Premium Aquatics Refractometer

Scubabum · Mar 17, 2015

I received my new Refractometer from Premium Aquatics yesterday. After reading several posts I calibrated my Refractometer using a 35ppt calibration fluid vs calibrating at zero using RO/DI water. (The included instructions say to calibrate to zero using RO/DI water) After calibrating to 35ppt my reading of RO/DI water which should be zero is reading 5ppt. Not sure if this is normal. I just want to be sure before adjusting the salinity in the tank.

Randy Holmes-Farley · Mar 17, 2015

Scubabum said:
I received my new Refractometer from Premium Aquatics yesterday. After reading several posts I calibrated my Refractometer using a 35ppt calibration fluid vs calibrating at zero using RO/DI water. (The included instructions say to calibrate to zero using RO/DI water) After calibrating to 35ppt my reading of RO/DI water which should be zero is reading 5ppt. Not sure if this is normal. I just want to be sure before adjusting the salinity in the tank.

It is normal for a brine refractometer (which are most often used in our hobby) to read nonzero when testing RO/DI after properly calibrating to a seawater standard. 5 ppt is a lot, however. It should read off by 1.7 ppt.

However, as long as you trust the calibration standard, that is the way to go with any refractometer that can read it. You won't be using it for fresh water measurement.

Scubabum · Mar 17, 2015

Thanks Randy. I'll trust the calibration at 35ppt. Just wanted to make sure. I've been using a Hydrometer and was shocked on how high my salinity is. It measured 42.5ppt with refractometer and was reading 33ppt with hydrometer. I'm kind of worried as I have a Reef Cleanup crew arriving tomorrow.

Randy Holmes-Farley · Mar 17, 2015

Go with the refractometer, and you can make your own 35 ppt standard if you have a scale and table salt.

Scubabum · Mar 17, 2015

Randy Holmes-Farley said:
Go with the refractometer, and you can make your own 35 ppt standard if you have a scale and table salt.

Thanks Randy. I saw your post about this. Thanks you, Great information. I shot Premium Aquatics an email today and they said they have had a bottle or two have some bad numbers. They are shipping me a couple of new bottles of the calibration solution. I received the second part of my order today which was my replacement t5 bulbs. Upon opening the package I realized I ordered 4 T12 bulbs. AAAAAARRRRRRRGGGG!!!!!!!! I can't catch a break today, LOL, Thanks for all the help.

Randy Holmes-Farley · Mar 18, 2015

Scubabum said:
Thanks Randy. I saw your post about this. Thanks you, Great information. I shot Premium Aquatics an email today and they said they have had a bottle or two have some bad numbers. They are shipping me a couple of new bottles of the calibration solution. I received the second part of my order today which was my replacement t5 bulbs. Upon opening the package I realized I ordered 4 T12 bulbs. AAAAAARRRRRRRGGGG!!!!!!!! I can't catch a break today, LOL, Thanks for all the help.

We all make those types of screw ups over time. At least this one didn't end with water all over the floor.

Scubabum · Mar 25, 2015

Contacted Premium Aquatics and they shipped me a couple of replacement calibration fluid bottles. Turns out the original bottle I received was bad. All is well and I'm loving the precise measurements I'm getting with the Refractometer.