Learn How to Use Refractometers and Hydrometers in an Aquarium

In an aquarium, hydrometers and refractometers are needed to keep an eye on the pH of the water, which is very important for the health of marine life. In this case, here’s a full guide on how to use each tool:

Using a Hydrometer in an Aquarium

Most of the time, hydrometers are used in tanks to find out how salty the water is by measuring its specific gravity (SG).

Set the hydrometer’s readings:

• Make sure that your hydrometer is clean and doesn’t have any dust on it.
• Most hydrometers are already adjusted, but it’s still a good idea to compare them to a known standard or calibration solution if you have one.

Get a sample of the water:

• You can either put the hydrometer right into the aquarium or take a sample from the tank using a clean container.
• If you are using a jar, make sure to rinse it with tank water before you take the sample.

Get the hydrometer full:

• The tank water should be put into the hydrometer’s chamber. For swing-arm hydrometers, make sure the arm is floating easily and doesn’t have any bubbles connected to it.

Read this:

• Lay the hydrometer down on a flat surface and wait for the number to stay the same.
• Find out the specific gravity of the water at the top. A pointer on a swing-arm hydrometer will show the SG.

Write down the temperature:

• Write down how hot or cold the water sample is. Some hydrometers have thermostats built right in.
• If you need to, use temperature correction charts to change the SG number because it can change with the weather.

Using a Refractometer in a Fish Tank

The refractive index of the water can be found with a refractometer, which gives a more accurate reading of salt.

Set up the refractive spectrometer:

• Clean the prism with water that has been distilled, and let it dry 100%.
• On the prism, put a drop of purified water or a calibration solution. Then, close the cover plate and look through the lens.
• The calibration screw should be turned until the line between the light and dark fields reads 0 on the salt scale (for pure water) or the known value of the calibration solution.
• Before you use the prism, clean and dry it again.

Get a sample of the water:

• Grab a clean dropper or pipette and take a look at the tank water.

Put the sample on the prism:

• A few drops of the sample should be put on the prism of the refractometer. Make sure that the water sample covers the prism all the way around.
• Close the cover plate to get rid of any air bubbles and spread the liquid out evenly.

Read this:

• Point the lens at a light source. A line will show you where the light and dark fields meet.
• The salinity reading is at the place where this line passes the scale. This is usually given in parts per thousand (ppt) or specific gravity (SG).

Write down the temperature:

• Take note of how hot or cold the sample is. A lot of refractometers are Automatic Temperature Compensating (ATC), which means they can handle changes in temperature without any problems. If your refractometer doesn’t have ATC, you can use an adjustment chart to change the number based on the temperature of the sample.

How to Get Accurate Measurements

• Clean the tools: Make sure that both the hydrometer and the refractometer are clean before you use them to keep them from getting dirty and to get accurate numbers.

• Avoid Air Bubbles: When using a hydrometer, make sure that the swing arm or floating device doesn’t have any air bubbles connected to it. If there are, the number will be wrong.

• Consistent Methodology: To get accurate numbers every time, always use the same method to collect and measure samples.

• Regular Calibration: To keep your refractometer accurate, you should adjust it regularly with clear water or a known calibration solution.

If you follow these steps, you’ll be able to correctly check the salinity of your tank and keep your marine life healthy.