My axolotls tank water suddenly got cloudy!

[The Duck]

I have 2 4in long axolotls, and ive had them for about 2 months. Every things been going fine until a few days ago, where i added some water to their tank, and the whole tank got really, really cloudy. The axolotls seem fine, but im wondering, what might be making the tank water so cloudy?

 

[lea]

Have you tested the water parameters???

 

[Jennewt]

In the 2 months since you set up the tank, have you removed any water from it? The answer should be "yes". Did you dechlorinate the water before adding it?