Never seen this before in 30 years of owning freshwater tanks

[AquariumStuffs]

Hey!

If you are changing the new filter media, a good practice is to never change it unless it is kind of falling apart completely. You see, by changing into a new media completely you are getting rid of the good bacteria and it has an ironically negative effect on the cycle of your aquarium. Try rinsing the media in water from an old but well-cycled tank when you are conducting the water changes.

If you still want to get a new filter, rinse the media along with old media filters so the new filter also receives the good bacteria. This will surely prevent the tiny cycle that occurred when you used a new filter. The thing is every time you change into a filter, you will experience a tiny cycle as the new filter needs to develop some of the beneficial bacteria. Similarly, it is for the same reason, boiling the aquarium décor and cleaning the gravel is not helping.

In the worst-case scenario, you can try using a UV sterilizer to stir clear of the bacterial bloom in case the cloudiness or slightly reduced. I experienced the same dilemma and after I used the strategy, the aquarium cleared in under 24 hours.

 

[Fishiemang]

I got that same colored glo fish gravel in my 38 bowfront. It's not from that. I never had that issue. I started that tank in probably the exact same Glo-Fish 10 gallon starter kit. Did it for my kid. That water condition is not fron the gravel, the filter or any of that.

However...

Using the tank light as a night light isn't the greatest idea....at least white light. Get a light that has a blue night setting for night light. It's bright enough....there are many options out there l, as I am sure you know, for this. Can get automated ones from Fluval or Marineland, to manual switch style as well from just about a zillion manufacturers. But get one that has a blue light setting if you want to use it as a night light.

Here's the kicker....

Make sure the kiddo is not adding things like extra food to the tank...like leftover hot dogs, or ya know...the crazy stuff kids do.

What I see in your pics is no night time for the tank, so you have unlimited light, and plenty of nutes causing algae bloom.

Plant the tank with some plants directly into that gravel. I don't see anything in there that will make that an issue...