High salinity

[CristianD]

So after 3 years in the hobby I finally smartened up and bought a refractometer. I calibrated it using ro/di water (0 tds) and even tested tap water which was only slightly higher than the ro water. I tested my tank water and surprise surprise my sg was really high (1.030/40 ppm). Obviously my 3 year old refractometer was way off (1.025 sg).

So I know that's a huge mistake on my part not recalibrating my refractometer or waiting this long to buy a refractometer but you live and you learn I guess. The reason I never really thought much about it is that everything I my tank seems to be ok. My fish are healthy, my anemone is always open (over a foot in diameter) and my sps are growing. The only sps that don't seem to be doing that great are a strawberry shortcake and blue echinata frags. My calc has been a little high lately ~500. My alk around 10 and mag about 1400. Phos and nit almost 0. Can a high salinity affect corals? Also what's a good time period to lower my sg? Is a week to short?

Thanks for the help!

 

[thirty5]

First, I would not use RO to calibrate the unit. Get calibration fluid. You can get it on ebay for pretty cheap. That is the only way that you will be sure that you are calibrated correctly... So I would not rely on your readings unless properly calibrated.

 

[duke62]

thats not true thirty.some use calibration fluid while others are desined t be calibrated with distilled water.i personally would use distilled water over ro/di.if it is 1.030 i would lower the salinity slowly over a month to 1.025

 

[thirty5]

I stand corrected, everything i have read said not to use RO, and to use calibration fluid..

 

[Aquarium Village]

So after 3 years in the hobby I finally smartened up and bought a refractometer. I calibrated it using ro/di water (0 tds) and even tested tap water which was only slightly higher than the ro water. I tested my tank water and surprise surprise my sg was really high (1.030/40 ppm). Obviously my 3 year old refractometer was way off (1.025 sg).

So I know that's a huge mistake on my part not recalibrating my refractometer or waiting this long to buy a refractometer but you live and you learn I guess. The reason I never really thought much about it is that everything I my tank seems to be ok. My fish are healthy, my anemone is always open (over a foot in diameter) and my sps are growing. The only sps that don't seem to be doing that great are a strawberry shortcake and blue echinata frags. My calc has been a little high lately ~500. My alk around 10 and mag about 1400. Phos and nit almost 0. Can a high salinity affect corals? Also what's a good time period to lower my sg? Is a week to short?

Thanks for the help!

Hi

I have found that fish and corals that are already established in the system make be able to take the high salinity that sometimes occurs. Remember the increase in the salinity happens over a period of time. When you add a new fish or coral they may not react as favorably and usually that is when the the high salinity is found while checking your parameters. Since everything looks pretty good I would lower the salt slowly. Nothing stresses the animals more then abrupt changes to the stability of the tank

Good Luck

 

[duke62]

if you google "refractometer calibration" you will come across 100 people that say use calibration fluid and 100 people that say use distilled water..the instructions on my refract says to use distilled water while another members refract says t use the fluid.ive been usin distilled water and everythin seems fine in my tank.my only concern when usin my refract was light source i used to check.i now only calibrate my refract in natural sunlight.

 

[CristianD]

Thanks for the imput. I'll try and get a calibrating fluid and see if calibration is different. Either way I think my sg reading is still gonna be pretty high so I'll try and lower it slowly.

 

[Boomer]

I guess you guys missed this post a few day ago.

And Duke you have read it was yours. Duke quite feeding people BS on my forum.


Duke & others

ALWAYS calibrate with my REFRACTOMETER with distilled water first then check my main tanks salinity


That is a no-no, as said refract can be just as for off as a swing-arm hydrometer. Cheap Chinese refracts have been shown to be off from 0 -5 ppt when calibrated in RO/DI water. To many in this hobby are being fooled that a refract is accurate. It is only accurate if it is a real seawater refract when calibrated in RO/DI water. Any refract should be calibrated using PinPoint 53 mS calibration solution or similar. You just put a drop or so on the refract and cal to read 1.0264, or 35 ppt or 3.5 % depending on what scale it has. A real lab grade refract at tune of $250 will be off in seawater @ about - 1.5 ppt. Almost all refract are for salt water, as in table salt water and NOT seawater. All of those ions in seawater, like Ca++, Mg++ SO4, K+ etc. change the RI (Refractive Index) of the water being tested. There are lost of places to buy this PinPoint from, here is on example.

