Any Floating Hydrometers For Brackish?

[penguinpimp1990]

I hate using the regular hydrometers (although they are reliable and accurate) so I was looking for a floating one, does any one have a link or own one? I know about the tropic marin one but its sg measurer has a minimum of 1.018, like most floating hydrometers do.

 

[Little Fish]

I hate using the regular hydrometers (although they are reliable and accurate) so I was looking for a floating one, does any one have a link or own one? I know about the tropic marin one but its sg measurer has a minimum of 1.018, like most floating hydrometers do.

I was shopping for a hydrometer quite a while ago but all I could find from aquarium stores, floating or needle types, start with either 1.010 or 1.018. Except for the Instant Ocean needle type that starts with 1.000. I ended up with a refractometer. Personally, I think it is more accurate and easier to read. However, if you want a floating type hydrometers with low ranges, you may try brewery supplies or lab equipment. The following link is a lab equipment store. They have more than a hundred floating hydrometers. Some have wide ranges and some have narrow ranges. Some are marked "for liquid heavier than water" and some seemed to target petroleum. Some cost over $200 and some less than $20. I can't make head and tail out of which one can be used for our purposes.

http/vwrlabshops.com/category.asp?c=1443...hcd2=1132697742

 

[penguinpimp1990]

id like a refractometer but they are so expensive, id rather use my old hydrometer. But if i happen to get one how long do they work for? one guy i know said he replaces his every 7 months or so

 

[nmonks]

I'm confused on what is a floating hydrometer versus a regular one. To me, the swing arm, plastic box ones are the 'specials', and the 'regular' ones are the ones you put in the aquarium that look like old fashioned thermometers.

Either way, in my experience neither is terribly accurate. The two marine fishkeepers I know and trust both use refractometers. I've seen people bundle together 5 floating arm hydrometers with a rubber band, dip them in the tank, and get 5 different readings. So I wouldn't go out of my way to replace one with the other unless I had money to burn.

Having said this, they're plenty good enough for brackish water aquarium, where an error of 10 or 20% is going to make any difference. A refractometer may be a fun piece of kit to have, but it's overkill for brackish water fishkeeping.

Cheers,

Neale

I hate using the regular hydrometers (although they are reliable and accurate) so I was looking for a floating one, does any one have a link or own one? I know about the tropic marin one but its sg measurer has a minimum of 1.018, like most floating hydrometers do.

 

[Little Fish]

Having said this, they're plenty good enough for brackish water aquarium, where an error of 10 or 20% is going to make any difference. A refractometer may be a fun piece of kit to have, but it's overkill for brackish water fishkeeping.

I guess I have to agree with you that the accuracy of a refractometer might not be necessary for brackish. A 10% to 20% error is not going to make a difference. I bet the SG in their native environment changes more than that during tides or heavy rain fall or when they travel up or down stream. It all boils down to personal preference and the difficulties of locating a low range hydrometer. A refractometer cost just a little more than a good hang-on filter, to me it's worth the investment.

 

[nmonks]

Hello,

Yes indeed, for many brackish water fish, changing salinities is part of life.Fish like scats can swim directly from the sea into an estuary and up into fresh water without any ill effects. Archerfish and many puffers normally cruise around oyster reefs and mangroves, where the salinity will vary by tide and rainfall. The problem with allowing big changes in salinity isn't so much the fish but the filter bacteria.

My old marine biology professor was amazingly skilled at judging salinity by taste! He would dip a finger into the brackish water tank I'd set up in the department, and regularly get a value pretty close to what I was getting with a hydrometer.

Cheers,

Neale

I guess I have to agree with you that the accuracy of a refractometer might not be necessary for brackish. A 10% to 20% error is not going to make a difference. I bet the SG in their native environment changes more than that during tides or heavy rain fall or when they travel up or down stream.

 

[Little Fish]

My old marine biology professor was amazingly skilled at judging salinity by taste! He would dip a finger into the brackish water tank I'd set up in the department, and regularly get a value pretty close to what I was getting with a hydrometer.

I bet he was right about the salinity. It was your hydrometer that was 10% to 20% off. Just kidding I'm amazed that some people can develop such a keen sense/taste. Just like people that can do complex calculations with their heads without even pencil and paper. Our reliance on technology surely dull all our senses.