Hydrometer

[Sean_Buckley]

Is the floating kind of hydrometer very accurate? Its the kind that has the numbers on a small tube and the higher the salinity (or is it SG, or are they basically the same?) the higher it floats, the higher the SG shown on the tube.
Sean

 

[steelhealr]

They are considered very accurate...if you want to suffer the same fate as the bobbing thermometer in the FW tank. Spend the money on a refractometer. You won't regret it. SH

 

[Sean_Buckley]

So, not very accurate at all, then? What about the kind that you put water into and the needle shows the SG? I don't know if I have the money for a refractometer...I'll have to check it out.
Sean
EDIT: I looked at some refractometers online and they aren't as expensive as I thought. But do I actually need one, or would the hydrometer with the needle work well enough for me? I plan on having some corals.

 

[fraservet]

I like the floating hydrometer.
Like any other type, it is not the accuracy that is vital, it is the consistency.
Really there is a reasonably wide range of SG that people have their tanks at.
If the hydrometer is .005 out, then it doesn't matter - so long as it is 0.005 out every time (which it should be).
One important thing is not to put it in the tank to measure sg. get a jug, fill it with tank water and let it settle for a minute, then measure.

- the needle hydometers have a reputation for getting stuck
- you can get a refractometer for around £30, but they do not necessarily give an accurate reading either.

 

[maestro]

I like the floating hydrometer.
Like any other type, it is not the accuracy that is vital, it is the consistency.
Really there is a reasonably wide range of SG that people have their tanks at.
If the hydrometer is .005 out, then it doesn't matter - so long as it is 0.005 out every time (which it should be).
One important thing is not to put it in the tank to measure sg. get a jug, fill it with tank water and let it settle for a minute, then measure.

- the needle hydometers have a reputation for getting stuck
- you can get a refractometer for around £30, but they do not necessarily give an accurate reading either.

[snapback]853668[/snapback]​

If buying a hydrometer you need on ethat shows what temperature it was calibrated at, most of teh cheap ones dont.

For example if yours was calibrated at 10c and your measuring water straight out the tank at 25c then it wont give you an accurate reading.

The tmc precesion hydrometre is calibrated at 25C and extremely accurate

 

[JJ1234567]

I bought my refractometer off of ebay for 40$ and it auto adjusts to temp. I had a hydrometer for all of three days. The first time you get even the smallest ammount of air bubbles under that swinging arm your reading is going to be off.

Look at it like this. Marine is by far the most expensive type of fish tank to set up. When your talking a few hundred dollars (depending on size of tank and choices) of live stock for your beautiful new tank...wouldnt you want to spend the extra 34 (+shipping), to get a very accurite reading on their living enviroment?