How are you determining the change in consistency over time, would be interested in your procedure if you would like to share it...
Thanks
Rick
Getting different results with consecutive tests, I believe it is from the diode/sensor reading the wavelength wearing out.
all cuvettes are always rinsed and stored with ro/di
procedure:
1) Fill cuvette so bottom of the meniscus lines up with 10 mL mark when sat on a level surface.
2) close cuvette, dry off, then Wipe any fingerprints off with Kim wipe
3) drop cuvette in tester with “10 mL” mark facing the front (side with screen and button)
4) blank read
5) remove cuvette (not touching the center of it at all) add reagent packet, start timer and shake until powder is dissolved.
6) place cuvette back in tester in the same orientation with 10 mL mark facing the front
7) get result
My degree is in marine biology and I worked at my university’s Finfish research facility after graduation for a few years. Lots of water testing with spectrophotmetry for the grants we were working on, so I’m confident in my testing procedures. I now do aquarium installation and maintenance full time with about 175 customers.
The Hanna testers can be nice, but have their drawbacks. They’re affordable being colorimeters, but hitting high quality hardware at that price point can be hard. It’s very convenient having a digital readout. I think people just want to believe it because it spits out a number on a digital display, which seems more definitive than determining the exact point a color changes on a simple titration test.
edit: I will add, I’ve gone through probably 20 of the salinity pens at this point too, nice when they work, but like to error out, drift, lose calibration, etc.