Hydrometer.

[zhewitt04]

I know I know i need to get a refracometer, but I don't and don't want to spend the money quit yet. I am currently saving for one. Anyways i got a free hydrometer in my girlfriends 29 gal Elcisple system. It reads extremely high. My current hydrometer reads my 150gal at 1.027. The new hydrometer reads off the charts. I went to my LFS to check and the old one is currect. I heard you need to cure the hydrometer. I have never heard this so was curious how and why you need to....
Also I understand that they vary in measurements and that is why i need to upgrade so please don't lecture me.....
Thanks

[Jstdv8]

is this a swing arm hydrometer or a glass hydrometer with a thermometer inside?

[Agu]

Clean it really well to remove and encrusting salt residue. If it's a swing arm type a good soak in some ro/di mixed with vinegar should do the job.

[seapug]

Some swing arm hydrometers work great, others will never give an accurate reading no matter what you do. If you're on a budget and can't spring for a refractometer, at least go for a floating glass hydrometer instead of a swingarm. The floating ones are often cheaper than the swing arms, extremely accurate and never require calibration (but you might need to compensate for temperature, so read the label)

[SDguy]

Clean it really well to remove and encrusting salt residue. If it's a swing arm type a good soak in some ro/di mixed with vinegar should do the job.

Then, ask the LFS to check your water with a refractometer. Compare this reading to your swing arm reading. The difference, IME, will be very constant, because swing arm hyrdometers, while not terribly accurate, are quite precise. Meaning, you will know the correction factor on your swing arm so that you can read the true salinity. This will hold you over until you can get your own refractometer.

[zhewitt04]

Cool thanks and it is a swing arm. I am going to look into the glass and like i said i am waiting until i get a little cash i jsut bought a RO DI unit and didn't want to tell the women i was spending another 100 on a refractometer. She would crap!

[Agu]

You can get a Refractometer (http://premiumaquatics.com/aquatic-supplies/REFRACT-PA-K.html) for about $50.

Once you clean and check calibration with a known source mark the hydrometer with a sharpie at the ideal specific gravity. That way you won't forget where it's accurate.

[Jstdv8]

the glass ones Ive found to be more reliable. and they are only like 4 bucks

[Michael]

the glass ones Ive found to be more reliable. and they are only like 4 bucks

But they break easy, however if you fill a vase with tank water and float them in that they are accurate and theres a lot less chance of breakage.

[isildursbane]

You can get a Refractometer (http://premiumaquatics.com/aquatic-supplies/REFRACT-PA-K.html) for about $50.

Once you clean and check calibration with a known source mark the hydrometer with a sharpie at the ideal specific gravity. That way you won't forget where it's accurate.

I got a little confused on this one. What is the ideal specific gravity? And how does marking it keep you from forgetting where it's accurate?

[jeff@zina.com]

I keep the tank(s) at 1.025, using a glass hydrometer with a backup of a refractometer. I really only measure when I do a water change, since with top off simplified to a fill line on the sump the salinity stays pretty accurate anyway.

By the way, I haven't broken a hydrometer in 30 years...

Jeff

[DustinB]

You can get a Refractometer (http://premiumaquatics.com/aquatic-supplies/REFRACT-PA-K.html) for about $50.

Once you clean and check calibration with a known source mark the hydrometer with a sharpie at the ideal specific gravity. That way you won't forget where it's accurate.

Or you can get one for $40 with calibration fluid: http://www.bulkreefsupply.com/store/products/test-kits/refractometer/refractometer-for-reading-salinity-w-free-calibration-fluid.html


As for "ideal" specific gravity, that's going to vary widely. Some will say 1.025 is best, others will say that the average salinity of the ocean is best(35ppt/1.0264sg). Most will say anywhere around 1.025-1.026. Personally I keep mine at 1.0264-ish.

As for the swing arm hydrometer, in normal conditions they can be perfectly consistent given proper maintenance. My deep six hydrometer is consistently .003 off. I still use mine 90% of the time out of convenience when mixing salt, though I own a refractometer and do verify from time to time. As others have stated, verify how far the hydrometer is off compared to a refractometer calibrated with a 35ppt solution.

[SDguy]

I got a little confused on this one. What is the ideal specific gravity? And how does marking it keep you from forgetting where it's accurate?