The Filter Guys
http://thefilterguys.biz/refractometers.htm

As pointed out Swing-Arms can be off too and usually it is from poor care. They need to be rinsed after each use in RO/DI water and placed in a zip lock bag. If left wet, after use in seawater, the salt will precip onto the plastic needle weighing it down giving false low reading when in actuality the salinity is high.


and

It is std practice for std refract, like most used in this hobby, where it is calibrated from the factory using NaCl. A refract based on pure water, NaCl water, KCl water, sugar, etc., DO NOT refract the light the same. Therefore, a refract has to bet set to the solution you are testing. Most refracts are used for saline or Brix solutions, which seawater is not.

Digital Hand-held "Pocket" Refractometers Scales
http://www.atago.net/english/images/.../hand-held.pdf

Refractive index

http://en.wikipedia.org/wiki/Refractive_index




I spent allot of time for Randy Holmes-Farley to help him on this article. Feel free to go ask him, he is on RC.

Refractometers and Salinity Measurement

http://reefkeeping.com/issues/2006-12/rhf/index.php



one says to calibrate with distilled water

But the scale on the refracts are NOT the same. The scale for NaCl is not the same for seawater any more than the scale is the same for sugar. RO/DI is just used more or less to zero it out and put it back on track if its off.

 

[duke62]

Boomer how am i feedin people BS on your forum?should i copy my instructions from my refractometer?i can do the same for my friends refractometer.i answered a post a few weeks ago on what you told me about the refracts that measure salinity but table salt not seawater and i got jumped on for what you told me..where is this coming from.i took wha you told me seriously and started lookin into buying a seawater refract.i dont understand your logic for jumpin on me

 

[Boomer]

I do not care what your instruction say they are for a table salt refract. I explained this to you in detail and here you are still trying to argue, convey to use DS water. If you took what I said serious why did you not post a link to that discussion we had instead of this this gibberish ?

if you google "refractometer calibration" you will come across 100 people that say use calibration fluid and 100 people that say use distilled water..the instructions on my refract says to use distilled water while another members refract says t use the fluid.ive been usin distilled water and everythin seems fine in my tank

You are STILL asserting the claim to use DS water, after I told you clearly NOT to.

 

[duke62]

here is my instruction to my refractometer.i will listen to MY instructions because my tank is doing well.if i use the fluid and its way off will you be paying for my livestock?this is what its says to do and this is what im doing.been doing it for 2 years and everything is doing great.i called marine depot and they told me NOT to use the calibration fluid on this refractometer
http://c2.f3images.com/IMD/UserManuals/MD2101 .pdf

 

[Boomer]

I do not care what your instructions say or some lost person form MD says. If you want to follow their gibberish nonsense have at it. I dare that so called person from MD to come here for a debate. Wont' happen will it You appear lost and beyond any help on this issue on understanding basic facts. You are one of those guys that is flat wrong and afraid to admit it, so you continue to care on the old remarks, to hope I will go away. WON'T HAPPEN.

if i use the fluid and its way off will you be paying for my livestock?

This is so silly it is not even worthy of a comment.

 

[allenjj]

Which is Better?

I read the articles you cited Boomer and now wondering how the electronic digital refractometers made for seawater stack up in your opinion? Can you also elaborate on why the Vee Gee refractometer is your recommendation? Am trying to learn and decide as I upgrade to a new one. My apex system has the ability to add a probe for conductivity, but not sure which would be consistently more accurate.

 

[Boomer]

The Vee-Gee Allen is a Seawater refractometer and NOT a table salt refract. There are only 3 real hand-held refracts set to seawater, the Vee-Gee, Vital Sine (same exact one as the Vee-Gee only sold under that name by Foster & Smith) and a almost ~$300 ATAGO lab grade. So, in short, there is only one in the world for us, the Vee-Gee/Vital-Sine. This is its data sheet.

http://veegee.thomasnet.com/item/sa...salinity-scale-optical-refractometer/43036-2?

Take note of the "Accuracy" @ +/- 1 ppt. You do not get much better than that unless you spend hundreds of dollars and that is for any instrument measuring Salinity.

Vee-Gee also has a Digital that has no better Accuracy THAN ^ and it costs $275

http://veegee.thomasnet.com/item/sa...tal-refractometers-cdx-series-models-3/44236?


