Houston we have a problem!!

[edulover]

Got my new digital refractometer in yesterday. After zeroing it with RO/DI water, I tested my SG last night and it was 1.029. I can't believe this. I've been using the plastic hydrometer. In fact, I had two of them to compare the two readings. I didn't think they were off that much. I reduced the salinity to 1.027. How fast should I lower the SG to normal? What are the effects of having a high salinity? Are there any long term problems? Other than having a few zoas that closed up, I haven't had any issues at all. Any input would be appreciated.

PS. I want take these plastic things and run over them with my car. Lol...

 

[sharkbait]

Go ahead and throw the plastic hydrometers away. They are practically useless. Secondly I would do small water changes over the next two to three days and lower the salinity back to normal levels. .29 isn't terrible but prolonged exposure to that level you would begin to notice more issues then just your zoas closing up. Remember the key is to not shock the system by rapidly dropping the salinity.

 

[dawgface]

You have calibrated the new refractometer right?

 

[clay4au]

I thought you were suppose to use "distilled" water to calibrate refractometers.

 

[ralph atl]

actually, you should use a known solution of salinity such as this:

http://www.bulkreefsupply.com/catalog/product/view/id/708/">http://www.bulkreefsupply.com/catalog/product/view/id/708/</a>

as the rate of graduation from 0 to 35 is not necessarily the same as 35 to 35.

 

[dr_ fish]

You need to use a calibration solution. Zeroing my refractometer with ro/di or distilled water results in a .002-.003 difference compared to my 35ppt calibration solution.

 

[morganatlanta]

You have to calibrate your plastic hydrometers with a known solution. Get some water with a known 1.025 density (at your LFS), put it in your hydrometer and mark that spot with a sharpie. Once you have 1.025 marked, that's really all you need to know. As long as the needle points at the sharpie line, you are okay. I have one that reads .003 to high (1.028 on the gauge is really 1.025), and one that reads .003 low (1.022 on the gauge is really 1.025).

 

[rdnelson]

mysterybox;860197 wrote: actually, you should use a known solution of salinity such as this:

http://www.bulkreefsupply.com/catalog/product/view/id/708/">http://www.bulkreefsupply.com/catalog/product/view/id/708/</a>

as the rate of graduation from 0 to 35 is not necessarily the same as 35 to 35.[/QUOTE]

+1000000. Calla relate to a level close to what you are wanting to measure.


Sent from my iPhone using Tapatalk

 

[acroholic]

He said he has a "digital" refractometer, which I believe is an electronic unit. Probably a Hanna or a Milwaukee Instruments. It just needs to be zeroed in with either distilled or zero TDS RODI water. You don't calibrate electric units with anything else. The unit shoots a light through the sample and calculates the SG from that. You zero them out with the above before each use (meaning each time you turn the unit on), but can use them with as many different saltwater sources after each zero out.

I have the MI unit, and it is one of the best equipment purchases I have made. Especially handy for multi reef/water change water use. Usually priced online for $100-$110, at least for the MI unit. The Hanna is a bit more. I think the official name is digital seawater refractometer.

 

[ralph atl]

Acroholic;860240 wrote: He said he has a "digital" refractometer, which I believe is an electronic unit. Probably a Hanna or a Milwaukee Instruments. It just needs to be zeroed in with either distilled or zero TDS RODI water. You don't calibrate electric units with anything else. The unit shoots a light through the sample and calculates the SG from that. You zero them out with the above before each use (meaning each time you turn the unit on), but can use them with as many different saltwater sources after each zero out.

I have the MI unit, and it is one of the best equipment purchases I have made. Especially handy for multi reef/water change water use. Usually priced online for $100-$110, at least for the MI unit. The Hanna is a bit more. I think the official name is digital seawater refractometer.

Oops, I missed that! Great catch!

 

[edulover]

Acroholic is right. It is the Milwaukee digital instrument. I've never owned a refractometer and when decided to purchase one I figured I would spend a little extra to get the digital output. Found a great price for new on Amazon. I read the instructions 3 times and I'm sure that I'm operating the equipment properly. Unless it's faulty and it doesn't appear to be. I performed a 1 1/2 gallon water change last night with RO/DI water and it brought the SG down to 1.027. I guess I can do smaller water changes over the next couple of days to get it to 1.025. Is using RO/DI water okay or should I be using salt water with lower salinity? Thanks for the input?

 

[acroholic]

You gotta realize that even these electronic units have a + or - .02 accuracy, but they are consistent at whatever level of accuracy they have. I tested mine against a freshly calibrated ocular refractometer before switching over, and it was spot on, so I haven't worried about it in the 2+ years I have owned and used mine.

If you are ever wanting to know if yours is spot on, take a sample of your water to someone that knows what they are doing with an ocular refractometer and have them compare it to your MI unit.

 

[dawgface]

I regularly sample test against known solution on my Milwaukee. Only once did it mis read and I believe it was my fault in cleaning the lense properly. However even after owning and swearing by them I still checked with regularity, I suppose it had to do with the simplicity of using and checking in and by itself.

 

[edulover]

Okay, so I took a water sample to 3 LFSs today and got 3 different results.

1. 1.026 (hydrometer)
2. 1.029 (refractometer)
3. 1.027 (refractometer)

My test on the same sample was 1.028. So was take the results to mean the digital refractometer to be fairly accurate.