All my parameter are good (no ammonia, nitrite and very little nitrate.  I do weekly water changes.  

Thanks.  

At first my floating plants were getting moldy on the tops. Sort of like white speckles. I'd just kept throwing out the one effected but it just kept coming back. Till I gave up and threw them out with an exception of a few good ones with I put in a tank in a separate room.  No more mold. And some with mold in an empty tank.  I let the mold go and then tried spraying stuff on the surface of the plants.  A regular light mist of diluted hydrogen peroxide eventually did the trick. With some plant die off. It's possible a mist of a antil fungal med for the aquarium could have worked.

Then I kept getting what I thought was a fungus on the bottom and other odd areas. It looked like some of the funguses but wasn't. Adding an antifungal does kill mold but not well enough unless you target it.  Added a little tank water and the meds and turkey basted it several days in a row.

At least not seen. Reduced feeding, added an air stone, made sure the take was covered and got an air purifier. Skipped a week and did the treatment again.

I'm sure it's just waiting for the right time to come back. But at least I didn't have to tear down the tank and sterilize it.

Hope that helps someone!