There are cheaper Digitals, like the Hanna for ~ $100 -$200 and the Milwaukee is a Hanna re-labeled. And their Accuracy is +/- 2 ppt.

Accuracy what does it really mean ? It means if you test your tank and it says 35 ppt, that means the salinity is guaranteed to be somewhere between 33 - 37 ppt. Just because it reads 36.6 does not mean anything. Any refract no matter what kind, type or price should always be tested against a calibration solution and I do not mean DW or RO/DI water either. That is what is done in the real world of science and testing for ANY instrument.

conductivity

This is the international std for testing seawater Salinty in chemical oceanography/marine chemistry. This is fine to use do but some probes are really touchy and piss people off. Meaning, just changing the water current, moving the probe a few inches, can change the number/salinity reading. People need to learn that such sensitive instruments need time to "settle-in" to get a proper reading. Your issue is how much is that probe and or any additional software.

Personnel I think the Vee-Gee/Vital-Sine is a steal at ~$100. Many of these, unlike all others, have been calibrated in DW and tested with a cal std and are always right on the nose @ 35 ppt. These are also FULL range seawater refracts. When you take these NaCl refracts and use them in seawater they are only good for a narrow range. Does this mean mean that one of these cheap crappy Chinese refracts can not be right on like a Vee-Gee in DW and a cal std. Yes, we have shown that it too can be right on. Why/ How ? Due to their crappy optics you just lucked out and got one. But some of these have been off as much as 4 ppt. Any quality grade refract will read 1.5 ppt to low in seawater that is know to be 35 ppt. Why ? Because it is suppose to read 1.5 ppt low, as it is not a seawater refract but a table salt, NaCl refract. And many, even respectable refract companies, mislead the public some times not knowing and some times knowing that are not for seawater. Salinity does not always mean seawater salinity. There is Seawater Salinity and NaCl Salinity and many refract companies treat them as if they are the same, be it hand-held or digital and they are not the same.

 

[allenjj]

Thanks

Thanks so much. That was really helpful as I am ordering the VeeGee now. I am probably going to invest in the conductivity probe as well and use the vee gee for double checks. Its always great to have someone so knowledgeable to ask. Am ordering the calibration solution as well.

 

[Paolissimo]

conductivity[/B]

This is the international std for testing seawater Salinty in chemical oceanography/marine chemistry. This is fine to use do but some probes are really touchy and piss people off. Meaning, just changing the water current, moving the probe a few inches, can change the number/salinity reading. People need to learn that such sensitive instruments need time to "settle-in" to get a proper reading. Your issue is how much is that probe and or any additional software.

Personnel I think the Vee-Gee/Vital-Sine is a steal at ~$100. Many of these, unlike all others, have been calibrated in DW and tested with a cal std and are always right on the nose @ 35 ppt. These are also FULL range seawater refracts. When you take these NaCl refracts and use them in seawater they are only good for a narrow range. Does this mean mean that one of these cheap crappy Chinese refracts can not be right on like a Vee-Gee in DW and a cal std. Yes, we have shown that it too can be right on. Why/ How ? Due to their crappy optics you just lucked out and got one. But some of these have been off as much as 4 ppt. Any quality grade refract will read 1.5 ppt to low in seawater that is know to be 35 ppt. Why ? Because it is suppose to read 1.5 ppt low, as it is not a seawater refract but a table salt, NaCl refract. And many, even respectable refract companies, mislead the public some times not knowing and some times knowing that are not for seawater. Salinity does not always mean seawater salinity. There is Seawater Salinity and NaCl Salinity and many refract companies treat them as if they are the same, be it hand-held or digital and they are not the same.

Boomer where do you stand on salinity probes for controllers? Would you rather spent $107.95 for a VeeGee refractometer or buy a salinity probe for a controller? Are salinity probes that are calibrated with a Pinpoint or similar fluid as accurate as a VeeGee refractometer for salt water salinity?
Thanks for your explanation.
By the way I calibrate my refractometer with Pinpoint solution, when I used RO/DI, RO/DI was usually one to two point higher then the pinpoint solution, and I think my ro/di water is pretty good, i have a spectrapure unit.
Again thank you.

 

[Boomer]

Boomer where do you stand on salinity probes for controllers?

