Welcome to TPT!
I live in the Seattle area, Seattle Public Utilities supplies water many of the surrounding areas, and the water is very, very soft. Unless something looks 'out of whack' I typically check the following monthly: PH, nitrates (NO3), hardness (dKH & dGH). When cycling a new tank I also check Ammonia and Nitrites. If things do seem unusual I check phosphates (P) and Iron (Fe). I use API test kits for most of my tests.
Here is Washington State we have one of the most active aquarium clubs in the country
, with plenty of 'plantheads' among our members. The club is open to Washington State residents and has monthly meetings at Seattle Pacific University, brings in both National and International speakers, and if the speaker allows it records their presentations (now in HD) and makes them available to our members either on DVD or streaming
. In the past we have had Tom Barr (twice), Karen Randall (from AGA) twice, Bart Laurens (Holland - Dutch Aquascaping) Christel Kasselmann (Germany - Plant Exploration), along with Ad Koenings, Gary Lange, Dick Au, and a host of others. If you are in the area check out a meeting as a guest, you won't be disappointed. October 10th is our next meeting, it will be on 'Blackwater Aquariums'.
We have some great local aquarium shops in the area such as Aquarium Co-op, Aquarium Zen (ADA Dealer), The Fish Store, Denny's Pet World, Aquaria LLC, that carry excellent selections of plants, both common and 'rare' varieties that they typically purchase from GSAS members. WA Fishbox
is a local online forum where many hobbyists hang out. I hope you can make it to a meeting sometime!