My two refracs and a hydro read way diff.

[NanoReefNovice]

I have two refractometers, one is a $100 version and the other $30 and good floating hydrometer. I set my new tank at 1.024 with my refracs which i calibrated with R/O water, they both read the same.

 

The tank has been cycling for 4 days now w/LR and I just checked it for the first time with my floating hydrometer and it reads WAY LOWER 1.016.

 

I don't have calibrating solution, its coming in the mail.

 

OH CRAP i dont know what to trust, please help!

[SmittyCoco]

You need the solution to calibrate. I would trust the hydro until you get the solution. Set it to 1.023 according to the hydro. What brand do you have?

 

Edit. Where exactly in Cali are you? I have the solution you could use?

[fayzane]

I thought refractomters were more accurate. Does your refract. self adjust to temperature? A hydrometer reading will vary depending on the temp of the room and water. My refact is designed to compensate. I'm guessing the hydometer is off.

[NanoReefNovice]

I have these refracs

http://morebeer.com/view_product/6877/1022...ctometer_w__ATC

http://morebeer.com/view_product/18739/102226/Refractometer

and this hydro

http://morebeer.com/view_product/18649/102...orrection_Scale

 

The two refracs have automatic temp compensation and I adjusted for the hydro.

 

My first thought was to trust the hydro b/c the it comes calibrated. I checked it with R/0 water and it reads 0.

 

The two refracs were not calibrated at 0 not within the correct range. However they both read the same when i check the tank water... i keep on going back an forth on which one to believe

[The Propagator]

Trust the refractometer.

Floating hydrometers, as well as swing arms can easily be off that much when you test them against a precision instrument like a refractometer. That's on the extreme end but I'd believe it. Mine were all off by at least 5-7 when I 1st got mine and tested it against the swing arms.

[NanoReefNovice]

Trust the refractometer.

Floating hydrometers, as well as swing arms can easily be off that much when you test them against a precision instrument like a refractometer. That's on the extreme end but I'd believe it. Mine were all off by at least 5-7 when I 1st got mine and tested it against the swing arms.

 

I know the refrac is percise but w/o calibrating solution Im having trouble believing it is accurate. My hydrometer is a good quality floating one but its not really scaled to the range in looking at, SG of 0.990-1.170, so there goes precision there.

 

The decpreency between my refracs and hydro scares me.

[The Propagator]

I go round and round with people with this same idea all the time.

You don't need calibration solution for your refractometer for our purposes.

There is no salt in RO/DI water so you know your set at zero. I know that's not the entire issue. You want a sample to compare readings from 0-x. But you don't need to if you didnt buy a cheapy to begin with and it has never been abused ( Ie dropped one to many times )

[NanoReefNovice]

I know when i set a refrac to zero that it is accurate at zero, that does not tell me it is accurate at 1.024.

 

One refac i have is a semi cheapo one and the other may have been abused.

 

The refracs are prob the correct ones but its hard for me b/c ive always trusted floating hydrometers over refracs. I guess im going to need proof and get another hydrometer from work.... but that means another day with the salinity out of wack if the refracs are right. CRAP

[Scott Riemer]

Those refractometers aren't for salinity.

 

And for your floating hydrometer:

A deluxe hydrometer for beer or wine with built-in thermometer and correction scale that allows you to instantly correct your hydrometer readings for temperature. A hydrometer reads accurately at 60 Fahrenheit. Temperatures above and below 60F require that you add or subtract from your reading. Like the basic model, the deluxe hydrometer also features three scales - specific gravity, potential alcohol and brix. 12.75" long. Made in USA.

[The Propagator]

No but there is a conversion from brix to sg.

 

http://www.fermsoft.com/gravbrix.php

[Scott Riemer]

And my point is, he set his salinity to 1.024 Brix which is 1.004 specific gravity.

[NanoReefNovice]

Those refractometers aren't for salinity.

