Salinity way off (maybe) help please!

[maleks.reef]

I measured my salinity today using my red sea refractometer (i calibrate with rodi) and it says 1.025. then I measured with the tool that looks like a thermometer and floats in the water, it gave me 1.028.. could my salinity be this high all along which is why my softies are very slow growers and my lps have died? Keep in mind, the floating salinity checker is like 5 years old.. what do i do?

 

[atul176]

I measured my salinity today using my red sea refractometer (i calibrate with rodi) and it says 1.025. then I measured with the tool that looks like a thermometer and floats in the water, it gave me 1.028.. could my salinity be this high all along which is why my softies are very slow growers and my lps have died? Keep in mind, the floating salinity checker is like 5 years old.. what do i do?

order 35 parts per thousand calibration fluid instead of RODI. It's more accurate assuming that your currently calibrating with not salty RODI water. If you can't do that rn, ask your local fish store if they can test for you.

 

[kaylajoy]

I second the calibration fluid.

All my instruments read slightly different as well and it seems to be a common problem.

 

[T_BONE]

The refractometer should be checked with some calibration liquid to ensure it is measuring correctly. BRS has some that I use to calibrate mine to 35ppt. I don’t trust those float type because if there is the slightest little bubble on the needle it will give false readings. Just my $.02. Hope this helps.

 

[mikereefing]

Try making your own calibration solution using Randy's recipe here. I have three different brands of calibration solution and they ALL measure differently despite claiming 35ppt. If you have an accurate and sensitive scale, I would go this route. I had a super low salinity previously because of the inconsistencies among brands and within the same brand itself..

 

[ZoWhat]

I measured my salinity today using my red sea refractometer (i calibrate with rodi)

Calibrating a refractometer with RODI to 0 is like calibrating a car's speedometer to 0 why its parked

Calibrating it to 0 doesn't give it any data to compare to.....just an indication there's no data. Any data thereafter is almost a guarantee the results will be way off.



.

 

[Gtinnel]

I agree with making your own reference solution to test your refractometer. It measured exactly 35ppt for me after I had bought 35ppt solution that wasn't 35ppt. If you calibrated the optical refractometer with rodi then I would guess that the floating hydrometer (not a swing arm style) is probably the more accurate test. I don't believe age makes any difference to the floating hydrometer.

 

[maleks.reef]

Assuming my refractometer is not accurate and i am indeed 1.003 SG off, would this explain the very slow growth of the softies and the death of my euphillia?
(By slow i mean my tiny gsp frag grew an inch at the very best in the last 3 months)

 

[Gtinnel]

Assuming my refractometer is not accurate and i am indeed 1.003 SG off, would this explain the very slow growth of the softies and the death of my euphillia?
(By slow i mean my tiny gsp frag grew an inch at the very best in the last 3 months)

I doubt it. Although a little higher than most of us keep our tanks it's not ridiculously high.

EDIT- Many people aim for 35ppt, which is 1.0264, which means your only .0016 over.

 

[PeterB113]

+1 calibration fluid

 

[Philly Reefer]

After having many questions about my own tank Salinity, I bought a Tropic Marin High Precision Hydrometer.
Then I calibrated my refractometer, Apex Salinity probe, and hanna Salinity from there...