Starting over! Just siphoned the last of the "toxic soup" and plan to add spring water. I live in the country and there is a natural spring near here with crystal clear water. It is the best water you ever tasted...very clean, no taste or smell. It is a lower ph than my tap water. Has anyone ever added spring water? Is there any reason it would not be good in the tank?
Also wish to raise some rock in my tank and wondering if there are any rules about plastics? Would, say, a throw away plastic butter bowl cause any problems? Thanks!
Also wish to raise some rock in my tank and wondering if there are any rules about plastics? Would, say, a throw away plastic butter bowl cause any problems? Thanks!

Any food safe plastic should be safe for use with fish so long as it is cleaned thoroughly first, be careful how you position it to avoid dead spots in the water, and to avoid fish getting trapped.