one that looks like a fossil of an alien's head
G), so if we *can* use them...

I also read somewhere (thought it was here, but can't find it here
now) that placing some seashells in the tank will increase the ph. I
can find a few websites that offer that advice - eg
http://www.fishtanksandponds.net/set...tank_decor.htm -
but other websites that say "under no circumstances". Opinions
please...

(Hoping that it's okay, because after I read it and before I read not
to do it, we went off seashell-collecting today LOL. If it *is* okay,
how many seashells are we talking? Most of those we've got are an
inch across or less. We also got some that look like snail-shells -
empty ones! - is it the same for them?)

This is a really good interest for someone who loves to learn LOL

--
FishNoob