seachem doesn't give the ingredients for prime so there is a bit of conjecture on fish keeping websites/forums, the majority of water dechlorinators use sodium thiosulphate or similar to remove chorine and convert excess chloromines to ammonia (this is why doing a water test after doing a water change can give erroneous results).
although it is difficult to overdose dechlorinators they do use the oxygen in the water to work so making sure that there is a means to oxygenate the aquarium is essential.
seachem stability is aerobic bacteria in a bottle to help start a filter and for general maintenance (always a good idea to dose a couple of hours after a water change in case any filter bacteria is harmed because of chlorine remnants), there are numerous products on the market that do the same job although it can be cheaper to get pond bacteria as it tends to be cheaper size for size.
