Casper

Hi quick question, can I refill my tank with bottled mineral water instead of tap water. Good idea, Bad idea? when performing 30 to 40% water change.

COBettaCouple

Welcome to Fishlore.

I like to use treated tap water, but we do have members who use bottled water, but I'm not sure if they use mineral water or not.

Blub

Aquarium-Enthusiat

Hi,

Bottled water may be fine. But... what kind of bottled water?

Mineral water has, well, minerals in it. If there are too many minerals in your water, your aquarium water will be very hard and the pH may rise to undesirable levels.

Of course, if you have fish (such as African Cichlids, or even Mollies) that like hard water, mineral water should not be an issue. Most other fish, however, like a neutral or soft water. For these fish, adding mineral water may be problamatic...

A good alternative to bottled mineral water is bottled RO (reverse osmosis) water. As this Aquarium Care article on tap and RO water explains, RO water is pure H20 (yay!).

That gives you a blank-slate to work with. You can add trace element supplement solutions to RO water to get it to the hardness and pH that's perfect for your fish!

Also, since RO water is pure H20, it has no chlorine, phosphate, heavy metals, nitrates, or any of the other nasty stuff that water treatment companies add to our drinking water, you don't need to treat it.

So, I think RO water is a much better alternative to any other types of bottled water. You can find RO water at most grocery stores, at some LFS, and you can even make it yourself!