Salinity Increased Mysteriously

[ItsAName]

So I was curing my rocks and had the salinity perfect at 1.026. Well the tank ended up taking longer to set up than expected (you know, life happens!) and my rocks cured for about 2 months. 4 times during that two months I added RODI only because water was evaporating. I checked the salinity today, the first time in 6 weeks and it's 1.032 How could it increase especially since I only added RODI and no additional salt?

 

[clowner]

what was the water volume?
and did u have a set waterline?

also temperature has a big impact on salinity

 

[ItsAName]

Its very possible the temperature was different but I don't think it was. I did not have a set waterline, but I filled it up approximately to the same point each time. There was probably about 35 gallons of water and each time I refilled it, I added about 3-5 gallons.

 

[morpheas]

How are you measuring salinity?

 

[redfishbluefish]

Its very possible the temperature was different but I don't think it was. I did not have a set waterline, but I filled it up approximately to the same point each time. There was probably about 35 gallons of water and each time I refilled it, I added about 3-5 gallons.

You answered your own question........1.032 is approximately 1.026!

But the big issue is that you only topped off approximately every 2 1/2 weeks with 3 to 5 gallons....that salinity swing seems pretty big.

 

[Salty1962]

When you setup your DT, you'll want to look into purchasing an ATO to keep this from affecting your DT