Anyone ever experience unusual salinity spike?

[chowwil]

Hi everyone,
Has anyone ever have unusual salinity spike. I started a 20gal reef tank and couldn’t understand why I keep getting salinity spike. When I do a 20% water change, the night before, I would premix the saltwater that measure 1.26 ( digital refractometer). I test again the premix water, it reads 1.26. So I add to tank. A week later, I notice hammer coral and zoas look funny. Tested the water for salinity. It spiked up to 1.30. Had to add fresh water to dilute water. 2 weeks later I did another 20% water change and did everything the same except, I mixed the salt to read 1.22 the night before. Tank reads 1.26, so added to tank and a week later, it spiked up again to 1.30. This time it killed the hammer. I don’t understand what’s going on. Brand of salt is Fritz.

 

[saltyfilmfolks]

Did you calibrate the refractometer each time ?
And what was the temperature of the water when you mixed it ?

 

[OREGONIC]

Are you dosing? Dosing can increase salinity.

 

[DLHDesign]

The only way that I know of that actually increases salinity is via:
1) A water change where the incoming salt is higher than the existent.
2) Evaporation (generally without an ATO or with one that is not working).

Using a refractometer that isn't calibrated (ideally with a control solution and not just RO/DI water) can certainly report differences in readings from one use to the next.
If you are using a refractometer that does not have any kind of auto temperature correction, then the water you are measuring should be the same temp as the calibration solution used. If your device does have an ATC, then this is something that can take 30-45sec to work; if you read before this you can get false readings.
Another common problem is that the syringe being used to draw water and put it onto the testing surface can get a buildup. It's a good idea to "flush" it a few times (3-4) before drawing a new sample. Also a good idea to draw from as deep as reasonably possible (no need to stick your hand in or anything, but not right at the surface either) - I've found that surface readings can swing more than just a few inches down.

Hopefully something in the above can help. Mostly; I'd suggest calibrating the refractometer several times (2-3 minimum, or until you get a stable reading) using a calibration solution.

 

[chowwil]

Did you calibrate the refractometer each time ?
And what was the temperature of the water when you mixed it ?

Yes, room temp

 

[chowwil]

The only way that I know of that actually increases salinity is via:
1) A water change where the incoming salt is higher than the existent.
2) Evaporation (generally without an ATO or with one that is not working).

Using a refractometer that isn't calibrated (ideally with a control solution and not just RO/DI water) can certainly report differences in readings from one use to the next.
If you are using a refractometer that does not have any kind of auto temperature correction, then the water you are measuring should be the same temp as the calibration solution used. If your device does have an ATC, then this is something that can take 30-45sec to work; if you read before this you can get false readings.
Another common problem is that the syringe being used to draw water and put it onto the testing surface can get a buildup. It's a good idea to "flush" it a few times (3-4) before drawing a new sample. Also a good idea to draw from as deep as reasonably possible (no need to stick your hand in or anything, but not right at the surface either) - I've found that surface readings can swing more than just a few inches down.

Hopefully something in the above can help. Mostly; I'd suggest calibrating the refractometer several times (2-3 minimum, or until you get a stable reading) using a calibration solution.

I didn’t think evaporation can cause salinity spike. I don’t have an ATO. I don’t have this problem with my 75gal. This is my first Nano reef. Didn’t think it will be this much trouble. Thanks

 

[NowGlazeIT]

Remember water perameters swing much faster on Nano tanks. I had an open top bio cube and that thing sucked up 4g of Evap a week

 

[JoshH]

Evaporation can and will raise salinity in a week. Salt doesn't evaporate and stays in the water, the more water that evaporates the less water you have in the tank with the same amount of salt you started with, there for raising your salinity. And as mentioned above, things happened reallll quickly in a nano, only takes 2 gal of evaporation to increase your salinity 10% give or take.

 

[chowwil]

Remember water perameters swing much faster on Nano tanks. I had an open top bio cube and that thing sucked up 4g of Evap a week

Wow, thanks. good to know.

 

[chowwil]

Are you dosing? Dosing can increase salinity.

no dosing

 

[chowwil]

Evaporation can and will raise salinity in a week. Salt doesn't evaporate and stays in the water, the more water that evaporates the less water you have in the tank with the same amount of salt you started with, there for raising your salinity. And as mentioned above, things happened reallll quickly in a nano, only takes 2 gal of evaporation to increase your salinity 10% give or take.

Thanks, good to know. I thought setting up a nano tank would be the same as a large tank. Need to do more research on nano system.

 

[JoshH]

As a whole, they are similar to larger systems, you just need to keep a closer eye on things. If you can pick up an ATO I'd say you're back on track or even figure out how muh evaporation you're having and top up daily to adjust for it.

 

[MnFish1]

it would take a lot of evaporation in a 20gallon tank ie it would be easily noticed to raise the specific gravity from 1.025 to 1.030. Here is a calculator. https://www.hamzasreef.com/Contents/Calculators/TargetSalinity.php

Is there a problem with the measurements? Do your fish etc seen ok?

 

[MnFish1]

The only way that I know of that actually increases salinity is via:
1) A water change where the incoming salt is higher than the existent.
2) Evaporation (generally without an ATO or with one that is not working).

Using a refractometer that isn't calibrated (ideally with a control solution and not just RO/DI water) can certainly report differences in readings from one use to the next.
If you are using a refractometer that does not have any kind of auto temperature correction, then the water you are measuring should be the same temp as the calibration solution used. If your device does have an ATC, then this is something that can take 30-45sec to work; if you read before this you can get false readings.
Another common problem is that the syringe being used to draw water and put it onto the testing surface can get a buildup. It's a good idea to "flush" it a few times (3-4) before drawing a new sample. Also a good idea to draw from as deep as reasonably possible (no need to stick your hand in or anything, but not right at the surface either) - I've found that surface readings can swing more than just a few inches down.

Hopefully something in the above can help. Mostly; I'd suggest calibrating the refractometer several times (2-3 minimum, or until you get a stable reading) using a calibration solution.

Or replacing evaporated water with salt water

 

[chowwil]

it would take a lot of evaporation in a 20gallon tank ie it would be easily noticed to raise the specific gravity from 1.025 to 1.030. Here is a calculator. https://www.hamzasreef.com/Contents/Calculators/TargetSalinity.php

Is there a problem with the measurements? Do your fish etc seen ok?

Fish are fine. Thanks

 

[chowwil]

Or replacing evaporated water with salt water

dang, you just solved my problem. I’ve been replacing evaporated water with saltwater. I don’t have this problem with my 75gal. Usually when my sump in 75 is getting low, it’s already time for water change.