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View Full Version : just a reminder, check your refractometers


sjfishguy
03/13/2008, 02:11 PM
Starting the end of Jan, I started to notice that my tenius was getting burnt tips. Nothing really changed in my tank, didn't really know why. Then I started to lose color on some other corals, couldn't figure it out. My superman bleached out. Did some water changes with 1.025 salinity water, and things didnt improve. My tank was at 1.025, as it always is. Then I added a new skunk cleaner shrimp and it was dead when I woke up the next day. I wrote it off as another shrimp killing it. Then I was acclimating a new acro and thought I would check my salinity, 1.025. And then I thought to myself, I haven't calibrated my refractometer in a while. So I got the calibration fluid out and WOAH was it off. I was running my tank at 1.021 for who knows how long! So over the course of a few days I raised it back up to 1.025.

The tenius has almost totally healed up, colors are starting to look great again, and things are really looking good again. Its been two weeks since the problem and things look drastically better. Funny thing is I didn't lose a single coral and things still looked pretty colorful, just not as good as they usually did. So for all of you that are having problems with burnt tips and loss of color, etc. maybe its as simple as checking your refractomer. I know I will be calibrating mine monthly from now on just to be safe.

Waxxiemann
03/13/2008, 02:17 PM
where do you get calibration solution? Can't you just use Ro/DI?

leeweber85
03/13/2008, 02:18 PM
I'm surprised that little of a change in salinity would cause that much damage.

sjfishguy
03/13/2008, 02:30 PM
No, RO/DI does not work. The refractometers we use are too cheap. You need to calibrate using a solution close to the salinity you are trying to acheive. The solution below should be used to calibrate to 35ppt. Randy Holmes-Farley has a technical article about it if you are interested, but trust me, you can't just use RO/DI like the instructions for the refractometer may say.

http://www.marinedepot.com/ps_ViewItem~idproduct~AM1437.html

Waxxiemann
03/13/2008, 02:32 PM
gracias

alve
03/13/2008, 02:55 PM
I used to calibrate mine with distilled water. Last week I received the calibration fluid sjfishguy mentioned above from Marine Depot.
I always thought I had my SG at 1.025, after calibrating it showed my actual SG was 1.021-1.022.
I have been bringing it up slowly with just topping off with NSW.
Definitely shows that you should use calibration fluid instead of RO or distilled water.

unbreakable
03/13/2008, 03:49 PM
mine wasnt horribly off. i had used ro/di water to calibrate, then i bought the fluid a week ago and it wasnt that huge of a difference. instead of the 35ppt it was actually at 36ppt. i had the cheap 40 dollar refractometer too

j.prostrata
03/13/2008, 03:53 PM
Very nice reference solution here also.

http://www.reefperfection.com/index....ROD&ProdID=469

mr. pluto
03/13/2008, 04:15 PM
wow! thanks for the info, something to to look closly at.