Great looking tanks!
Are the riccia giving your problems yet? I started off using those as carpet too, easy to grow, lush green... then the growth just became unbearable, random floaters growing out and floating to the surface, getting stuck on other plants, every day. Eventually tore it all out and replaced them with HC, HM, Marsilea Minuta, Glosso, etc.
What part of Miami are you in? My tap is 160 tds 7 ph here in Brickell, 0.25ppm Ammonia but that gets used up quickly by plants, haven't had to treat it other than Prime for chloramines. I don't think your pH is that high 8+, let it sit for a few hours before testing since oxygen diffusion from the faucet raises pH.
I'm trying to avoid RO/DI as long as possible since I'll probably mess up remineralizing.