A really bad idea

buildinboats · 11/03/2007, 06:30 PM

After reading about the inaccuracies of swing arm hydrometers I had a great idea. I'd bring mine on a trip to the barrier reef in Belize and calibrate it out by the reef. I kept it inverted while submersing it down several feet from the surface and then let it flood. i then lifted it out of the water to read it. I redid this test 3 or four times, each test with the same result. I marked the hydrometer where the swing arm floated, at 1.027. I felt pretty clever to have corrected the hydro.

Fast forward 5 years and hundreds of gallons of water changes later. I bought a refractometer, checked it's calibration and then tested the tank. 1.031, unbelievable!

sjm817 · 11/03/2007, 07:17 PM

Quote:

Originally posted by buildinboats
I bought a refractometer, checked it's calibration

How?

buildinboats · 11/03/2007, 07:40 PM

The refractometer is brand new. I used RO/DI water which I've read is unreliable. It read 1.000 on the nose. I've ordered some Pinpoint 53 mS solution so I'll soon see if there's a difference.

sjm817 · 11/03/2007, 07:42 PM

Wait until you check it with the proper calibration fluid before you change anything.

11/03/2007, 06:30 PM	#1
buildinboats Premium Member Join Date: Apr 2007 Location: Shelter Island, NY Posts: 369	A really bad idea After reading about the inaccuracies of swing arm hydrometers I had a great idea. I'd bring mine on a trip to the barrier reef in Belize and calibrate it out by the reef. I kept it inverted while submersing it down several feet from the surface and then let it flood. i then lifted it out of the water to read it. I redid this test 3 or four times, each test with the same result. I marked the hydrometer where the swing arm floated, at 1.027. I felt pretty clever to have corrected the hydro. Fast forward 5 years and hundreds of gallons of water changes later. I bought a refractometer, checked it's calibration and then tested the tank. 1.031, unbelievable!

11/03/2007, 07:42 PM	#4
sjm817 On Yer left! Join Date: Sep 2004 Location: Northern VA Posts: 18,777	Wait until you check it with the proper calibration fluid before you change anything. __________________ - Scott

11/03/2007, 07:40 PM	#3
buildinboats Premium Member Join Date: Apr 2007 Location: Shelter Island, NY Posts: 369	The refractometer is brand new. I used RO/DI water which I've read is unreliable. It read 1.000 on the nose. I've ordered some Pinpoint 53 mS solution so I'll soon see if there's a difference.