yes, I saw that it is uncycled. That's an unfortunate circumstance. Your friend needs to follow the fish-in cycle method (see my sig for the link).
Rules for fish-in cycle are pretty simple:
1) small number of fish - too late for that.
2) keep a close eye on ammonia and nitrite levels
3) water change to control high ammonia or nitrite levels
4) feed SMALL amounts of food, only feed every other day (maybe even every third day) - less food = less waste = less ammonia
5) gravel vac every water change to remove detritus
6) DON'T ADD CHEMICALS - these will be a short-term gain - long term loss. JUST DON'T DO IT. (All of the products you are mentioning will in fact lock away the ammonia for a while. BUT, they will not continue to do so - they have a certain amount of capacity, beyond that things can get bad. They can lead the uninitiated into a false sense of security and then it might be too late when the ammonia spikes. Second, these products will starve the bacteria that you want to cultivate in your filter. Not a good thing there either.)
Yes, Prime is a dechlorinating product. You need to have plenty of this product (or any other dechlorinating product) ready for all the massive water changes that are going to be needed to see this cycle through to the end. Ultimately, the only way to successfully complete a fish-in cycle is patience and a lot of water changes. Massive ones at times - to keep the ammonia and nitrite levels as close to zero as possible. Anytime either rises to 0.25ppm, you need to do a change big enough to drop it. Remove as much water as possible - down to the point that the fish can just swim upright - and add temp matched, dechlorinated water to refill. The bigger the change, the more effective it will be at keeping the levels down.
Rules for fish-in cycle are pretty simple:
1) small number of fish - too late for that.
2) keep a close eye on ammonia and nitrite levels
3) water change to control high ammonia or nitrite levels
4) feed SMALL amounts of food, only feed every other day (maybe even every third day) - less food = less waste = less ammonia
5) gravel vac every water change to remove detritus
6) DON'T ADD CHEMICALS - these will be a short-term gain - long term loss. JUST DON'T DO IT. (All of the products you are mentioning will in fact lock away the ammonia for a while. BUT, they will not continue to do so - they have a certain amount of capacity, beyond that things can get bad. They can lead the uninitiated into a false sense of security and then it might be too late when the ammonia spikes. Second, these products will starve the bacteria that you want to cultivate in your filter. Not a good thing there either.)
Yes, Prime is a dechlorinating product. You need to have plenty of this product (or any other dechlorinating product) ready for all the massive water changes that are going to be needed to see this cycle through to the end. Ultimately, the only way to successfully complete a fish-in cycle is patience and a lot of water changes. Massive ones at times - to keep the ammonia and nitrite levels as close to zero as possible. Anytime either rises to 0.25ppm, you need to do a change big enough to drop it. Remove as much water as possible - down to the point that the fish can just swim upright - and add temp matched, dechlorinated water to refill. The bigger the change, the more effective it will be at keeping the levels down.