Inconsistent Hydrometer Readings - What brand do you use?

tbone28

tbone28

Active member
I initially bought an Instant Ocean, and my readings were inconsistent. Some days, they were high and off the charts. Other days, they were very low. So I went out and bought a Coralife one. The readings on this are different than those obtained from the Instant Ocean. However, the Coralife gives a consistent reading itself.

So what's going on?

Does it need calibration?

What hydrometers do you guys use?
 
A friend and I went through this yesterday. We tested a floating glass style hydrometer, an Instant Ocean, a Coralife, and 2 different refractometers. The Refractometers were the only consistent measurement. Samples from 2 different tanks were used.

I use to be anti-refractometer, despite having a brand new one sitting here for nearly 6 months. After yesterdays testing, I will test the hydrometer and note how far off it is. Once that note is made it will only be used in cases of emergency...IE: I break my refractometer some how.
 
I use a refractometer as well, its a good investment (around $40) as you can see the floating hydrometers can be off and inconsistent. One thing to note on using the hydrometers is that bubbles or debris can become trapped above or below the swing arm and will give you the inconsistent results, so a good tap on the hydrometer a few times should even it out a bit
 
I use a IO Hydrometer. I usually test the water about 3 or 4 times to make sure its consistant. I really need to get a Refractometer though I know..
 
the key with the Hydrometer is to first make sure it is, and stays clean. rinse it with some freshwater before and after each use. second, make sure you do not have any small air bubbles on the swing arm (unless you are using a glass hydrometer). those small bubbles will through the reading way off.
 
<a href=showthread.php?s=&postid=10928159#post10928159 target=_blank>Originally posted</a> by AquaReeferMan
Yeah, please update your current ways of salinity measurement. I didnt even know they still made hydrometers. Prevent a headache and buy a refractometer.

Check them out here.
http://www.thatpetplace.com/pet/prod/199289/product.web
Click to expand...

Is this the "recommended brand". I also checked out MarineDepot, and they have ones that range in price from $50-$120. How much should I be spending on a good quality, accurate refractometer? Why such the big gap in price? Quality or just bells and whistles?
 
The 50 dollar ones are fine. The 100 dollars ones come with a couple of more bells & whistles.

Keep in mind that some can be calibrated with distilled or ro/di and some can not. Regardless what the manufacturer claims.

The sure fire way of calibrating any refract is with 53 mS calibration fluid by Pinpoint.

My refract when calibrated with ro/di or distilled is about .003 off. Even though the manufacturer claims to use that for calibration.

I have an expensive lab grade floating hydrometer and the Pinpoint 53 mS calibration fluid measures exactly 1.0264

When I calibrate my refract with the pinpoint, then test ro/di, it reads .003 low.
 
I used the 53ms solution, calibrated once on the cheapest one from drfosters when I first got it and it has never needed to be re-calibrated, which invloved a little screw and is very easy (I have verified it at least once per month, always perfect). I could not imagine needing any bells and whisltes on that end, as I have had no need to re-calibrate anyways.

I don't know the real differences between the expensive ones, but the only thing I could imagine them adding that is useful is an internal backlight or better with differtent backlights, as with the cheapo ones, you need to find a lamp/light source that has the right angle to make it easy to read.
 
Last edited:
<a href=showthread.php?s=&postid=10932882#post10932882 target=_blank>Originally posted</a> by tbone28
So what does it take to calibrate a $50 meter?

And, does brand matter?
Click to expand...

Brand does not matter.

Pinpoint 53 mS Calibration fluid will get you right.

The manufacturer actually intented it to calibrate his electronic calcium monitor but it turns out it is perfect for refracts.

It will measure exactly 35 ppt or almost 1.0264
 
I would agree that the swing arm hydrometers should be avoided. However I think that a floating glass hydrometer is the most reliable method to use. You only need to check the calibration the first time you buy it. A floating glass hydrometer will read the same 100 years from now as it did the day you bought it. With a refractometer anything from a malfunction to bad or out of date calibration fluid can throw the readings off. A floating glass tube can't malfunction. Keep it simple and save some money in the process.
 
<a href=showthread.php?s=&postid=10933930#post10933930 target=_blank>Originally posted</a> by reefer1024
I would agree that the swing arm hydrometers should be avoided. However I think that a floating glass hydrometer is the most reliable method to use. You only need to check the calibration the first time you buy it. A floating glass hydrometer will read the same 100 years from now as it did the day you bought it. With a refractometer anything from a malfunction to bad or out of date calibration fluid can throw the readings off. A floating glass tube can't malfunction. Keep it simple and save some money in the process.
Click to expand...

Do you have any links to share so I can read up? How much do those cost?
 
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