Salinity
So this weekend I picked up a Pinpoint Salinity monitor from rebelson. Also got a lot of freebies fish food to last me another year or two!
I picked it up late Saturday afternoon and didn't get to use it because I was in a hurry to get to the NERAC dinner. Which was awesome! I got to meet Phil the Penguin and also got a behind the scenes tour of the reef setup! And I got to meet Julian and Charles as well.
So on Sunday morning I was eager to try out the new toy. I already have a
refractometer and a hydrometer (which I don't really use that much). I also have a Lab Grade
Apex conductivity probe connected which is about 6 month old. For the most part I always check my salinity and ensure SG is around 1.025. Its actually the only parameter I "test" for the tank.
Back to story, I tested the DT water with the Pinpoint Salinity monitor and it read 48.5 mS which is 1.023 SG. So I figure, no big deal, I need to calibrate the Pinpoint monitor. I got out a fresh bottle of the calibration fluid and tested it and got 56.0mS. And I thought it can't be...The Calibration fluid is supposed to be 53.0mS which is 1.025SG. So in my head i'm trying to figure out if this is the case, then what the hell is the SG for my DT!!!
I turn the screw on the salinity monitor to calibrate it down to match 53.0mS and then carefully rinse the probe and proceed to check the salinity of the DT. After two minutes it read 46.5, which is 1.022SG!!!
I got my refractometer out and calibrated it with the same solutions and got the same reading for the DT! (I should confess that I am guilty of previously calibrating the refractometer with very cold RODI water because I didn't have any calibration fluid).
LESSON LEARNED!
And the scary part in all of this is not that the SG in my DT was off. The scary part is about what is happening in my QT where I'm treating fishes with HYPO! But I'll post updates on that issue later.
Things to do:
1. Recalibrate the APEX Conductivity Probe
2. Get a few more vials of the calibration solution to double check
3. Calibrate at least once a month
4. Double check/double check
5. Figure out how to make my own calibration fluid. That little bottle of water is $8!!!