The stuff I used is called dolomite lime. It contains mostly calcium
carbonate and magnesium carbonate.

The pH has been fairly stable from day to day and is ranging from 7.5
in the AM to 8.5 at the end of the day. I am also having a big algae
bloom, and I have some elodea, so I think that is partly responsible
for the swings. I also have barley bales in there and I'm netting out
what algae I can.

My buffering capacity is still on the low side, so I got some oyster
shells for koi ponds and have them in a bag. So far, so dramatic
change.

I am trying to do whatever I do *carefully* and *slowly* and only
after a great deal of thought of the pro's and cons. Oy.

Joan

did you get a pH on the water? landscape lime could be quicklime and
drive the pH up over 8.
you need dolomitic limestone, it is almost like sand, off white with
dark gray flecks, a little course. Ingrid