Salinity probes...what's the story here? Why aren't they reliable?

[Ntvper]

When it is something out of your control, then it's a matter of trust. So much of reefing is.

Do you trust that manufacturer "A" put the right chemicals in its salt/additive/etc. Checking is way to expensive.

Do you trust that even the standard you are using is accurate? Depends on the company, IMO. Hobby companies are always suspect until they somehow demonstrate and earn our confidence. Big science supply and food supply companies are much less suspect.

A bottle of Morton's food grade sodium chloride or Mrs Wages pickling lime or an Oakton conductivity standard or 0.1 N HCl from Fisher Scientific is highly unlikely to be substantially off, but is every ingredient in a commercial two part or salt mix actually added correctly?

Too error is human but to really screw things up takes a machine

 

[BrianNRoe]

They all suck and I finally went old school and got a hydrometer that floats. This helps me compensate for the crappy meters, because I have a known baseline to work from.

I second that. n nothing beats my floating hydrometer

 

[Randy Holmes-Farley]

I second that. n nothing beats my floating hydrometer

It has become very chic for folks to make such a claim, but, IMO, a good quality conductivity meter is far more useful, and most users of hydrometers or refractometers haven't actually used a good quality conductivity meter.

They read salinity and temp in real time in a reef tank, an acclimation bag, or other settings where a large hydrometer is inconvenient, and a hydrometer cannot read other properties, such as limewater/kalkwasser potency or tap water/RO/DI TDS.

 

[ConnivingPigeon]

Is the big issue a film accumulating on the probe? What if you remove it from the water between measurements? (Possibly with a dip in R/O)

 

[Randy Holmes-Farley]

Is the big issue a film accumulating on the probe? What if you remove it from the water between measurements? (Possibly with a dip in R/O)

I don’t know if that is the critical factor, but I think it is a good practice to keep it clean. I never left mine in the water and it always worked perfectly.

 

[vetteguy53081]

I don’t know if that is the critical factor, but I think it is a good practice to keep it clean. I never left mine in the water and it always worked perfectly.

I too rinse after use and dry it with canned air after each use

 

[1112-425XL]

It has become very chic for folks to make such a claim, but, IMO, a good quality conductivity meter is far more useful, and most users of hydrometers or refractometers haven't actually used a good quality conductivity meter.

They read salinity and temp in real time in a reef tank, an acclimation bag, or other settings where a large hydrometer is inconvenient, and a hydrometer cannot read other properties, such as limewater/kalkwasser potency or tap water/RO/DI TDS.

What is the price point of what you refer to as a good quality conductivity meter?

 

[Pod_01]

haven't actually used a good quality conductivity meter.

Randy what is considered good quality conductivity meter?
I use GHL and honestly it is good to see trend but I don’t trust it.
I used Red Sea Refractometer and that seem to have produced random results (probably my own fault).
The TM floating hydrometer works well but you are correct it is cumbersome to use.
I would love to find easy to use device that I could quickly measure new salt mix, tank etc… and if it doesn’t break a bank account that be bonus.

 

[Randy Holmes-Farley]

The best conductivity meters use 4 electrodes and are not pen types. I use a no-longer-sold Orion model 128, which some reefers have gotten off ebay.

Even used they are not cheap. I think reefers may even be a part of the reason used ones are not cheap.

 

[KStatefan]

The best conductivity meters use 4 electrodes and are not pen types. I use a no-longer-sold Orion model 128, which some reefers have gotten off ebay.

Even used they are not cheap. I think reefers may even be a part of the reason used ones are not cheap.

Is there a model that is availble new that you recommend?

 

[attica38]

I have the same Hanna salinity tester and hate it. I mostly go by my apex probe and it is generally reliable for me, but every once in a while I will get a crazy reading. I’ve always heard it was because of air bubbles but I don’t actually know that to be true.

My APEX Probe is usually pretty good but same as you, sometimes I get these off the chart readings. This morning it happened to me just out of the blue spiked to 53.8 for no reason. checked it with my other reading and was 33