 

The only difference in refracs for different industries (testing beer, pee, aquarium water) is the scale. Brix is the same a Platu and there a math converion (about 4X) to get SG. My hydrometer is SG and my refracs are Plato/Brix.

 

And my point is, he set his salinity to 1.024 Brix which is 1.004 specific gravity.

 

No, i set it at 1.025 Specific Gravity or 6.33 Brix or 6.33 Plato

[Scott Riemer]

Then I stand corrected.

 

If you live anywhere near me, You can borrow my refractometer and calibration solution if you'd like.

[NanoReefNovice]

I hate measuring, Im never confident i got it correct and most the time i don't.

 

Then I stand corrected.

 

If you live anywhere near me, You can borrow my refractometer and calibration solution if you'd like.

 

 

Thanks a lot Scott. I can get another hydrometer from work tomorrow, I just dont want the salinity to be 1.013 all day if my current hydrometer if off. I guess its good im cycling but i thought i was more prepared than this.

[evilc66]

Seriously, trust the refractometer. Mineral deposits on the swing arm can bind them up and change the responsiveness of the arm. Plus, like it was mentioned before, you have to compensate for temperature. Even if there is some variance on the refractometer at certain measurement ranges, it's is still going to be more accurate than the hydrometer. +/- 0.002 is a lot better than being 0.010 off.

[Scott Riemer]

evil, he's not using a "swing-arm" hydrometer.

[Mr. Fosi]

Bunch of refracto snobs in here.

[Scott Riemer]

Bunch of refracto snobs in here.

Your point?

 

[Nick's Reef]

The rodi water is fine to calibrate it with. That's what I did with mine since mine didn't come with calibration fluid. I called the LFS to check that it was ok, they said it's fine since their rodi has 0 TDS and I get my ro from them. If the water has 0 TDS then it's pure water correct? Then it should have a salinity of 0ppt. i keep my salinity right at 35ppt or around 1.026.

[Scott Riemer]

Unless...there's distortion in your prism.

[evilc66]

evil, he's not using a "swing-arm" hydrometer.

 

My appologies. Shows me up for not looking at the link that was posted

[The Propagator]

Unless...there's distortion in your prism.

 

That's why I always say the exception is an abused refractometer.

[NanoReefNovice]

Just got back from work and I borrowed a $50+ PRECISION floating hydrometer and it reads my aquarium water is at 1.024 (temperature adjusted 1.023 @ 70F =1.024), just what my other floater says. To remind, my two refracs reed 1.018.

 

In my line of work floating hydrometers are the choice for accuracy, refracs are just for quick checks. The discrepancy of 1.006, and that both refracs read the same is what concerns me. That leads me to think that there in not irregular distortion in the prizm but REGULAR irregular distortion. Refracs don't measure the density of the liquid by buoyancy (a hydrometer) which is much more reliable *not those crap ars swing arm types*. Refracs measure density by how much light a liquid distorts. Some things distort light in an irregular manner, such a alcohol (i know that has no application here). I don't know if something in my aquarium is causing this light distortion discrepancy. But i do know that there are A LOT of nuances to using a refrac correctly, people spend whole semesters on this kind of stuff (def not me).

 

OK... So... To help me solve this i need some calibration solution, which i already ordered and wont come in until the end of the week. B/C of this i decided to try to McGiver some by mixing my Instant Ocean in the ratio specified on the back to get 1.024 and test both refracs and hydro. Will get back soon.

 

Bunch of refracto snobs in here.

 

10-4

 

Unless...there's distortion in your prism.

 

Two different refracts read the same, something in the water distorting light irregularly?

 

That's why I always say the exception is an abused refractometer.

 

Both refracs could not possibly be abused exactly the same (they get the same readings).

[Scott Riemer]

Interested in the results.

[NanoReefNovice]

Interested in the results.

 

water is mixing

 

 

I'm starting to think that this discrepancy between the hydros and refracs is normal in the aquaria world *people who use both please prove me wrong. I guess the most important thing is keeping the salinity consistent.