HI Penny, I hear you are not much of a water tester...... it makes me kind of giggle that you finally tested it and want to add
Epsom Salts. You're statement about wanting to chase params is true haha! I can absolutely help if the hardness is low. But first I have to tell you that
test strips are notoroiusly inaccurate, so if you can at all, grab yourself a
liquid test kit like the one API makes or get your water tested at an LFS that uses a liquid test. Then adjust if needed. I just really don't trust the strip results and adjusting based on that is like adjusting blind IMO.
It's possible
nitrates are nil or close to nil with all the plants, but I'd for sure make sure that's correct, especially hardness before you play with it.