Hi, I am new to this forum.

I have a 450L planted community tank with the following fish

4 X 6" Discus
2 X 5" Discus
3 X 3" Discus
2 X 2" Discus
4 X German Blue Rams
10 X Rummy Nose Tetra
9 X Neon Tetra
8 X Bristlenose Catfish

pH: 6.4 to 6.6
KH: 6
Ammonia: 0
Nitrite: 0
Nitrate: 0
Temp: 30 C

The 4 X 6" Discus have had a terrible case of fungus and fin rot. One
Of them has a pop eye as well. I initially treated them with Pimafix and Melafix for 3 days but things got worst. I started treating them with Blue Planet Tri Sulpha (Full Dose: 11 Tablets for 440L) yesterday and things looked better today but it must be affecting the biological filter as the ammonia in the tank was about .75 ppm for the first time in the tank.

All other fish in the tank are doing well.

I have done a 75% water change today and raised the temp to 32 C.

Do I need to redose after the water change? The instructions on the Tri Sulpha is very brief. It says to use 1 tablet for 40 L and redose if necessary after 3 days.
Please help.