Salinity meters/hydrometers

[Snaz]

At $50.00 each and as delicate a rose, this is the glass hydrometer to use if you want to measure your SG/Density to an accuracy of 0.0005

Fisherbrand* ASTM* Specific Gravity Hydrometers for Liquids Heavier than Water > ASTM: 111H; Range: 1.000 to 1.050

Hydrometer, Specific Gravity; Fisherbrand ASTM; For Liquids Heavier than Water; ASTM: 111H;Range: 1.000 to 1.050; Division: 0.0005; 330mm L; Made from polycarbonate for glass-like clarity; Use with11-582-1 Cylinder

God I love lab gear.



http://www.fishersci.com/wps/portal/...e&fromSearch=Y

[NAS]

I have a refractometer. I use it to calibrate my Sea Test Hydrometer. I have found that my hydrometer is out by .03! So, when I use it on a day to day basis i just add .03 to it and it's corrected. The real key is having the consistient salinity. That includes same salinity in the tank and water change salinity.

I re-test my hydrometer every time I do a water change just to make sure it holds.

[mark]

Remember resolution is different than accuracy.

[mike31154]

+1 on the consistency. I usually double/triple check to ensure my water change salinity is as close as possible to the display water.

Here are some photos of my measurements with the different 'instruments'.

IO Swing Arm 1.0234



Coralife Swing Arm 1.0126



Made In Taiwan Floating Glass 1.024+ (same result as refracto)

[chevyjaxon]

what about pinpoint salinity meters?

[mark]

Originally Posted by mike31154

Coralife Swing Arm 1.0126

1.0126?, good thing you cross check with the others

[mike31154]

He, he, I haven't used the swing arms for quite some time. I've been using the refracto and floating glass hydro for quite a while now. Just thought I'd bring the swing arms out and give everyone a picture... worth a thousand words I'm told.

[StirCrazy]

you know you can't add another decimal there. the swing arm measures 1.023. If you wanted to extrapulate I would say your arrow looks more like 1.0236. at any rate your accuracy is only as good as your smallest measured value. so your swing arm has a accuracy of +/- 0.001

as with anything some are better than others, I got a refractometer from a fiah store and it reads 3 decimal places like the ones here, I picked one up some where else, paid a bit more money for it and it reads 4 decimal places.

One note about floating glass type, the reading changes with changes in barometric pressure, and 3 different people will get 3 different readings off them due to the water meniscus and the angle they look at it. Oh and the break easy . I use them for making wine only, my tank gets the refractometer (well the wine might also as soon as a find a decient one that is cheep.)

Steve

Originally Posted by mike31154

+1 on the consistency. I usually double/triple check to ensure my water change salinity is as close as possible to the display water.

Here are some photos of my measurements with the different 'instruments'.

IO Swing Arm 1.0234

[NAS]

It's kinda gettin silly.

First and formost, if you test the bucket of replacemnt water and the tank water with the same piece of equipment (float, swing arm, refractomerer, picnometer what ever..) and the slainity is close or the same great!. If you tank/livestock is doing well at .024 great that means every thing is aclimated to that salinity. If its .019 and every thing is thriving so be it. It simply must be consisitent or a slow change to allow everything to adapt.

If you are having a problem, then worst case senairo take a tank water sample to a local store that has a refracometere and have them test it. Then test with your apparatus. Bob's your uncle. make the changes you need to, and re-test your corrections (for aparatus of choice) on a regular basis.

Easy.

[NAS]

That is regarless of what school of thought you subscribe to in regards to salinity level.