After following the instructions exactly on Red Sea Coral Pro salt, salinity is VERY low

[mike550]

yes and no, it’s calibrated at 25c so the water needs to be 25c when you take the reading, my tank is 26c so time I pour 500mls into measuring cylinder it’s 25c, you can use a chart to get a reading if say the water was only 20c, you can also just measure it straight from the tank but the flow needs to be off to read it, you can also easily break the hydrometer in the tank on a rock etc but for all that the reading it gives is extremely accurate and it never needs calibrating, good to know your salinity is correct.

Ah ... I was thinking more towards the OP question of mixing new saltwater.

 

[Reef.]

Ah ... I was thinking more towards the OP question of mixing new saltwater.

same applies, either use a correction chart or heat 500ml of fresh mix to check, as said it’s not so much a salinity checker to use every day but worth it to have one for a reference.

 

[Rubberfrog]

I'm using the scale to measure how many grams of salt I need for 35 gallons of water. Volume wise, it ended up being 1/2 cup per gallon of water.

How much can volume change due to moisture?

Voume won't change, density will. That is why you can not weigh the salt.

 

[Adamantium]

Doesn't a hydrometer require temperature correction or you need to measure at the temp the hydrometer is calibrated?

It does. Here's a great calculator for it.

Salinity Correction Calculator

Aquarium calculator; Correct a relative specific gravity (sg) measurement taken with a non-temperature-correcting unit.

www.hamzasreef.com

 

[Adamantium]

Just a word of warning, I actually have both a Hanna Salinity Tester and a Tropic Marin Hydrometer. Thanks to the hydrometer, I discovered that my Hanna tester was reading low. What it said was 35 PPT was actually more like 38-39. Even with calibration. I still use it, but now I just know to mix my water to more like 32PPT, and it comes out to 1.0264 on my hydrometer.

 

[golgobot]

Just a word of warning, I actually have both a Hanna Salinity Tester and a Tropic Marin Hydrometer. Thanks to the hydrometer, I discovered that my Hanna tester was reading low. What it said was 35 PPT was actually more like 38-39. Even with calibration. I still use it, but now I just know to mix my water to more like 32PPT, and it comes out to 1.0264 on my hydrometer.

How do you get 4 decimal places of precision? That blue line is pretty blurry. I certainly can't tell the difference between 1.025 and 1.0251. Usually I round to the nearest thousandth. Am I missing something?

 

[Adamantium]

How do you get 4 decimal places of precision? That blue line is pretty blurry. I certainly can't tell the difference between 1.025 and 1.0251. Usually I round to the nearest thousandth. Am I missing something?

It’s really easy with the Tropic Marin High Precision Hydrometer.

 

[Reef.]

How do you get 4 decimal places of precision? That blue line is pretty blurry. I certainly can't tell the difference between 1.025 and 1.0251. Usually I round to the nearest thousandth. Am I missing something?

very easy, this is my hydrometer, as you can see the water lvl is at 1.0291, I was mixing a fresh batch of salt.