extra foam from skimmer when adding water to tank

B wrote:
Hello.

I am very new with marine tanks. I have a Coralife protein skimmer
that tends to overflow whenever I add new water to the tank (to replace
evaporated water). I am using tap water, with a standard water
conditioner.

The extra foam ceases after a day or so, but until then, I have to turn
the water level down very low on the skimmer to avoid overflow. Even
at lowest levels, there is lots of foam that goes over-the-top, and I
have to keep emptying the canister.

Is this a result of using tap water? water conditioner?, or just
expected behaviour?

thanks,
B.

Water conditioners very commonly cause these problems.

Kim