Thank you Patty for your kind words and comments .
I don't recall if you said thanks back then , but knowing how kind and caring person you are , I'm pretty sure you've done it .
It's not harmfull as far my experience with the slime buidup goes Kim , but it looks nasty and I always want to play on the safe side and keep things as sterile as I can .
Yes .definitely add dechlor prior the WC . Why expose your discus on chlorine or chloramine levels even if your refill time is only 10- 20 minutes . Beneficial bacteria will suffer loss too, if your filters are running while you pour chlorinated water in your tank .
This is not true Brian .According to Seachem labaratories Safe and prime interact with the organics and toxins in the tank water too and they weaken its strength to deal with the tap chloramines /chlorines .That's why they advise that it's safer to add a full tank dose and avoid any chloramines left unchecked .
Tank dosing prior WC - full tank volume ,
Aging barrel dosing prior a WC - only the volume of the new water .
Agree with Willie . It's not wise to test their immunity on a regular basis . Even if they show discomfort only for a 20 minutes it's not something you should ignore .