Hyrdometer to use???

[Delphinus]

Well .... I have used the plastic box swing arm types and the one thing they are good for is that they are automatically temperature corrected.

That said. Have you ever taken any two of these and gotten a consistent reading on the same sample of water? You'd be VERY surprised the range of error on those plastic swing arm types.

I personally like the glass plumb bomb type, but you have to take temperature into account to determine your salinity from SG. But with THAT said .... I tend to go through many of these per year because they are fragile and I always break them sooner or later.

The real cream of the crop is the refractometer types. These kind of look like a flashlight. It's actually more like a rudimentary microscope. You take a drop of water, place it on the glass plate, and look through the other end (pointed at a light source). The water bends the light based on the SG, and you read the value of a scale on the eyepiece. Nice, but expensive compared to the other options. And I think you still need to temperature correct.

I've never seen a digital hydrometer. I can't imagine those would be anything inexpensive....

[ 29 April 2002, 13:35: Message edited by: delphinus ]