He was already a manufacturer, having earlier developed ammonia-free hair color after he discovered he was allergic to that chemical.
当时他已经是个制造商了，生产不含氨水的染发剂，这是他发现自己对氨水过敏后开发的。
2
The experimental results showed that the nitrite accumulation obtained from selective inhibition of high concentration freeammonia to nitrifier was unstable.
试验结果表明：通过高浓度游离氨对硝化菌选择性抑制所获得的亚硝酸盐积累是不稳定的；
3
This ammonia becomes toxic to your fish so you need to provide them with a healthy clean environment and ammoniafree water which has been filtered properly.