Ok so i broke down and bought one. It said to calibrate it with RO at 69 degrees? Ok but my tank water is 80. So i just put some ro on it and didnt need to turn the calibration screw at all. I put a sample of tank water on it and its reading 1.23. With the hydrometer im at 1.25. Man i dont know if i should add some salt or not? Ideas?
refractometer help
- Thread starter crankbait
- Start date
Augustus
New member
I would trust the refractometer. Mine did not require any adjustments out of the box either and I find hydrometers hard to read on a good day.
If you are still in doubt check a sample then have your LFS or someone else with a refractometer test the same water and compare results.
If you are still in doubt check a sample then have your LFS or someone else with a refractometer test the same water and compare results.
dwd5813
New member
dwd5813
New member
Millticket
New member
+1 on the calibrating with solution vs. ro/di. I recently did that to mine and discovered my tank was actually 1.026 instead of 1.025. Not a huge difference, but I feel better knowing I have an accurate reading.
fishgate
Active member
I hear what you are saying, but the directions specifically state to use RO water. Why would they state that if calibration fluid is better? You'd think they would want you to buy the calibration fluid and hype that up. I've always use RO water and set the refractometer at "0".
Even though we use refractometers in our hobby they are also widely used in other industries and calibrating them with ro water is more appropriate for most application except our hobby. It is better if you calibrate it using a solution that is close to the SG that we use. Calibrating with ro water is going to give you a bigger deviation by the time you get up the scale to our SG. By calibrating with a standard solution you remove much of that error.
The directions and the refractometer itself are specifically made for folks testing brines (at least for all but a couple of those sold to hobbyists), not folks testing seawater. RO/DI calibration is fine for testing brines, but not seawater (at least not in most cases). The actual manufacturers of most refractometers probably do not even know what we use them for. So you should always use a seawater standard.
fishgate
Active member
The directions and the refractometer itself are specifically made for folks testing brines (at least for all but a couple of those sold to hobbyists), not folks testing seawater. RO/DI calibration is fine for testing brines, but not seawater (at least not in most cases). The actual manufacturers of most refractometers probably do not even know what we use them for. So you should always use a seawater standard.
I got mine from Marine Depot and it is their own branded model. Oh well. It seems accurate enough for me with RO water. Maybe one day I'll get some test solution and check it to see just how accurate that is.
Well, it is guaranteed inaccurate in that case, but not by all that much since our reef aquaria are quite forgiving of salinity variations (luckily for us).
