zennzzo;2329089; said:
OK here is another thought...
If I added more than the recommended amount of de-chlorinator, will there still be some unused in the tank? And how long will it be available for de-chlorinating?
Tough to give an honest answer on this one.
Sulphates can be consummed over time as an energy source (reducing agent) by anaerobic bateria that lurk in the dark recesses of a mature tank. Live rock, deep substrate etc that aren't turned over frequently will harbour these bugs. As they consume sulphate they produce sulphide which you can detect as that rotten egg smell.
This is not a bad thing however as these same bugs will consume nitrate and nitrite reducing these anions to oxygen and nitrogen gas.
There is little danger of overdosing with thiosulphate based dechlorinators within reason. As far as the other ingredients in prime and stresscoat, I suspect they are just buffers and fillers, and beyond the fact that your thickening the soup of chemicals in your tank, I don't see any serious threat-accept to your pocket book.
There are much cheaper sources of thiosulphate, including the old darkroom chemical 'Fixer' if you can still find it anywhere. It seems it getting more difficult to buy straight chemicals these days...