Phosphates or Silicates slipping past TDS meter?

[asylumdown]

Yah compared to Vancouver Metro, Abbotsford has some issues. I think you *can* have really good water, but it all depends on what mix and from what sources you're getting out of your tap at that particular moment. Obviously it's always safe for human consumption, but 'human safe' and 'reef safe' have different thresholds.

The 'legal limit' for nitrate contamination is 10ppm, but that's Nitrate reported as Nitrogen (a weird yet standard practice in water treatment and some areas of chemistry), which is actually closer to 44ppm nitrate reported as nitrate, which is how we talk about it in the hobby. The good news is that the average nitrate levels from the other two sources are both below 1ppm, and Abbotsford publishes a report indicating that they only get 5% of their water from the aquifer wells per year (none of which have nitrate levels acceptable for a tank), but that's an average for the whole system over a year. Moment to moment you never know what the mix is coming out of your taps.

Interestingly, the other element that routinely tests above the 'legal' limit coming out of the aquifer wells is manganese, which just so happens to be critical to oxygen evolution during photosynthesis. I haven't been able to find anything that showed elevated manganese encourages the growth of cyanobacteria (though I haven't looked all that hard), but people have been testing cyanobacterial mats as a zinc and manganese remediation technology because they're really good at sucking it up. Food for thought anyway.

Anyway I think you're on the right track, good luck!