Time to Deep Six the Deep Six

[RonD]

Just FYI but thought it is worth mentioning

I just purchased a Refractometer to check our Salinity levels properly. I have been using the Coralife Deep Six swing meter and a glass floating one as well... they both read exactly the same. I checked the calibration in the new meter and set out testing our QT and our display tank. The Refractometer showed the water in our tank to be 1.027. The Deep Six showed 1.023. that is a huge difference.. glad our tank wasn't really cranked up to 1.027 on the Deep Six or we would have been having really big problems and looking else where for the reasons why.

 

[Randall_James]

Yes the lesson of the Refractometer is a good one. It is worth mentioning as well, using both on occasion is a good idea as well.

I calibrate my Refractometer every week with RO/DI as the zero setting. It does seem to wander about .01 a week for some reason and I suspect it is the $69 issue over the $129 one

 

[angelsj247]

accually when you use a hydrometer the salinity depends on the temperature..(i dont think alot of people know that).. and heres a calculator to show.. so depending on your temp- your hydrometer was probably pretty accurate.
I keep my salinity on my hydrometer to 1.023 and a temp at 79 degrees which accually means the salinity is 1.025

Heres a link that does the convertion:
http://www.efishtank.com/WetNet/Misc/SaltCalc.asp?Temp=0.00226|79&Measured=1.023

 

[poppin_fresh]

My Deep Six had my tank @ 1.030 and it read 1.024! That was right after a vinegar soak too.

I've decided to put it to another use as a target for my .357 magnum. It should be interesting to watch it be obliterated.

 

[Scuba_Dave]

Swing arm...back...throw...it out

 

[RonD]

<a href=showthread.php?s=&postid=7284487#post7284487 target=_blank>Originally posted</a> by angelsj247
accually when you use a hydrometer the salinity depends on the temperature..(i dont think alot of people know that).. and heres a calculator to show.. so depending on your temp- your hydrometer was probably pretty accurate.
I keep my salinity on my hydrometer to 1.023 and a temp at 79 degrees which accually means the salinity is 1.025

Heres a link that does the convertion:
http://www.efishtank.com/WetNet/Misc/SaltCalc.asp?Temp=0.00226|79&Measured=1.023

Interesting .. I just did a test using both again at 80 degrees and my deep six was still off by 0.0035 (bold numbers) using that conversion calc. against the refractometer

 

[sassyfishy]

I had a similar experience with my Deep Six. It consistently measured S.G. at 1.024. When I bought my refractometer, it measured 1.028.

 

[rivank]

Here's Something funny..... Took a water sample in yesterday to LFS to test for the nitrates and they tested salinity for me as well and had no clue that a swing arm is dependent on temp as well. Water had cooled and their test said I was low on salinity. Hey would temp effect a nitrate reading as well?

 

[kau_cinta_ku]

temp won't change nitrate readings.

 

[Randall_James]

<a href=showthread.php?s=&postid=7284487#post7284487 target=_blank>Originally posted</a> by angelsj247
accually when you use a hydrometer the salinity depends on the temperature..(i dont think alot of people know that).. and heres a calculator to show.. so depending on your temp- your hydrometer was probably pretty accurate.
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Actually I think most people are aware of this, I do not however think that most are calibrated at 60 degrees. I have checked dozens of swingarm style hydrometers and the vast majority are off by +/- .015 and not - .015 If they had been calibrated at the 60 degree mark they would all be on the - side.

Lab grade floating hydrometers are a different story completely from the hobbyist swing arms.

Best rule of thumb, if you can not afford a Refractometer, check your clean, bubble free reading against a good refractometer and find the deviation for your particular unit.

Just adding the .02 or so of that chart could be a disaster for some tanks

 

[Amphiprion]

Just in case, you also may want to check any salinity (or specific gravity) reading device against a known standard that matches seawater. I believe randy has some good articles to do this in the chemistry forum. This should allow for a reasonable degree of precision as well as peace of mind (since you don't know how the manufacturer set the equipment).