hydrometer

[EB847]

suggestions for a decent accurate one?

 

[Anonymous]

Spend the extra few bucks and get a refractometer. This is not top of the line one but better than a plastic swing arm hydrometer.

http://www.premiumaquatics.com/Merchant ... Hydrometer

 

[Rob Top]

Plastic swing arms tend to be very inacurate. If you don't get the refractometer now you will wind up spending that much in replacing the glass ones you brake

 

[das75]

Just wondering what's not accurate with a swing arm. Is the calibration, repeatability etc?

Could I compare one to a refractometer then add a correction or offset?

 

[Anonymous]

I do not know if it is true for all, but I found mine to give me repeatable results. I had it calibrated to a refractometer. The deal with the swing air is if they are not manufactured just right then they will be off. If the arm is a little to big or small it will throw off the reading. Also if they are not assembled just right the reading will not be correct.

 

[ChrisRD]

Whatever you choose, I would check it with a reference solution before trusting it. See Randy's article:
http://reefkeeping.com/issues/2004-06/rhf/index.php

When using a swing-arm type hydrometer you need to make sure there are no tiny air bubbles sticking to the arm - that will throw off the reading.

Refractometers are relatively cheap now and they're easy to use so I prefer them over hyrdometers these days.

HTH

 

[travisurfer]

i got a refractometer for $30

 

[Anonymous]

i found one cheep on ebay. there was a big supplier that makes them for everything. if you do a search make shure the one you get automaticaly compensates for temp. there like 5-10 more dollars but worth the hastle.
here is the ebay item number for the one i got. they have a store and somtimes you can pick one up real cheep like i did when they put them up for bid.......
7598266085

 

[comatose]

Just wondering what's not accurate with a swing arm. Is the calibration, repeatability etc?

Could I compare one to a refractometer then add a correction or offset?

refractometer is the only way to go, with swing arm they may be accurate at first, but over time calcium or salt buildup on the arm decreases their accuracy.

 

[Mihai]

I was very happy with my swing arm hydrometer! I did indeed get very repeatable and sensitive results. I can't tell you if they were also precise as I never calibrated it. As everybody seemed happy at 1.025 I kept it there and nobody complained. I recently (2 days ago) had to part with it, so I got a new one - same company Coralife.

The problem with the new one is that, for whatever reason, bubbles cling to the arm and the results are wildly off. If I can manage to get rid of all the bubbles, it's accurate again. I can't tell you why my previous one never had the problem with the bubbles (perhaps a coat of slime or oil?!), but I hope that the new one will get rid of this problem soon, or I'll buy myself a refractometer.

M.

 

[Rikko]

After I got my refractometer I tested about a half dozen hydrometers in the store I worked and friends and whatnot.. All hydrometers were accurate - some were never even cleaned. The "worst" one I found was 0.001 higher than the refrac.

 

[fishaddict]

best hydrometer is the one you don't get.

 

[Anonymous]

best hydrometer is the one you don't get.

:lol: True