Refractometer vs. Deap Six swing arm hydrometer
Printed From: Utah Reefs
Category: Specialized Discussion
Forum Name: Equipment
Forum Description: This is the place to ask question about reef equipment.
URL: http://www.utahreefs.com/forum/forum_posts.asp?TID=44329
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Topic: Refractometer vs. Deap Six swing arm hydrometer
Posted By: ninja_brandon
Subject: Refractometer vs. Deap Six swing arm hydrometer
Date Posted: October 29 2010 at 12:35pm
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Im sure most everyone who has been in the hobby for a long time has invested in a refractometer eventually to get an accurate reading on their salinity. I have been in the hobby for 1.5 years now and have always used my original deep six hydrometer. I was aware that they were inaccurate so I decided to take mine to Fish 4 U to have them calibrate it using a refractometer. Essentially I would take what the value that is displayed and add.02 to the result. Yesterday I bought my first refractometer from bulkreefsupply.com for $35. I tested my water's salinity with both instruments and found that even with my calibrated hydrometer I was off .04 I wanted to post this topic in case someone was searching the boards for information on refractometers. Even though I was a skeptic at first, I am now on board with owning a refractometer. Depending on what you run your salinity at, this could potentially problems given hydrometers don't always provide an accurate reading. Also over time the hydrometer gets old and if you are as lazy as I was, you never wash the hydrometer out with clean water. This could potentially cause problems down the line for you and your tank.
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Replies:
Posted By: TriggerHappy
Date Posted: October 29 2010 at 12:58pm
 You are now enlightened grasshopper.
------------- 210 gallon Mixed Reef |
Posted By: Lewy
Date Posted: October 29 2010 at 2:03pm
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you never wash yours? If I don't my arm sticks to the sides and I don't get any type of reading, good or bad. You did bring up something I do need to do and check my calibration. ------------- 40 gal w/ 20 sump |
Posted By: Will Spencer
Date Posted: October 29 2010 at 2:23pm
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I had 2 deep 6 hydrometers for a while and they tested the same water different by .06 degrees. If not cleaned regularly salt deposits can build up on the swing arm and cause readings to be off. Those deposits will not dissolve when the water is tested again a week or two later. If left long enough I suppose they might, but typically we draw water and take a reading rather than drawing water, waiting 30 minutes and then taking the reading. When my mom got her first tank it came with an old swing arm hydrometer. Thinking it would of course work properly we used it to test the salinity. Corals lived in the tank very well, but fish just kept dying. After several weeks she got a refractometer and tested the salinity to find that it was 1.35, way too high. We fixed the problem and the next few fish lived a long happy life. I went 10 years before getting a refractometer for myself and only got it recently because my cousin was selling it. |
Posted By: Shane H
Date Posted: October 29 2010 at 2:27pm
I just add salt to taste. 
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Posted By: Mark Peterson
Date Posted: October 29 2010 at 7:18pm
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Shane has done this long enough. I believe him. Seriously. Of course anything from 1.020 - 1.028 is within the totally acceptable range. We should not get too worked up about salinity. From my experience, there is no perfect. I often taste the salinity of the water that comes with a fish or coral. That tells me whether I have a 10 minute or a 20 minute acclimation period.  After calibrating a Hydrometer just once by comparing it to a true correct value, if it's kept clean by rinsing in freshwater after each use and a vinegar bath every 3 months or so, it will be accurate for the rest of your life. BTW, You can make your own calibration salt solution and calibrate anything by that, refractometers included. ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member 
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Posted By: swiftra
Date Posted: October 31 2010 at 11:36am
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I'll bite Mark. How do you make your own calibration salt solution?
------------- If you make it idiot proof, someone will find a better idiot! Well 100g crashed when I moved it. Starting a 50g cube now. |
Posted By: Mark Peterson
Date Posted: October 31 2010 at 10:28pm
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6.20 grams of sodium chloride, and 161.00 grams of RO/DI water = 1.028 specific gravity OR Salt mix containers [used to] say what salinity the resulting mix will be if salt to water proportions are used exactly as instructed. The one I just looked at says 1/2 cup to one gallon should be used but still should be checked with a meter. I find it interesting that this salt company recommends fish are best kept at 1.021-23 and coral at 1.021-24. I would assume that their 1/2 cup/gallon of water puts the sg within that range. Some of us old timers mix up salt water in that way and only rarely bother checking it. A little variation is no big deal. ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member
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Posted By: Lewy
Date Posted: November 01 2010 at 1:14pm
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so you're saying we should follow instructions? ------------- 40 gal w/ 20 sump |
Posted By: swiftra
Date Posted: November 01 2010 at 4:23pm
Lewy instructions are for sissy's!  Mark there is no way this lazy reefer could get anything that exact. But still good info to know. File that one away in the might be useful one day section of the brain.
------------- If you make it idiot proof, someone will find a better idiot! Well 100g crashed when I moved it. Starting a 50g cube now. |