Salinity?

[tmccaffery]

I calibrated my Apex Salinity probe and my tank reading 31.9ppt which is 1.024sg. My hydrometer reading at 1.024. I think reading where curvuture stops (One that floats); Seems the Milwaukee way off wow. Milwaukee reading at 35ppt 1.027sg

Which to trust? I read Milwaukee and says can be 2 degrees off in either direction.

 

[mcgyvr]

None can be 100% trusted really but if your probe was really calibrated and who knows on the rest then I'd go with that provided I trusted my ability to calibrate it properly...(I might even try to calibrate it again and see how that goes...
But they are totally close enough so any of them are fine IMO..

 

[tmccaffery]

Neptune calibrated probe for me. Should I adjust my tank to 35ppt using Apex probe? I made new water should I test that?Would test alk and calcium give me a better idea of salinity in new water?

 

[mcgyvr]

You said "I calibrated" then "Neptune calibrated".. which one is it?
Do you have the calibration solutions?


Pick on that you will use and set the tank to that..

 

[lapin]

I use 2 different refractometers. Calibrated the first of each month. They seem to be very good at holding the salinity. Rarely do I need to adjust them. My probes on the other hand seem to need adjusting more often. Maybe its buildup of some sort. Maybe you can compare readings with a calibrated refractometer. Just food for thought.

 

[tmccaffery]

Neptune just calibrated it

 

[tmccaffery]

Hmm? I went to this link:

https://www.hamzasreef.com/Contents/Calculators/DirectSaltCalculator.php

Water Volume 2050ml
Current salinity 0
Target Salinity 35ppt
Temp 70
Water Impurity in Salt Mix: 4.93 (Using Red Sea Coral Pro)
Added 75ml around

Apex Probe Reads 35.4 dead on almost
Milwaukee Reads 46ppt ??
Hydrometer reads 1.026

I calibrated Milwaukee using supplied distilled water and zero it and reads 1.000sg

So I am guessing need to use Apex for water changes and or get another refractometer. I cant believe the Milwaukee is off this much

 

[top shelf]

When it comes to testing it's nice to have backups to double check but it can also cause a lot of confusion and panick. Someone says I checked x with x test then checked x again with x test and it's giving me this reading which do I go by. If everything looks good and happy pick the one you have the most confidence in and go with it. Hobby grade anything has a certain percentage it can be off so most likely you will always get different results. Stability is more important then numbers within reason.

 

[m14socom]

You could take a water sample to a Pool store. They usually test it for free. Most of them use a $3500 tester that is fairly accurate.

 

[thegrun]

I would check it against a calibrated refractometer. I really don't trust a conductivity probe to give anything other than a ballpark number, they are very prone to false readings from electrical interference and the temperature compensations are less than perfect.