The calibration fluid I'm using states it's for a refractometer at 35ppt, 53mS, with a refractive index of 1.3394 @77° (currently 75.5°). The directions on the opposite side of the bottle are for refractometers only. I waited 45 seconds after placing the solution on the prism before checking as indicated in the instructions on the bottle.
It has been about 27 hours since I mixed the water. I topped off the buckets with fresh water to bring them back to 1.026 (fresh calibration on the refractometer) and then checked them with the Coralife hydrometer (swing arm type) and got 1.027. New bottle of alkalinity reagent (HI772S) arrived today so I grabbed it and a new curvette and retested samples from a different bucket than yesterday.
Alk - 9.6 (171)
Ca - 500+ (didn't bother refilling syringe to see exactly how high it was)
Mg - 1560
Last time I sent in a Triton sample I dumped the results into a calculator which indicated a salinity of 35.26 (1.0266) where I had measured 1.025 with the refractometer at the time (pretty sure I calibrated it at the time but that was indicated in my notes) so I don't have much reason to suspect my instruments and/or calibration solution is to blame.
To compound the issue...
Samples collected 8 July
My results/Triton
Ca 420/456
Mg 1335/1356
Samples collected 11 Aug
My results/Triton
Ca 435/460
Mg 1350/1371
My results were lower than the Triton analysis on both samples. I didn't note salinity when I sent the second sample in but plugging the numbers into the calculator it was 35.23 so if nothing else, I'm pretty consistent.
It has been about 27 hours since I mixed the water. I topped off the buckets with fresh water to bring them back to 1.026 (fresh calibration on the refractometer) and then checked them with the Coralife hydrometer (swing arm type) and got 1.027. New bottle of alkalinity reagent (HI772S) arrived today so I grabbed it and a new curvette and retested samples from a different bucket than yesterday.
Alk - 9.6 (171)
Ca - 500+ (didn't bother refilling syringe to see exactly how high it was)
Mg - 1560
Last time I sent in a Triton sample I dumped the results into a calculator which indicated a salinity of 35.26 (1.0266) where I had measured 1.025 with the refractometer at the time (pretty sure I calibrated it at the time but that was indicated in my notes) so I don't have much reason to suspect my instruments and/or calibration solution is to blame.
To compound the issue...
Samples collected 8 July
My results/Triton
Ca 420/456
Mg 1335/1356
Samples collected 11 Aug
My results/Triton
Ca 435/460
Mg 1350/1371
My results were lower than the Triton analysis on both samples. I didn't note salinity when I sent the second sample in but plugging the numbers into the calculator it was 35.23 so if nothing else, I'm pretty consistent.