Sponge not doing well...with picture

[Rippin]

Hi all,

I've searched the site and found some info on sponges but I thought I'd post a new thread and list my specific circumstances.

I bought a blue sponge on Saturday and today (Monday) it's turning white!!

1. I did not expose it to air - neither did the fish store.
2. It's in a med-high flow area with a lot of light.
3. The area that is turning white is the frontal area exposed to the water flow.
4. I did a water change and added reef buffer and calcium yesterday - could that have affected it?
5. When I did put the sponge in (with other new corals) my protein skimmer went a bit crazy and was putting a lot of micro bubbles in the water. Could that have done it?
6. Is there any way to recover this sponge? Will it ever get it's colour back?
7. How far should I let it go before it is considered unsafe to leave in the tank?

Any help would be appreciated. Thanks.

Obligatory picture: