Salinity
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Rmckoy
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Hanna tester. Easy to use and accurate
JumboShrimp
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I have the one from Icecap. For what I have— a FOWLR tank, and a smaller tank with soft corals— I think it’s fine. I think since it first came out the price has dropped from around $99 to around $69. I love it, actually, and bought a second one (still new in the box) in case the first one ever goes ‘kaput’.
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I prefer conductivity to measure salinity, but refractometers and hydrometers all can work.
I'm not sure what you mean by a "digital hydrometer". Actual digital hydrometers are extremely uncommon in the hobby (I've never, ever seen someone report using one). Perhaps that is a mislabel of a digital conductivity meter or digital refractometer.
Whatever you use, be sure to check its accuracy with an appropriate test fluid.
I'm not sure what you mean by a "digital hydrometer". Actual digital hydrometers are extremely uncommon in the hobby (I've never, ever seen someone report using one). Perhaps that is a mislabel of a digital conductivity meter or digital refractometer.
Whatever you use, be sure to check its accuracy with an appropriate test fluid.
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Rmckoy
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The picture i attached in a reply is labeled as a digital hydrometer .
I have always used a refractometer but looking for input if to upgrade or stay with what I know works
wes urquhart
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+1 , this is my primary tool.Hanna tester. Easy to use and accurate
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Then it's a marketing gimmick. It is not a digital hydrometer. It is a conductivity meter.
A hydrometer by definition measures density or specific gravity (same thing, different units).
This is a digital hydrometer:
SBS-2510: Digital Hydrometer and Tester
Digital Specific Gravity Tester with Downloading Capabilities The SBS-2510 is ergonomically designed and lightweight, allowing one-handed operation. An easy-to-use joystick offers intuitive operation with guided workflow. A built-in motor and automatic sampling pump draw electrolyte into the...
www.sbsbattery.com
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Rmckoy
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1 other addition to this question ...Then it's a marketing gimmick. It is not a digital hydrometer. It is a conductivity meter.
A hydrometer by definition measures density or specific gravity (same thing, different units).
This is a digital hydrometer:
SBS-2510: Digital Hydrometer and Tester
Digital Specific Gravity Tester with Downloading Capabilities The SBS-2510 is ergonomically designed and lightweight, allowing one-handed operation. An easy-to-use joystick offers intuitive operation with guided workflow. A built-in motor and automatic sampling pump draw electrolyte into the...
If for some reason as I experienced a few days ago .
stray voltage from a old pump was removed as soon as I found it .
Does that effect the conductivity to be inaccurate ?
JoshO
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Sorry to hijack the thread, but do you have a link to your recipe for test fluid @Randy Holmes-Farley ?
Miller535
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I would say yes.
Miller535
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Why do you prefer this Randy? Not arguing, just curious.
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It shouldn't, but I cannot be sure with a cheap device. Generally, it is a high frequency oscillating current between 2 or 4 electrodes, so normal electrical voltages should not interfere.
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They all can work fine.
But conductivity is easy to check with DIY or standard commercial solutions (and not hobby company solutions, but true big company products like from Oakton, Fisher, Cole-Parmer, etc.) , is very quick, and can read continuously in situations such as acclimating, where, at least some, continuously read salinity and temp during, say, drip acclimation or during making a new batch of salt.
Depending on the device, it can also serve other purposes, such as determining the potency of kalkwasser/limewater (you know how much to add/when you can stop mixing, etc.). That cannot be done with a refractometer or a hydrometer (at least not the same ones used for seawater salinity).
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Here's a little blurb from a very old article of mine that describes how they actually work:
Can I just drop some electrodes into the water and measure the resistance with a meter? No. Several factors make that impossible. The size and shape of the electrodes are significant, but more important is what happens at those electrodes. If you apply a DC current to seawater, numerous reactions take place when the ions hit the electrodes. Some ions will plate out on the electrodes, some may bubble off as gasses, and the electrodes themselves may dissolve. These and other effects all serve to change the nature of the solution at the electrode, impacting the measured conductivity.
So how do conductivity probes get around this problem? They, in fact, use an AC current rather than DC. Using fields that oscillate, there is no overall movement of ions toward one electrode or the other. The ions move one way for a tiny fraction of a second, and then back the other direction for the second half of the cycle. Overall, the solution and electrodes stay unchanged and the conductivity is accurately measured. Modern conductivity meters use complex AC waveforms to minimize additional complications such as capacitance, which can interfere with simple conductivity measurements.
In practice, commercial conductivity probes have either two or four electrodes, with the four-electrode version being more resistant to fouling and other effects that can cause degradation of the measurement. The electrodes are made of nonreactive materials such as epoxy/graphite, glass/platinum or stainless steel. The choice depends primarily on the nature of the solution to be tested. For occasional use in seawater, all of these are acceptable.
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Can I just drop some electrodes into the water and measure the resistance with a meter? No. Several factors make that impossible. The size and shape of the electrodes are significant, but more important is what happens at those electrodes. If you apply a DC current to seawater, numerous reactions take place when the ions hit the electrodes. Some ions will plate out on the electrodes, some may bubble off as gasses, and the electrodes themselves may dissolve. These and other effects all serve to change the nature of the solution at the electrode, impacting the measured conductivity.
So how do conductivity probes get around this problem? They, in fact, use an AC current rather than DC. Using fields that oscillate, there is no overall movement of ions toward one electrode or the other. The ions move one way for a tiny fraction of a second, and then back the other direction for the second half of the cycle. Overall, the solution and electrodes stay unchanged and the conductivity is accurately measured. Modern conductivity meters use complex AC waveforms to minimize additional complications such as capacitance, which can interfere with simple conductivity measurements.
In practice, commercial conductivity probes have either two or four electrodes, with the four-electrode version being more resistant to fouling and other effects that can cause degradation of the measurement. The electrodes are made of nonreactive materials such as epoxy/graphite, glass/platinum or stainless steel. The choice depends primarily on the nature of the solution to be tested. For occasional use in seawater, all of these are acceptable.
Miller535
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Do you have a particular brand or model you use/like?
JoshO
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Is the iodized salt replaceable with table salt?
