would love to hear your experience with using reverse osmosis water in your dirt tank, if anyone out there is. my tap water sucks - ph is near 8.6 out of the tap and its limed at the water treatment plant. very hard water.
John, we have the same water.
Try aerating it first....not to drive CO2 out of it....but to drive CO2 into it
that will precipitate the hydrated lime.
Then my water settles down to a mid GH low KH and pH around 7.8.
Watch it though, you won't have enough buffer after that so you need to add a little Arm and Hammer back to it.
I use those Rubbermaid cattle watering troughs and hold water for a week.
I'd recommend against using pure RO water in a tank. Much like you, I'm stuck with lousy tap water with a pH of about 8.3 out of the tap and extreme hardness. I tried pure RO in my current planted nano and had wicked pH spikes until I switched to a ~10% tap water/90% RO mixture. Gotta have that buffering capacity.