Replacing Evaporated water in a Reef Tank

[podo98]

Obviously every few days I have to add water to replace evaporated water in my 75 g tank. The guy at the fish store said to just add filtered drinking water. Is that good advice and if so how "filtered".

[reefrunner69]

If you have a reef system, then you should use RO or RO/DI water for your waterchanges and for top off. The reason is that RO/DI water is about as pure a water as you can get, anything less and you are adding impurities to the tank that will fuel algae and possibly harm your inverts. Remember, when you are replacing evaporated water...the only thing that left the tank was pure water, so that is what you need to replace, FW only for top off.

[maiceman]

This is where a dosing pump really comes in handy. At around 300 mg/hr I pretty much keep up with evaporation. So I find I need to fill a 5 gallon water jug once every 5-6 days. This keeps me from having more dramatic shifts in specific gravity and salinity as well.