Originally Posted by Dogstar
The only way to know how accurate a hydrometer is, is to compare it with one that is known to be properly calibrated and accurate.....most cheap plastic ones mass produced for the hobby are not calibrated very well and the ones that are, need to be properly maintained...some of the glass ones are a little better....How can anyone know if any testing equipment is accurate if its not compared to something that is known to be....even refractometers can be wrong if not compared or properly callibrated....this even goes for test kits as well.....
Lower salinities to prevent parisites can only help some, for fish only systems....typical reefs including corals and inverts need a salinity closer to natural seawater levels, IMO
Yep, I agree with dogstar. If it is fish only you can get away with a hydrometer, but if you have a reef, definately invest in a refractometer. It costs way less than coral replacement.