I have been under the idea that the substrate in our planted tank never needed to be siphoned because plants will utilize the fish waste & left over fish food in the substrate as a source of nutrient. Therefore, I have not been siphon the substrate in my tank for the past 3 month, not even once.
I have lemon tetras, cardinals and rainbow in the tank. They seem to be fine except I do see flashing and fish scratching sometimes. But they are all eating and active.
BTW, I treated tank with ICK in Jan while I am transferring everything from a 38G to a 75G. So I treated the tank with Super Ich Cure. Now there are no more white spots on the fish.
I decided to keep discus in this planted tank a week ago and added two very heathly adult discus in the tank. It was a bad idea and both discus truned dark and started scratching with rapid breathing within 24 hours in my planted tank. I knew it is the water. So I started siphon substrate and the water I got was like sewage water and stink really bad.
I have been sihponing the substrate three times since last week and have been doing 60% w/c every time I siphon the substrate. Now I'm scarred of putting my discus back into the tank.
The substrate consisted of Miracle Gro Organic Potting Soil with Eco-Complete. Should I ditch the substrate and start over? I'm currently treating the tank with Praziquantel and the treatment has been ongoing for a week already. But I still see tetras scratching sometime and rapid breathing as well.
I dont trust the water anymore. At least they are not good enough for discus. What should I do?
Furthermore, I did put new fish into this tank without QT before, so I'm responsible for all the ongoing issues with my tank. I want to kick myself for that.