Amolock product

Question
Thank you, the rest of the fish seem fine.
Have you ever used a product like Ammo-lock?
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The text above is a follow-up to ...

-----Question-----
Question, one of my angels out of 5 in a 30GL tank has been inactive for 2 days and was sitting in the corner of the tank, until it died today. All of my Angels are small in size. The tank is 2 months and 1 week old.
I used amolock in my tank a week a go and all my test readings are off. from what I see the rest of the fish are doing fine.
What do you think?

-----Answer-----
With not mentioning any external symptoms of the fish that was ill,test your water for ammonia, nitrate, nitrite, and pH to find out where you are at. If your levels had been high for some time and the fish had gotten used to the conditions sudden change can cause death in fish because it is simply to stressful. Before adding any type of product that could alter your water chemistry it is always a good rule of thumb to see where things are so you can reduce levels if they are to high at a gradual rate rather than to much to soon. Happy fish keeping!!

Answer
Yes I have used AmmoLock with some of the back filters I have owned being their cartridge only held the activated carbon. I have found it to work but I always test my water prior to adding it or I simply start my tanks out using it from the beginning. Happy fish keeping!!