Hydrometer

[Firstman]

Any suggestions on a good hydrometer

[Jonthefishguy]

Choose a refractometer instead. Hydrometers are not always accurate and differ by .02 up or down. Temperature also plays a role in this. Hydrometers can give misreadings based on the temperature of the water.

[Firstman]

thanks I will look into that. my hydrometer is always reading diff. I dont like it anyway.

[g-ray]

It may be reading diff. depending on when you test it because as water evap. your salinity goes up.

[tony]

ive owned the marine depot $30 refractometer and a more expensive milwaukee unit and can tell you with a fair amount of certainty, they are the same

make sure you get calibrating fluid and calibrate it regularly though

[Bill S]

OK, everyone gets mad when I say this. But, remember, I've been doing this for over 35 years...

Do NOT own a refractometer, without a good hydrometer. A good floating hydrometer (good = one calibrated for reef temps) is absolutely indespensible. A good one only costs $15.

Yup. I STILL don't own a refractometer. Ask me how many times I've had a good hydrometer be wrong or know someone that got a bad reading? NONE. How many folks do I know that have nuked or severerly damaged a reef tank with a refractometer? DOZENS.

A good hydrometer's reading - right or wrong - is ALWAYS repeatable (if it is off, it's always off by the same amount) A refractometer. Not so much.

[princer7]

Bill, where do you find the floating hydrometers? I was thinking this might be a good thing to keep in the sump. Always worried about the skimmer pulling out too much and as my top off water is unsalted R/O water.

[Bill S]

PS. John, I generally agree with you on most topics. BUT. .02???? No way. That's essentially off by +/- 100%.

.002? maybe. But there is NO WAY that it's .020. In fact, specific gravity of seawater goes down .002 from 68 to 77 degrees (20 to 25C) or .0002 per degree. Frankly, IF temperatures are pretty much constant, a hydrometer is COMPLETELY repeatable - thus the beauty of the simple device.

[Bill S]

Mine came from CB Pets! Uh oh...

BTW, NEVER keep one in the water. Algae, salt WILL change the readings.

[Jonthefishguy]

0.002 is what I was reffering to. Thats what I get for typing at a red light from a phone and trying to get it posted before the light turns green. You are correct. .02 is NOT correct and .002 is.

[Bill S]

Like I said - for NORMAL reef systems - maybe a 5 degree varience between high and low - a hydrometer works FINE, and best of all - it's REPEATABLE. That means that once you decide it's right, it' will always be right in your tank.

A refractometer, on the other hand, is notorious for slooooowwwwly getting out of calibration. And then one day, you wake up and your tank is dying!

[DrMark]

As always, stability is the key. Whatever the means to that. I like refractometers, but cant forget to calibrate them periodically.

[Aquapod24]

Mine came from CB Pets! Uh oh...

BTW, NEVER keep one in the water. Algae, salt WILL change the readings.
__________________
Bill


Thanks. That means I'd better take some vinegar to mine right away! :wink_smile:

[jroescher]

Anybody else use one of these:

http://www.aquariumsupplystore.com/Pictures/Salinity%20meter/sys_digilab_tss1.jpg

They used to be sold by JBJLighting.

[Mr Cob]

I feel I should post this so Bill can say he now knows someone that has had a bad Hydrometer 4 times in the last two years.

My hydrometers...all 4 of them slowly went bad even after I cleaned them with freshwater religously. In fact at one point my tank was at like 1.035 but my Hydrometer said 1.024. I finally realized something was wrong with the tank when corals started closing up and everything was looking bad in the tank. I cross referenced my hyrdometers with a LFS...I had two at the time and they both were reading differently and both were way off. To my surprise the LFS also had 3 that were reading differently...so between me and the LFS we had 5 hydrometers that were all reading the same water anywhere from 1.010 to 1.024...so they busted out a Refractometer and it read my water at 1.35. That was the last time I used a Hydrometer regularly for mixing salt.

I now use a refractometer and calibrate it weekly. It's been 6 months and I'm wondering what took me so long to purchase one. It was definitely worth the extra money. No more problems here!

EDIT: I'm referring to swing arms...so this post is pointless because everyone already agrees that swing arms are crap!

[alton]

Floating Glass Hydrometer user since 1982. Buy the large size not the small one. Keep it clean and store it dry.

