Added carbon to my filter.

[Fishchicago]

So today I planned on changing my substrate. But last night was a crazy night. I was looking into my tank around 2 a.m and noticed my discus hugging the bottom breathing heavy and looked very lethargic, they also went very pale and the 2 discus that have striped... there strips became very dark. One even darted straight into the ground and looked like he died, the discus were just laying against the bottom looked like the beginning to a horror film. I ran an instant water test. All peramiters were 0 and my p.h was 7.4. So, I instantly did a 70ish percent water change back to back, added 2 tbls of salt for ever 10 gallons at the end, crossed my fingers and went to sleep. Today I woke up and saw that everything is fine they are back to normal eating swimming and fighting for territory all good things. I feed them 3 times a day, morning my own beef heart recipe. After noon blood worms and again at night a little more blood worms.

So I ran an analysis thinking what the heck did I do for this to happen so quickly, and the only thing I did was I went to the fish store to get carbon to remove the tannins out of my water from my drift wood. Originally I do not run carbon. Just sponges in my filters. So the guy at the store said this is amazing stuff your fish will love it. Maybe I put to much into the filters, I also filled my own bags with the carbon, maybe I used to much? Did it kill something in the water for the discus to feel this way? Anyway I took all the carbon out before my water change last night and went back to the set up I had. I am not freaking out, it's a very new learning experience for me, and each day I understand more and more, maybe I dove in over my head, but its helping me learn faster because now the goal is to keep the fish alive and healthy. Again thank you for your time and any response is greatly appreciated.
The product was: Activated Carbon. By aquarium adventure. I am just trying to figure out why they acted like this and my only reason is the new carbon addition.

[LizStreithorst]

I can't see how it could have been the carbon. When you looked at them at 2 am are you sure they weren't just sleeping? The one that darted may have been startled when you woke it up. Just guessing...

[Fishchicago]

I have checked on them when they sleep for the last two weeks. Normally they hover and do not get spooked when I turn the lights on. Last night they were laying into the driftwood sideways. Colors were terrible. I am not sure I guess time will tell. Maybe they were just in a deep sleep. When I started the water change last night they were immediately better once I started adding in the new water. I wish I took a picture but I didnt even have time I just went right to work.

[FishFanMan]

I use probably 2 cups of carbon in my 75 gallon tank. I replace it monthly. Never had any problems with my discus.

[JamesW]

I can't see how it could have been the carbon. When you looked at them at 2 am are you sure they weren't just sleeping? The one that darted may have been startled when you woke it up. Just guessing...

This! When I'm asleep I certainly don't look my best. Hair messed, drooling, snoring, you discus don't either.

That said, did you rinse your carbon? While I think they were just sleeping and the 75% W/C woke them up some carbons have fine powders that could potentially irritate them.

My money is on circadian rhythm.