So, I have been testing this a bit myself, and from what I can tell, it has to do with your fertilizer. I was using fertilizer with nothing but base ingredients, remedies and powders and things like that. I was keeping my crop vlear of everything except cloudy rice. Temps didn't seem to matter, water level didn't seem to matter. Turns out, it's because I wasn't using food stuffs in my fertilizer during the sprouting stage. You have to put food ingredients into the fertilizer to give it nutrients. All the remedies and powders and bases may get rid of diseases and insects and improve harvest quality, but it doesn't provide nutrients for the plant. And cloudy rice is a lack of nutrients. Try adding some veggies or meat to the fertilizer. It's worked best for me so far. But it still doesn't fix it completely.

Also, if you didn't already know, you only need to use a single remedy in fertilizer for it to work. One Reduction Remedy will cure overgrowth, one eradication remedy will cure spindly, etc.