It is because Aquasafe neutralizes heavy metals and Prime does not that I created this thread. On the other hand, Prime works against ammonia and Aquasafe does not. I was wondering if the two can be used in concert in a large aquarium? Maybe do half the water change with Prime and the other half with Aquasafe. Will this work or will it hurt the fish?tdkee1;4827411; said:aquasafe says it neutralizes heavy metals also. i dont think prime does. not a big deal for me. Ill still always use prime.