First you should know, I have only basic knowledge of fish care, I am a beginner to having an aquarium.
There is a white wavey fungus all over my tank! 5 of my fish have died covered in a white cotten-y looking stuff. they woud not eat and tend to stay in one spot. When I first noticed it I didn't think anything of it. Then later the same day my pleco was dead, then my two glo tetra's were covered in white spots, which I assumed was ich. I treated them for ich and the next day they were dead. After that, my tiger barb would not eat or even move out of where he was floating. The next day he had died. Now, just today one of my gourmi's had died. My other gourmi has not been effected by this what so ever. I have taken him out of the tank and bought fungus clear and treated the tank, washed everything in hot water, and basically re-started my tank as if it were new. I am still having this issue. Also, my pH is high and I have no idea how to fix this, I had bought some pH correcter as well but, it is still to alkiline.
Any advice will help!!
You need to cycle your tank. it takes about 6 weeks to cycle a tank if you have fish it may take longer and you will have to do many water changes at least once every day or two. If you no longer have fish just keep feeding your tank fish food with no water changes.
A test kit for ammonia, nitrite and nitrate will help you know when your tank is done cycling.