Originally Posted by aklick
Thanks. I called and they said both numbers are typically between 7 and 14 MC (?) per liter. He said we have "very soft" water. He says they test it once a month
Does that help? I also found this: but it's a bit confusing :) http://www.somersworth.com/vertical/...ity_Report.pdf
The chart in the link is mainly concerned with contaminant, understandably for drinking water. They mention at the end of the second page about monitoring pH, conductivity (this relates to GH) and such, but from what they told you already I don't think you need to pursue this.
So, soft water means low KH/Alkalinity. And that is not a problem, but it does explain why the pH lowers in the aquarium. So due to the natural organic processes the pH will tend to lower as the water becomes more acidic. Regular partial water changes of half the tank every week will work to keep this stable.
You didn't mention the fish, but with soft water and an acidic pH, do not have livebearers or any fish that need hard water. Soft water fish will be fine, and there are many to choose with this sort of ideal water. We have fish profiles, second tab from the left in the blue bar, and water params are given for each species.
So going back to the initial post issues: nitrates occur from the organics decomposition in the substrate. Here again, regular weekly water changes work to keep these in check, and you can vacuum the substrate during the WC . With live plants, I tend to leave the substrate alone as this is a major source of nutrients, especially CO2 for the plants.
I would not use baking soda. It is short-term in effect, and increased organics will off-set it. Plus it is detrimental to fish long-term.
Let me know if anything further needs to be covered.