hydrometer accuracies observations

[treesprite]

Now that I have a refractometer at home, I know if all these swingarm hydrometers are accurate of not. Upon learning that the Coralife Deep Six I have is accurate, I took it to work to replace an old one that wasn't.

 

Please share your observations on brands if you have any. These are mine:

 

Coralife Deep Six - have had it several months and it matches the refractometer. I like the design of it.

 

Marineland Labs Instant Ocean - both brand new: #1 read sg about .02 - .03 too high, #2 read sg about .02 too high. Nice design but that doesn't make up for accuracy.

 

Marine Enterprises - #1 only a few months old is accurate, #2 that was used for a couple years sticks a lot so accuracy varies. No-frills design.

[lanman]

I only ever had a 'deep six' before I got my refractometer. It read very low - I thought I was running my tank at 1.025. When I got the refractometer, it turned out to be 1.031. So I guess it was reading .06 too low.

 

bob

[treesprite]

I only ever had a 'deep six' before I got my refractometer. It read very low - I thought I was running my tank at 1.025. When I got the refractometer, it turned out to be 1.031. So I guess it was reading .06 too low.

 

bob

 

Wow, that's seriously bad - I guess I got lucky with this one then. I wonder if the manufacturers even have quality control on these things?

[HowardofNOVA]

Forrest,

Your readings where the exception and not the rule with the Deep6, I had one that read alot like Bob's!

When we did a GB for Refractometers a while ago, everyone posted what their hydrometers read when they got their units and ALL where off,most by a couple of units!

[amay121]

What is it about Deep6's. I had the same issue 1.025 was really 1.031. I had to slowly decrease the SG and that was painful.

[treesprite]

Interesting info about it. I'm still interested in knowing what kind of quality control these manufacturers are using if any. I'm sure if using more would make the product more expensive there are plenty of people willing to pay the extra.

[HowardofNOVA]

With the cost of Refractometers running around $50 or less, best to go that way. Bottom line, it works!

[treesprite]

With the cost of Refractometers running around $50 or less, best to go that way. Bottom line, it works!

 

Problem is that for some people - like me - even that puts a refractometer lower on the list, however that was with not realizing how inaccurate they really can be. Also for me personally that goes with teh fact that I didn't even know there was such a thing as a refractometer until about a year ago after 10 years with a fowlr. Refractometers should be sold in the stores alongside the hydrometers (thinking general pet stores that real casual hobbyists buy from).

Edited May 19, 2008 by treesprite

[amay121]

That's probably not going to happen because it's not inventory that moves fast enough to carry. People typically carry their refractometers for years on end.

[Highland Reefer]

I had an Aquarium Systems Sea test Hydrometer that read accurate for years. I used it for quick testing and then verified with a refractometer. Unfortunately, it fell apart on me and I bought a Deep Six. It is off by 0.003 on the low side. I find that it is consistant and am still able to use it as a quick test, but like you are saying, if someone is unaware that it is off, they could get in trouble with it. Like Howard says, you need to purchase a refractometer and calibrate it properly.

 

The aquarium industry has the same problem with all the testing products. Some of the pH kits are not even close to the real pH. The authors in the marine industry say that the test equipment is close enough.