topping off with fresh water? good idea? bad?

[Nate Peters]

Hi, i use hang on equipment to filter and skim so the water frequently needs to be topped off, so the units get suction. this can change my salinity, Since i have my cuttle eggs, can i continue just dumping fresh water in when it calls for it or do i have to do something else? cuttles are sensitive to water chemistry changes, so thats why im asking.

 

[Kerrick]

Might I suggest an ATO...

 

[Jean]

I would NOT use freshwater! Make up (or get) seawater. Cephs are not very tolerant of salinity changes. Also if you have copper pipes you will kill them. Can you get RO water from your supplier and use something like red sea salt (you'll need to measure salinity!) to make up a batch of salt water, you can make it in bulk and keep it in covered buckets with an aerator in it.

 

[DWhatley]

Jean,
I believe he is referring to top off of evaporated water, not water changes. In a home tank, we don't have a flow through system like the aquarium and we have to compensate for evaporation with freshwater or the tanks would become as salty as the dead sea.