[eddiedellz]

I have a instant ocean hydrometer and i was a little nervous if its giving me the correct reading so i bought a redsea hydrometer and low and behold they read two diffrent things verry fusterating

[jimw369]

You want a refractometer. Not a hydrometer. Much more accurate.

Originally Posted by eddiedellz

I have a instant ocean hydrometer and i was a little nervous if its giving me the correct reading so i bought a redsea hydrometer and low and behold they read two diffrent things verry fusterating

[Tonz of fun]

I bought my refractometer from Marinedepot.com for 50 bucks.

[swinginbeef]

read the directions. Some hydrometers are 'dialed in' at 60 or65° and some are set for temperatures around 80° like we tend to keep. If your water temp is not the same as the temp that the hydrometer is set for, there is a conversion factor. For instance if your tank is 80° and the hydrometer is set up for 60 or 65° water and your water tests out at 1.022, then your actual SG is right around 1.024ish.

Look in the instructions that came with the hydrometer.

[pogodzib]

Hydrometers are known to be inaccurate, but consistent. If you buy 3 of the exact same hydrometers from any of the major brands, you'll probably end up getting different readings on all three. Refractometers are much better. Sine you already have hydrometers, you have two options besides for buying a refractometer. The first option is to find someone that has a refractometer and see how your hydrometers compare to the refractometer. If your hydrometer reads 0.005 SG higher (which is very common) than the refractometer, then you're hydrometer will read 0.005 SG higher all the time (assuming that your testing the water at the same temp as the tank's water). The second option is to just assume the one of your hydrometer is accurate (of which it probably isn't) knowing that a consistent salinity is just as or more important that having the optimum salinity.