A Salinity probe is a conductivity probe. They are often referred to as Salinity probes when the controller, no the probe expresses Salinity only in ppt, like the PinPoint Salinity Monitor. Expensive conductivity meters /probes often have both. Conductivity is measured in Siemens and coverting Siemens to Salinity in ppt is just like converting temp in C to F. 53 mS = 35 ppt = 1.0264 Sg @ 25 C. At the top of my forum here is a link to many calculators to include to do these conversions of Salinity, from on unit to another, as many get lost with Siemens as the are not use to it and many even with ppt, as they only look at Salinity in Sg (Specific gravity)

Would you rather spent $107.95 for a VeeGee refractometer or buy a salinity probe for a controller? Are salinity probes that are calibrated with a Pinpoint or similar fluid as accurate as a VeeGee refractometer for salt water salinity?

1. A Conductivity/Salinity probe/meter will always be more accurate / say, as there is more user error involve when dealing with looking in a refract window and where that line sits.

2. The units in Conductivity/Salinity probe are smaller, as often it is 35 ppt vs 53 mS and expensive Cond. units can be more accurate with even smaller units like 53,065 uS.

3. If on wants to monitor the Salinity 24/7 then a Cond or if one has issues with window viewing a refract. But Cond. are electronic devices an can go bad and damaged more easily.

4. A meter can be put where you can always view it. So, if there is any issue with a shift in Salinity you can see it now. Case in point: If the ATO goes bad and it is in area like back room or basement and you do go there ever day or a few times a day you may miss the "accident'. A 24/7 meter will catch it if it is right next to the tank where yo can see it. These events have happened to may reefers, i.e., they saved their tank or it crashed. If not 24/7 I will go with a refract, they are close enough and I do not have to worry much if it gets dropped in the water or on the floor.




By the way I calibrate my refractometer with Pinpoint solution, when I used RO/DI, RO/DI was usually one to two point higher then the pinpoint solution

It should be that, as a NaCl refract cal in RO/DI water needs to read 36.5 ppt to = 35 ppt Seawater.

 

[allenjj]

Boomer was Right!!!

Just thought I would close the loop on Boomer's recommendation of the Vee Gee refractometer. Have had it now since a week after my question to you. WOW!!!!! What a well made piece of equipment. Your can feel the difference it is construction just picking it up. Viewing the reading is so clear and easy I now understand why you recommended it. Thanks for your help and advice.

 

[Boomer]

That is what all say when they get one

 

[tomtoothdoc]

hi boomer,

you had mentioned that there are only three sea water refractometers available to us. what about the DD H2Ocean natural sea water refractometer? i picked one up a while ago at one of the past MR swaps. the instruction recommends "pure or ro water" to "zero" the calibration process. it also states that the calibration temp. of the refractometer is 20*C/68*F.

http://www.theaquariumsolution.com/files/SEAWATER REFRACTOMETER V2.pdf

i used the pinpoint calibration fluid of 53.0mS @77*F/25*C to set the refractometer to 35 ppt, which the corresponding s.g. is 1.0265(1.0266 according to the chart on page 2 of the refractometer instruction but i'm unable to discern the 0.0001). when i check with the ro/di, the line is now above "zero".... so far so good. i would rather not use the ro/di and calibrate with the pinpoint solution instead.

the esv salt mix instruction indicates that their 34 ppt is 1.0256 @77*F, should that still read 34 ppt on the refractometer if the fresh saltwater is 79*F?
i have a spare chinese refractometer that i also calibrated at 35 ppt using the pinpoint solution. should i calibrate that to 36.5? what should the 34ppt fresh salt water read on it if it were calibrated to 36.5?

i also have a pinpoint salinity monitor that i calibrated to the solution at 53mS....but the conversion chart indicates that at 53mS and 35 ppt, the sg is 1.0259. the chart doesn't indicate where those numbers correspond to in term of the temperature (calibration temp nor sample temp).

right now my tank reads ~36.5 ppt or ~1.0275 on the DD refractometer but the pinpoint monitor reads between 53.5-54.0 mS which is 35.40-35.7 ppt or 1.0262-1.0265 in s.g., the tank temp is ~79.5*F

would you please help me make some sense out of these numbers. btw the system is a 300 gal. sps dominated mixed reef.

thank you in advance.