[OrionN]

Bill,
You are wrong in state that the result we got from a refractometer is not repeatable. It is a physical characteristic of the solution so it is very repeatable. You don't have to calibrate refractometer with know solution either, I just use RO water. I know that use a know solution at or near 35 ppt is slightly more accurate but the degree of improvement accuracy we are talking about here is not important in keeping a reef tank.
Depends on the refractometer, the screw that adjust the scale can be easy to bum and turn (bad refractometer) or have to be adjust purposefully and not accidentally (good refractometer). If this screw turns easy by accident, we have to check it often, how often depends on how easy the screw turn. I had mine for 10 years and never have to adjust this. It only takes me a few seconds to check the salinity of salt when I mix them or check the salinity of the tank.
I don't have to get a large enough flask to float the hydrometer and make sure the hydrometer not tough the side, or any bubble on the device, or break a fragile glass hydrometer.
About tank crash, I don't think anybody who use a refractomer have their tank crash due to this device, while I know several had their tank crash due to one of those swing arm hydrometer.

While it show that you are a good reefer, and that you do not need a good hydrometer or refractometer to keep reef tank, you have not have a tank crash is immaterial in the decision of buying a hydrometer or refractometer.

In deciding whether to get a good hydrometer, bad hydrometer or a refractometer, the refractometer wins every time IMO. Accurate, easy and quick to measure salinity of tank or water mix, easy to care for, takes abuse well and in expensive when compare to a good hydrometer. Bad hydrometer is a no no, and a good hydrometer is to difficult to care for, does not take abuse well and troublesome to use.

Regardless of device we use, we do not need to be that accurate in keeping the salinity of the tank, only that it need not to change too fast, I make sure that water change I used is at least as warm as the tank and the salinity matched. Most animals will be fine between 30 ppt to 40 ppt provide that it does not change from 35 ppt to 40 ppt in a few minutes
BTW, who do we know that wasted their reef tank due to a bad refractometer?

[DrMark]

I think most, but not all, agree the swinging arm plastic hydrometers are trash.
There are high quality glass hydrometers that, when cared for correctly, will yield good repeatable results.
As I said, I am in favor of a good refractometer calibrated routinely with RO/DI water as Minh said.
mark

[Mr Cob]

I should note that I was referring to swing arms. I have used glass floating hydrometers that also read temp and have not had any problems with them. I actually keep one in my sump but it is hard to get a precise reading from it...I just look to verify it's floating in the green zone...LOL.

I also didn't know that it wasn't wise to keep it in water. Crap, I thought that was the purpose of it. Guess I'll pull mine out. :(

[Bill S]

Rob, swing arms are NOT hydrometers. At least not for use in a fish tank... I believe they are responsible for killing more fish/corals than any other piece of equipment. A GLASS hydrometer - the large 12" ones - are real hydrometers.

YES, if you calibrate your refractometer, it is a great instrument, and accurate. THAT is the big deal - even the best forget to calibrate.

Mihn, I don't want to name names... To protect the guilty.

[Mr Cob]

Rob, swing arms are NOT hydrometers. At least not for use in a fish tank... I believe they are responsible for killing more fish/corals than any other piece of equipment. A GLASS hydrometer - the large 12" ones - are real hydrometers.

YES, if you calibrate your refractometer, it is a great instrument, and accurate. THAT is the big deal - even the best forget to calibrate.


Yes, I responded with my clarification that I was refering to Swing Arms and noted that everyone else was refering to glass hydrometers...12" ones, which I have, and to this day have not ever had any problems with them. My only new problem with the glass version is that everyone is saying they should be stored dry. I really liked having it float in my sump to view any time I need. Should have guessed that was too easy!:angel:

My other problem, with refractometers, is calibrating...it's annoying. Seems nothing can just be "plug and play".

[OrionN]

Out of habit, I calibrate my refractometer when ever I mix salt. So long now it always come out perfect that I never have to adjust it from day 1. I even lost the tiny screwdriver that come with it to adjust it with.
In case anybody wanted to know, I have a
Milwaukee MR100ATC Refractometer.
It come with a box lined with styrofoam cut out for the refractometer, a plastic pipet and a small screwdriver to adjust it with.
I used glass hydrometer when I first got into marine tank and broke more than my share of those expensive hydrometer. I consider getting a big enough flask for my hydrometer, keep it floating away from the wall and make sure there are no bubbles on the hydrometer a pain in the behind.
Calibration, to me just another read that take a few seconds and that is all, mainly just to reassure me that I got a good refractometer.

[OrionN]

Rob,
This refractometer is as close to plug-and-play as you can get for refractometer.
A quick search show that you can get this refractometer for anywhere between 60-90 dollars