All My Problems Solved! ?

[ouling]

Got a new pointy salt meter today. It is from "deep 6" made by coralife. It is brand new and advertise to me that it is already calibrated on the little pointer thing. I did a test with my 2 older pointy meters and it said my SG is 1.021; "Deep Six" said it's at 1.021. Who should I believe? I am go take it to Cap Bay and have them use the spec meter to test it. I can't get my hands on one till monday.

Maybe this is why my tank is being strange lately... hummmmmmmm

 

[jgoal55]

if you can...I would seriously consider buying a refractometer.......a million times more accurate and well worth the cash....this one works great and is relatively inexpensive....and you'll never have to worry if your reading are off....

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=9957&Ntt=refractometer&Ntk=All&Ntx=mode+matchallpartial&Np=1&pc=1&N=0&Nty=1">http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=9957&Ntt=refractometer&Ntk=All&Ntx=mode+matchallpartial&Np=1&pc=1&N=0&Nty=1</a>

good luck.

 

[ouling]

Type, the 2 old meter said it is at 1.026, new one said it's at 1.021.

And yes, i already ordered one of those thingy.

 

[jgoal55]

yeah i figured it was a typo but it doesnt really change the point that they are just all pretty inaccurate....good that you ordered a refractometer already...you'll see what a difference it makes when you compare it to the hydrometers

 

[ouling]

Hydrometers are absolutely POS... But I believe the new one is more accurate and precise. Man... I used that hydrometer for someone else too... need to go to his house and pour some salt into his tank. JEEP9783 I hope you're reading this post!!!!!!

 

[xyzpdq0121]

A difference of 1.021 or 1.026 is not enough to be the cause of all your problems...

Now I would bet you $10 that both of those hydrometers are wrong though!

 

[cameron]

You can buy Pinpoint Salinity calibration fluid. It is what I use on my refractometer to dial it in. It is a calibrated salinity close to where you measure so it is far more accurate than using RO/DI or Distilled.

 

[jmaneyapanda]

Cameron;54550 wrote: You can buy Pinpoint Salinity calibration fluid. It is what I use on my refractometer to dial it in. It is a calibrated salinity close to where you measure so it is far more accurate than using RO/DI or Distilled.

I read somewhere the device used to determine the salinity of those fluid is a refractometer that is calibrated from distilled. Which came first, the chicken or the egg?

 

[cameron]

I talked to the pinpoint guy about a variety of things and this was one. He told me the reference fluid is calibrated lab grade and is used by various high end systems to calibrate their systems. Either way, start with distilled water dial in your refractometer and see if you read the same as the pinpoint bottle. I am willing to bet you are dead on if they line up.

 

[jmaneyapanda]

Cameron;54565 wrote: I talked to the pinpoint guy about a variety of things and this was one. He told me the reference fluid is calibrated lab grade and is used by various high end systems to calibrate their systems. Either way, start with distilled water dial in your refractometer and see if you read the same as the pinpoint bottle. I am willing to bet you are dead on if they line up.

Oh yeah, Im sure the stuff is accurate, that wasn't what I was trying to state. I am just curious as to whether this calibration fluid is "better" than using TDS 0 water. To be honest, the discrepancy, if any, would likely be so negligible in terms of our purposes for reefs, right?

 

[cameron]

Not necessarily. Lets say your meter is off 0.005. That would mean you could easily be enough out of scew to be causing real problems in a tank if you calibrated at 0. If you know a mixture is 1.026, you are calibrating so close to your target that you simply can't be that far off unless the calibration fluid is off. The closer to your target you adjust the less variance you will have in your measurements. Seriously, how many reliable meters do you know that are only tested against one source? It is just safer to calibrate on two ends. One end is 0 for distilled or RO/DI water and the other is the Pinpoint calibration fluid. You are virtually guaranteed a good reading if both those check out. Calibrating at only zero means your meter isn't off when it reads zero water and is probably closer to reading 1.025 correctly just better hope the meter guages were measured correctly and printed on the unit properly.

