Is the paint, right when u stuck them In the water air got trapped under the paint making blisters on the orderments, u can keep orderments in high ammonia nitrates etc and nothing will happen it was petsmart bad painting!
I was actually going to say the white stains are caused by hard water. 8.0 PH is semi hard.. But I don't have any issues with the paint on my ornaments and my PH is 7.5.. The only issue I had with paint was the paint peeling off over time. Those ornaments look like they are using a type of glossy paint. Glossy paint can bubble like that... its the same as if you paint your wall in the house and pour water on it if it gets under it it will bubble... The normal Ornaments like the volcano's and coral looking stuff those use a better type of dry paint.