Topping off the aquarium fresh water?

[Kingumar]

Hey, I am almost a newbie in this business.. i just read somewhere today that water top offs should be done with freshwater not saltwater.
Well... i didnt know this

Heres the explanation i read:

"Did You Know?

Did you know that one of the most common mistakes made by the novice marine aquarist is topping off their aquarium from evaporation with salt water? You must top off your aquarium with FRESH water. The salt does not evaporate so as the water level decreases (from evaporation) the salt level increases. You would only use salt water if you are trying to slowly raise your salinity or if you are performing a water change. So the lesson is: top off with fresh to maintain a stable salinity and water change with salt. And don't forget to use your hydrometer or refractometer regularly to be sure your salinity is stable and consistent. "

so i should change my ways huh ?

[fox2589]

im guilty of topping off with saltwater for the first 3 -4 months in this hobby..HA i thought someone was messing with me when they told me..amazingly my clowns and shrimp and starfish seemed just fine and i never lost anything until about a year in when i "knew what i was doing" lol..-drew

[Kingumar]

haha oh wow, so its true! im an idiot..
hhahaha

[Hop]

Then the second most common mistake surfaces... Not topping off with RO/DI water

[Kingumar]

i have been using 99cent distld water from my local store..
no big problems yet!

[Hop]

Distilled is fine

The term "fresh water" always seems to mean tap water to me...

[ibanez2k]

Yep, as Hop said, it is very important to top off with fresh RO/DI water. If RO/DI water is unable to be obtained, distilled water works well too and can be purchased in gallon jugs from most supermarkets for usually under a dollar. The reason for RO/DI water or distilled water is that all the other minerals in your water, like the salt content, do not evaporate either. Good RO/DI water and distilled water contains 0 TDS so by using it you will never have to worry about adding any minerals or chemicals to your water that could become a problem. It will save you many possible headaches in the future.

[Jnicho]

Not to mention the phosphates most municipalities add to tap water to combat pipe corrosion!

My own little anecdote about topoff...my very first tank (over 20 years ago) was a local species tank from Long Island Sound...I had no way to even test for SG...every week I went down to the beach park and filled up some gallon jugs for water changes/top-offs...after months and months of this I can't even imagine how high the salinity must have been!

[Loverotties]

They both are close to be either 1 or 2.