 

[jmaneyapanda]

Cameron;54634 wrote: Not necessarily. Lets say your meter is off 0.005. That would mean you could easily be enough out of scew to be causing real problems in a tank if you calibrated at 0. If you know a mixture is 1.026, you are calibrating so close to your target that you simply can't be that far off unless the calibration fluid is off. The closer to your target you adjust the less variance you will have in your measurements. Seriously, how many reliable meters do you know that are only tested against one source? It is just safer to calibrate on two ends. One end is 0 for distilled or RO/DI water and the other is the Pinpoint calibration fluid. You are virtually guaranteed a good reading if both those check out. Calibrating at only zero means your meter isn't off when it reads zero water and is probably closer to reading 1.025 correctly just better hope the meter guages were measured correctly and printed on the unit properly.

Yeah, but I'm not sure I follow. You are correct, when you calibrate close to target, the degree of error is certainly less than calibration way off target, but with refractometers, there is only one adjustment. It is not like a pH meter or similar that has two calibration functions (zero and slope). For example, what if you set it to zero with distilled, and then put 1.035 and it reads 1.036? What do you do? Turn it down? Then the zero set is off. I dont understand how double calibrating will help you with this piece of equipment.

Nonetheless, I understand what you are saying. If I had my druthers, claibration solution would be the way to go. But, here is my point- lets say I dont use calibration solution, and I use distilled. And lets say, using your example, it is 0.005 off. How much does that translate or shift once you get up to 1.025? My speculation is not that much. I am guessing only slightly more than 0.005. I dont know this for a fact, just guessing. But ebven so, with my hydrometer, I can only differentiate, AT BEST, to 0.5 or so- my eye cant tell the difference between 1.025 and 1.0245. So for my purposes, unless it calibrated distilled water to be 0.1 off or more (which is very unlikely, I'm sure you will agree), I can't see that one will FUNCTIONALLY wotk better for me, than the other. TECHNICALLY, absolutely, but I can't see functionally.

 

[cameron]

You are trusting that the printing and measuring of the lines were correct on the refractometer. I am sure with some of the high end versions out there, it isn't an issue but the mass produced chinese knock offs likely don't have a lot of checks and controls in the manufactoring process. This is the same with a probe. You are aligning the meter with the probe. At the very least you will know if one of your source measurements are off (such as contaminated distilled water). Once it is dialed in and tested out, you are correct frequent checks on both ends isn't a big deal but for a few bucks you can make absolutely sure your number and meter is right the first time.

As for being .005 off, I know a lot of people that don't sit right on 1.026. They often run high or low. If you are at 1.020 which is low but workable throwing inverts in 1.015 might be a problem.

 

[cameron]

BTW, before this fluid I did calibrate mine inline with a hyrometer. I knew two instruments wouldn't be as likely to lie to me. It is just safer to make sure your instruments are at least reasonably accurate.

 

[jmaneyapanda]

Cameron;54644 wrote: You are trusting that the printing and measuring of the lines were correct on the refractometer. I am sure with some of the high end versions out there, it isn't an issue but the mass produced chinese knock offs likely don't have a lot of checks and controls in the manufactoring process. This is the same with a probe. You are aligning the meter with the probe. At the very least you will know if one of your source measurements are off (such as contaminated distilled water). Once it is dialed in and tested out, you are correct frequent checks on both ends isn't a big deal but for a few bucks you can make absolutely sure your number and meter is right the first time.

As for being .005 off, I know a lot of people that don't sit right on 1.026. They often run high or low. If you are at 1.020 which is low but workable throwing inverts in 1.015 might be a problem.

I see your point. This becomes an issue when the variation of accuracy between 1.000 and 1.026 is skewed excessively, the further we get from 1.000. Well, yeah, crap is crap, and if you buy a crappy refractometer, you take your chances- just like all the other equipment in this hobby. So I will agree with your moral of this story- if you own a P.O.S. refractometer, calibrate with solution.

I still dont understand how double calibrating can help any hand held refractometer, though. Aside from making you feel good if it's spot on. At any rate, even a crappy refractometer will likely be better than a hydrometer. Everyone should own one.

 

[roundman]

I work with Hospital instruments in the lab and IMHO if the issue is to verify that the markings are correct then you should cal with 0 and then run the standard as a control to assure that there is not a problem with the light or anything else with your meter. Then run your tank sample. That would be the correct way to run this test with a piece of equipment. Once you do this you can then check your markings for accuracy and adjust them as necessary.
Good Luck

 

[ouling]

Wow there is alot of post. I tested it with lab equiptment and it is at 1.026 exactly. I guess my old ones are right after all.