Sudden Cloudiness To Three Tanks

[Atstehley]

I have three tanks, a 20 gallon glo-fish tank, a 50 gallon turtle tank, and a 10 gallon snail tank (currently housing only baby snails from the Glo-Fish tank). I do regular, weekly maintenance on all three, doing a 25% water change. They all have perfect quality, minus hardness due to tap quality. In the past few weeks, I've noticed that all three are getting cloudier and cloudier. I haven't changed anything since these tanks have been started months (2 years for the turtle) ago. Any ideas? I also lost 3 of my 5 snails suddenly last week.
Ph is 6.8 - Ammonia 0 - nitrite 0- nitrate just above 20

 

[Desperado070]

colour?

 

[Atstehley]

I'd say a very light green haze in this picture because I'm just about to do the weekly maintenance, but it's been just a slight milky color. https://photos.app.goo.gl/krvBUv8qhcDvCvBb6

 

[Atstehley]

https://photos.app.goo.gl/FxHtAMbY2jEWvrNZA it's usually a slight milky haze, it's a little green because today is maintenance day.