Water changes can cause additional blooms of algae or even bacteria (cloudy water). If it does, there is probably a good source of nutrients in either the substrate or in the fresh water you are adding. But it is probably not in the fresh water.
I would do a good cleaning of the gravel, using a Python. And if your water really is not the source of the nutrients, as it probably is not, although if it is phosphate, it might be, I would do at least a 90% water change and probably do it daily for a two or three days. (Phosphates also come in the food you feed.) One or two 90+% water changes should do the trick. But pay attention to the changes in temperature and pH. If the new water is not at the same temperature and pH, you might want to do a couple of 50% water changes first to get the pH in the tank so it is more like that of the fresh water. And if possible mix hot and cold water taps to get the temperature where it should be.
If that does not work, you might consider taking the tank down and starting over after cleaning the gravel and tank and filter. In other words a 100% water change with a deep cleaning of the rug (gravel) and filters.
