Hydrometers

[eel]

I've set up another tank for my son as he wanted some puffer fish, so the other week I have got 3 Figure of 8 Puffers in it. At the moment they are in fresh water but I know I will start having to add some salt in the tank to make it brackish. I know I will need a Hydrometer to test the gravity of the water and wanted to know would a Hydrometer for making beer be any good as I have one at home but don't know if they have the same readings on them. The readings on it go from 90 - 1100 SP.GR. Is this any use?

 

[nmonks]

In theory you can use a good brewer's hydrometer provided it has sufficient accuracy within the range 1.000 and 1.030. Brackish water will be somewhere between 1.002 and 1.012 at 25 C depending on the species being kept. But frankly, for the sake of a fiver you'll probably find a floating glass hydrometer more convenient.

Cheers, Neale.

 

[eel]

In theory you can use a good brewer's hydrometer provided it has sufficient accuracy within the range 1.000 and 1.030. Brackish water will be somewhere between 1.002 and 1.012 at 25 C depending on the species being kept. But frankly, for the sake of a fiver you'll probably find a floating glass hydrometer more convenient.

Cheers, Neale.

Thanks for your reply
The Hydrometer is a floating one but I shall look at the ones in the fish shop.

 

[nmonks]

You could always make up some seawater -- 35 grammes of marine salt mix per litre -- and see where the hydrometer you have comes out to. At 25 C, it should register SG 1.025 or thereabouts. If it's within, say, 1.024 and 1.026, that's good enough for brackish water fishkeeping. Temperature is a key factor though, so cooler or warmer water won't work. Try my Brack Calc tool to see how temperature, salinity and specific gravity are related.

Cheers, Neale

 

[eel]

You could always make up some seawater -- 35 grammes of marine salt mix per litre -- and see where the hydrometer you have comes out to. At 25 C, it should register SG 1.025 or thereabouts. If it's within, say, 1.024 and 1.026, that's good enough for brackish water fishkeeping. Temperature is a key factor though, so cooler or warmer water won't work. Try my Brack Calc tool to see how temperature, salinity and specific gravity are related.

Cheers, Neale

Thanks again Neale this is really handy info

 

[nmonks]

Glad to help. Cheers, Neale