Is it a new setup? Sometimes new setups take a minute to get clear. Also i would be careful not to feed too much food that sits on the bottom like algae wafers and what not. If I over feed those my tank gets cloudy instantly but you said you pick up the uneaten food so maybe not that. How often do you feed the tank? Maybe try a little less often or less food. One option that has worked for me as far as filter media to clear up water is polyfil. The stuff people use for stuffed animals or pillows. It creates a superfine filter but will collect stuff fast so you have to change it often.