After 5 tank changes, I think it's safe to say that the type of tank isn't the problem. It could be the dired blood worms. I know that can cloud up water over time. It could also be dust from the gravel you are using. If it is cheap then you may have to rinse it a few times. The final possiblity is time. It could just take time for the dust to settle to the bottom and the water to clear.
Unless there is something really wrong with the water, I would let it be foggy and wait to see if it clears up over time. If you are really annoyed by it you can do multiple water changes until it clears up. I also noticed that his stomach is a bit on the big sized. Did he just finish eating before you took the picture? If not, it could be a simple case of crashed water quality. If he isn't eating all his food or it makes him bloat, you can cut back the treats to once a week instead of 3 times a week.
Personally, I wouldn't worry about the cloudy water more than the bloating. If I'm wrong and the tummy just looks big because of the angle, then nevermind. But if he is bloated then he is definitely getting too many dried blood worms or he can't digest them. Maybe switching to frozen or live bloodworms could help.
If none of that works, then I'm out of ideas. Can you ignore the fogginess if the parameters are good? :(