I use to use weekly bacteria, BZT. Now I just use it if something is "off".
Last year's "off" was water not being as polished as I'd like. I think I
used it twice. Ever since I've kept the filter running on slow mo thru
winter I haven't had to jump start it.

Salt. I usually keep it up around what Ingrid mentioned 0.05-0.1%,
sometimes a tad higher in spring. I also do a Prazi treatment spring & fall
for flukes.

For the lily pond I don't use any salt, and rarely BZT, and then I'm using
it more for the enzyme action to help break down mulm.

That's my MO. :-) ~ jan

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(Do you know where your water quality is?)