I think it's the best for the job we want it for. With 2.5ml per 100 liters, it provides quite a few water changes.

I use it in water preparation before every change and it works much better and faster than anything else I have tried so far. Excellent product.

Yes, it is expensive, but you get what you pay for. It requires adding a minimal amount to the water compared to similar products.

I have been using it for years, I would say it is the best on the market, as well as expensive for its price, but in many liters/aquariums I don't think anything else would be more cost-effective.
*It also neutralizes ammonia with the appropriate dosage indicated on the bottle.

Excellent product. The price is a bit high, but it is truly worth its money. I highly recommend it.

Because it is not clearly stated anywhere, it has 2 functions. One, of course, is for neutralizing chlorine, etc. when changing water. The other, and very important, is when for any reason ammonia levels exceed the limit, you add a dose of prime every second day for every 1ppm of ammonia and it neutralizes it, making it non-toxic for the fish (for example, for 0.75 ppm, we will add one dose for the liters of our aquarium, for 1.5 ppm of ammonia, 2 doses for our liters, etc.). This way, it gives you time for the aquarium to return to balance without poisoning and killing the fish.

Yes, it may be more expensive than the others, but having used almost all brands, I believe it is the best. It is also very concentrated, so the liter-fluid ratios are much better compared to the competition.