Another wave maker saga. Now what?

[MDAquatics]

So despite having a guard on my wave maker, the poor little fella managed to squeeze his way in, he's a goner. This is my office tank. I came in this morning to find the return chamber almost dry so I started topping it off and realized I was just overflowing the tank. From there I pulled the filter cup and realized water wasn't going through it, I pulled the fleece and found it was covered in slime. So I washed everything and returned it and started looking for my nem.
I was confused I couldn't find him because I know I have a guard and he didn't make it into the return, I checked anyway and found him. Maybe I didn't have the guard seated well enough, not sure.
As expected, water is cloudy and corals aren't happy. I'm shooting for a 100% water change now when I can run home and grab some RODI to mix. Anyone think I should handle it differently?

 

[blaxsun]

Sounds like a solid plan. Dang anemones...

 

[Gundy]

This is exactly why I’m not wanting to get an anemone. I want one but will it get through the guard? Has anyone figured out how to avoid this from happening?

 

[Townes_Van_Camp]

This is exactly why I’m not wanting to get an anemone. I want one but will it get through the guard? Has anyone figured out how to avoid this from happening?

Put your wave maker in the dark?