SG of calgary tapwater

[midgetwaiter]

1. First calibrate the refractometer in pure fresh water. That can be distilled water, RO water, RO/DI water, bottled water, and even tap water with reasonably low TDS. Calibrating with tap water that has a TDS value of 350 ppm only introduces about a 1% error in salinity, causing readings in seawater to read a bit low. So 35 ppt seawater (specific gravity = 1.0264) will read to be about 34.7 ppt, and have a specific gravity of about 1.0261.

I figured it would be much of a problem but that's a lot less than I thought. Considering that the city's water reports put the TDS < 300ppm even for Glenmore you're at the point that you'd never know the difference, you can't measure that accurately with our gear.

[kwirky]

I'm from calgary, and when I mix batches of water from RO/DI and tapwater, the SG's exactly the same, but the alkalinity's/pH is different. I have a calibrated refractometer, too (RO/DI calibration).

do you mean alkalinity?

[bubblepuffer]

I always calibrate my using distilled water which it should read 1.000. Well I am from Edmonton, and I think the tap water in the city is around 1.002 or something like that. Checked few times about a year ago.