Topping off the tank...

[Brian Bivens]

I have a question...

While I was setting up my tank I accidentally mixed the salinity too high. Since I have uncured live rock only in my tank, I just pulled out 5 gallons, and replaced it with 5 gallons of freshwater....

In a normal circumstance, when adding more water to a tank, and with evaporation, Can you just top off a saltwater tank with freshwater? What about when fish are present in the tank, would the water being introduced hurt them?

I am a newb, so this may spawn more questions for me... Thanks in advance...

 

[snappyguy]

Top-off water should be freshwater as the salt does not evaporate from the tank. Adding saltwater will increase your salinity.

 

[Conski]

Yea man i do about a gallon top off everyday in my 14 gal with fresh RO water.. the salinity will stay constant because salt does not evaporate with the water

 

[Brian Bivens]

So adding freshwater doesn't hurt the fish?

What about doing a water change, how do you maintain the same salt levels? Wouldn't it be slightly off each time if you follow the directions?

 

[Blown 346]

So adding freshwater doesn't hurt the fish?

What about doing a water change, how do you maintain the same salt levels? Wouldn't it be slightly off each time if you follow the directions?

With water chnages say you take out 10 gallons. Make your new saltwater. As long as the salinity in the new water is the same as the tank the salinity in the tank wont change. Just make sure the salinity is at the level you want in the new water and you will be ok. You have to make sure you put in the same amout of water you took out.

 

[fsn77]

Yes, definitely top-off with freshwater (hopefully RO/DI).

There can certainly be some variability in the SpG of the saltwater when it's mixed. If you're not doing so already, it's a good idea to actually measure the SpG after it has had some time to mix and adjust it as needed to match the level you're aiming for in your tank.