He just meant that, say you decide 1.025 is what you want. Then, you'd confirm your water is 1.025 using the refractometer. Next, you'd use the swing arm. Say the swing arm reads 1.027. Then you just mark it there, and you will always know that at that mark, with that swing arm, your water is 1.025 (not 1.027). He was just trying to save you the calculation of using a correction factor. I was confused by it at first too :)

[bertoni]

No one knows what the optimal SG is, and most likely it would vary depending on the region of origin for the species. The Red Sea runs fairly high in SG, for example. I target 1.0264, since that's the canonical ocean average, and there's no data to how that anything else is better.

[Jstdv8]

But they break easy, however if you fill a vase with tank water and float them in that they are accurate and theres a lot less chance of breakage.

Good point, I actually was in a hurry once and dropped my hydrometer in the sump for a test and I didn't float it first and it went right to the bottom and broke open.
all those little lead balls and red glue stuff all over in my sump.
Corals started shrivling up pretty bad after a couple days even after i removed the lead balls right away.

Ended up totally shutting down my sump and cleaning it out very good (found several more balls) and doing a couple of big water changes before I added new water to the sump and got it running again.
Disasterous, don't drop your glass hydrometers :P

[Agu]

He just meant that, say you decide 1.025 is what you want. Then, you'd confirm your water is 1.025 using the refractometer. Next, you'd use the swing arm. Say the swing arm reads 1.027. Then you just mark it there, and you will always know that at that mark, with that swing arm, your water is 1.025 (not 1.027). He was just trying to save you the calculation of using a correction factor. I was confused by it at first too :)

Sorry that I wasn't clear about that. Thanks for clearing it up SDguy.

It also helps when someone else is babysitting your tank. Had a person drop my SG while I was on vacation because I forgot to tell him my hydrometer was off ;). (nothing died)

[Michael]

Good point, I actually was in a hurry once and dropped my hydrometer in the sump for a test and I didn't float it first and it went right to the bottom and broke open.
all those little lead balls and red glue stuff all over in my sump.
Corals started shrivling up pretty bad after a couple days even after i removed the lead balls right away.

Ended up totally shutting down my sump and cleaning it out very good (found several more balls) and doing a couple of big water changes before I added new water to the sump and got it running again.
Disasterous, don't drop your glass hydrometers :P

yes unfortunately they are brittle, and its even more of a disaster when they break in your beer brewing barrel :lol:

[bertoni]

I broke one of mine that I had for years. I had switched to a salinity meter, but I was still upset.

yes unfortunately they are brittle, and its even more of a disaster when they break in your beer brewing barrel :lol:
Horrors! Well, if it was good beer, horrors! :)

[spslove]

I think the floating glass hydrometers are more accurate and easier to use. No need for refractometer. No calibrating for the hydrometer, mine is calibrated at 77 fahrenheit and i keep tank at 78 and mix my water at 77 so its pretty much right on. I have a refractometer as well but have stopped using after getting the glass hydrometer. I had to calibrate my refractometer every time i used it and double check, such a pain. The hydrometer is really brittle but i'm careful with it so i have not broken it yet. For sure worth $10. just my 2 cents.

[snorvich]

Clean it really well to remove and encrusting salt residue. If it's a swing arm type a good soak in some ro/di mixed with vinegar should do the job.

Amen to that. But, as you know a refractometer is really the way to go.

[tarvis]

I second that

[bertoni]

I used a floating hydrometer for years. As long as you calibrate it, it should be okay, but they're a pain to use get dirty, and you need to draw a large sample into a graduated cylinder (or something similar) to get a reasonable reading.

[JoeRonda]

Cool thanks and it is a swing arm. I am going to look into the glass and like i said i am waiting until i get a little cash i jsut bought a RO DI unit and didn't want to tell the women i was spending another 100 on a refractometer. She would crap!

Go on BigAlsonline, I got a Milwaukee Instruments Refractometer for $59.99
that's their regular price, it might even be on sale. Put in "reeftank" in the coupon code at checkout to get a 10% off discount too.....

[spslove]

I used a floating hydrometer for years. As long as you calibrate it, it should be okay, but they're a pain to use get dirty, and you need to draw a large sample into a graduated cylinder (or something similar) to get a reasonable reading.

What kind did you have that you have to calibrate it? Mine is calibrated to 25 celsius. I cant calibrate it.

[bertoni]

Well, calibration in this case just means measuring a test sample, and recording its measured value, so that you can subtract or add the relevant amount when you take a measurement. Here's an article that describes how to make a calibration solution:

http://reefkeeping.com/issues/2004-06/rhf/index.htm