Discus Blackened, And Dying.

[TwoTankAmin]

I would not put painted stuff like that in a tank. However, when one puts toxic chemicals into a tank they do not killed slowly over time that I have seen. They kill a lot of fish very fast. PVC cement should be fine, if you have pvc pipes in your house, your water runs through cemented pipes on its way yo your tank.
 
Sophie and zante- here is a picture of one amazon sword in my 75 gal (280L) tank. Its 21 in (54 cm) deep.

 
The OP changes 30% a week and has 3 large plants and 0 nitrates is suspicious? Not to me. Especially if you look at the picture he posted where you can see part of one sword.

 

[Sophie]

I would not put painted stuff like that in a tank. However, when one puts toxic chemicals into a tank they do not killed slowly over time that I have seen. They kill a lot of fish very fast.
 
Sophie and zante- here is a picture of one amazon sword in my 75 gal (280L) tank. Its 21 in (54 cm) deep.

Ah - yes I appreciate they can be very hefty especially when deeply rooted too. I think I get confused with people's perceptions on what's heavily planted.

 

[chaz61998]

All my other fish seem fine besides the discus. No signs of issues. In fact, last week my rams laid eggs. So it can't be that bad.

 

[chaz61998]

UPDATE: Snail just died as well. It must not be discus plague.

 

[Sophie]

Try taking out everything that you've painted and DIY'd and then do a large water change and see what happens?