Salinity Issue

[A Toadstool Leather]

I topped off my tank too early causing my salinity to get too low. It is at 30ppt and I measured it with an refractrometer that was calibrated before use. How bad will this be for my corals and fish. What can I do to slowly correct this error aside from letting the water evaporate?

 

[Katrina71]

I recently had the opposite issue. Looking forward to the educated response on this. I was also curious if the ocean experiences fluctuation in salinity.

 

[Randy Holmes-Farley Verified Community Expert]

If the water level is normal, I'd top off with 35 ppt seawater until the salinity rises to where you want it.

if the water level is very high due to excess top off water, I'd just let it drop by evaporation back to normal levels.

You can accelerate these processes a bit with fans to increase evaporation, but you don't want to go too fast.

 

[A Toadstool Leather]

If the water level is normal, I'd top off with 35 ppt seawater until the salinity rises to where you want it.

if the water level is very high due to excess top off water, I'd just let it drop by evaporation back to normal levels.

You can accelerate these processes a bit with fans to increase evaporation, but you don't want to go too fast.

I have some 35 ppt seawater. I might do that once some water evaporates. How long will it take for enough water to evaporate? My tank is 30 gallons.

 

[Randy Holmes-Farley Verified Community Expert]

I have some 35 ppt seawater. I might do that once some water evaporates. How long will it take for enough water to evaporate? My tank is 30 gallons.

Depends on evaporation. Most people evaporate 1-4% daily.

At 2% daily, the salinity will go as:

salinity by day
30
30.6
31.2
31.9
32.5
33.2
33.9
34.6
35.3