It should be used with every water change.
Api water conditioner vs prime.
Both are ideal for use with prime.
It also detoxifies heavy metals in tap water.
I ve not used it but i have used other live bacteria products such as microbe lift.
Ask any aquarist to recommend a good water conditioner and seachem prime will likely be the response.
Api tap water conditioner similar to the seachem api tap water conditioner will remove chlorine from the tap water and will also work to eliminate heavy metals and chloramine.
Quickstart is a live bacteria product that is as you said used to decrease cycling time.
If you use a water conditioner with your aquarium then you are likely nodding along at my top pick.
When adding new fish use stability.
At the very least tap water conditioners neutralize chlorine and chloramine which are disinfectants commonly used in municipal water supplies.
When transporting or quarantining fish use seachem stressguard.
50 ml 100 ml 250 ml 500 ml 1 l 2 l 4 l.
Stress coat prime and lots of other things are called tap water conditioners.
The formula of api tap water conditioner incredibly concentrated.
Some water conditioners like stress coat also neutralize heavy metals and help replace damaged slime coats.
As you said prime is a water conditioner one of the best imo that neutralizes ammonia and other toxins from your water.
Not only is seachem prime a complete conditioner but i found that it lasts the longest.
You will want to use only a drop per gallon 3 8 litre as it is very strong.
This conditioner comes in liquid form.
Use at start up and whenever adding or replacing water.
It will also detoxify any heavy metals found in the tap water at typical concentration levels.