Is This An Ok Hydrometer To Use

[Fella]

Do fish have hydrometers that precise too?

Probably not for salinity, but certainly for other dissolved minerals. Salmon and trout supposedly find their way from the sea to a particular stream my tasting the exact mineral composition of the waters they were born in. It's pretty mind boggling really.

When I use a hydrometer, the trickiest thing I find was to remember to wash it immediately before and after using it.

Someone needs to write a pinned topic on how to use these things. As you say, there are tricks to remember.

Cheers, Neale

My dad is a keen angler and frequently travels to Ireland where he fishes for sea trout, brown trout, pike, salmon etc. He really couldn't give 2 hoots about fishkeeping, but he said it was an amazing sight to see fish returning into the lough from where they originated. They have a bridge over the mouth of the lough and you can actually see the fish returning through the comparitively small gap (small when you consider the size of the ocean).

There is also a place in england (it might be many places, I remember this from an attenborough wildlife show some years ago) where eels and elvers travel only when there is a full moon up across an "eel stairway" or something similar, much like how salmon have particular sections of rivers dedicated to their free travel. Can anyone shed any light on this, or am I simply confused?

Sorry for the thread hijack!

 

[chishnfips]

Why are you soaking it?

You don't calibrate it. It comes calibrated to a specific temperature, e.g. 25C. It should say on the device or its packaging. If you use one calibrated to 25C at 15C, it will give an inaccurate result.

Cheers, Neale

How do you calibrate the temperature of the hydrometer? at the moment it is soaking for 48 hours in a bucket of salt water

Hi Neale,
It says on the packaging that I have to soak it in salt water for 48 hours when I first unwrap it to condition the meter?

 

[nmonks]

Fine. Never heard of that. Can't do any harm. Probably to wash off the solvents used in manufacturing or something. Once done, all you need to is to remember to keep it clean between uses, ideally rinsing in something slightly acidic (like soda water) to dissolve any lime and salt that builds up around the hinge.

Cheers, Neale

It says on the packaging that I have to soak it in salt water for 48 hours when I first unwrap it to condition the meter?

 

[chishnfips]

Would a vinegar and water solution do ok for rinsing it?

 

[nmonks]

Yes. Just be sure and rinse it out nicely when you're done. Vinegar (in small amounts) is harmless to fish, so the problem isn't a drop getting into the tank when you use the hydrometer. But any acid has the potential to damage the plastic. Soda water loses its acidity as the bubbles go, so it is harmless, but vinegar or lemon juice has the potential to sit there causing damage. You don't need to use the vinegar every single time, but certainly a couple of times year would be a good idea, or if the pivot thing seems to be "sticking". Most of the time, simply rinsing under the tap will be fine.

Also be sure not to use hot water when cleaning: this might cause the plastic to swell or distort.

One reason I like the cheap glass hydrometer is that, short of dropping it, they don't break easily and are chemically resistant to damage.

Cheers, Neale

Would a vinegar and water solution do ok for rinsing it?

 

[The-Wolf]

Someone needs to write a pinned topic on how to use these things.

well volunteered that man

 

[chishnfips]

cheers neale you are star

 

[rob newland]

cool, I am using instant ocean salt aswell, but how much do you reckon I should add to a 180 litre, to make it 1.005? a table spoon or something?

Haha sorry that made me laugh. Did you mean a tablespoon per gallon?

 

[vic]

I would suggest that one visit a wine making shop. Hydrometres are used in wine making to determine the sugar level in the must. These hydrometres are quite accurate. The one I have goes from 1.000 to 1.010 in increments of .002 to a top point of 1.170. Each .010 range is split in .002 increments. Will result in the ability to very accurately measure the SG of the tank water and from there determine the needs of the tank to adjust to the required salinity.
Vic

 

[Fella]

I would suggest that one visit a wine making shop. Hydrometres are used in wine making to determine the sugar level in the must. These hydrometres are quite accurate. The one I have goes from 1.000 to 1.010 in increments of .002 to a top point of 1.170. Each .010 range is split in .002 increments. Will result in the ability to very accurately measure the SG of the tank water and from there determine the needs of the tank to adjust to the required salinity.
Vic

I saw a glass hydrometer for sale recently for wine and beer homebrewing, can they really be used for measuring salinity in tanks? I would have thought they would have measured different things?

 

[chishnfips]

cool, I am using instant ocean salt aswell, but how much do you reckon I should add to a 180 litre, to make it 1.005? a table spoon or something?

Haha sorry that made me laugh. Did you mean a tablespoon per gallon?

ha ha no, I was being serious lol. Ok then so how much should I add to make it 1.005? I dont know how potent the salt is.

cheers

 

[nmonks]

No, a hydrometer is a hydrometer is a hydrometer -- they all measure density. You could use them to measure the density of mercury or petroleum if you wanted: what they do is compare the density of the liquid they are in against pure water at some calibrated temperature and air pressure.

Your issue with a brewing hydrometer will be whether it is calibrated to 25C and whether the scale is adequate for reading to "thousandths", i.e., 1.001, 1.002, etc. Assuming the answer was yes to both of those things, and it was a reasonably well-made device, it would be fine for keeping brackish water fish.

Cheers, Neale

I saw a glass hydrometer for sale recently for wine and beer homebrewing, can they really be used for measuring salinity in tanks? I would have thought they would have measured different things?