Is it possible that low magnesium is causing my problems?

I didn't want to jump the gun and say that API is bad. Even though the values were different, they weren't extremely off IMO and indicated the same general problem.

 

sounds like a good plan but are you aware the marked lines on the vials of the api test vials are incosistant?Out of eight tubes,I have 4 that are incorrect which would lead to false readings.Filling the vials with a medical type syring at 5ml will get you more accurate test results regardless of wheather the water is on the vial line or not.Also,yes,get a refractometer,i still use hydrometers for "spot checking" but back it up and test the accuracy of my hydrometer with my refractometer.One of the best buys i've ever made.

 

I just double-checked my solution bottles and they all show expiration dates in 2014 or 2016or manufacture dates in 2011.

 

Yes, I noticed the different line levels some time ago and and purchased test tubes with "rubber" stoppers, API's are crap, and use a medical syringe to draw up the 5ml.

 

His refratometer reading is one that I cannot argue with, not only does he calibrate it with RO/DI, he also uses control samples at three different levels that he gets from a lab at the University of Missouri.

 

Good deal,and while i don't want to advocate that api's are the best kits out there,i think many fill to the line and this is a big reason api kits get bashed for being crappy kits.

 

I am good with the reference samples but the use of RODI is not as reliable as using known references.