75 gal suddenly cloudy?

I just disassembled the eheim and cleaned it out. It was a little grungy in there, but nothing spectacular. I'm not going to do the whisper at this point since I don't want to make anything crazy happen with the cycle. I did rinse some of the media in hot water, the rest in the clean tank water. So I'm sure I killed some bacteria, but not all hopefully. I replaced the fiber filter pad that was in there (the one that was there was permanently brown), but the rest are the originals that I put back in.

I guess we'll see what happens with it in the next few hours now that that filter has been completely cleaned out.
 
Maybe there's something down in the sand decaying, since you're only vacuuming the top there could be something down in the substrate.
 
I'm not noticing a significant change, but maybe it's a little clearer?? I'll see what it looks like by morning and go from there. I'm afraid I'm just being hopeful that it's clearer. It's definitely still cloudier than the other two tanks. I also know the glass is not in as good of shape (a lot of little scuffs, etc), so I don't necessarily expect it to be as pristine as the other two, but I have seen it clearer than this, so I know this is not where it should be.
 
So the answer is... after two days since the cleanout of the filter, the tank is still cloudy. Obviously that was not the culprit.

Now I'm back to not having anyway to explain the cloudiness.

I'm still counting all my fish, and everyone is still present and accounted for. I did have one fish go missing back in December (the original group of mollies that I added, one did not survive), and I never did find a body. There are no ornaments. The only decor in the tank are two pieces of driftwood, which have no holes for a fish body to get caught in (I've checked and nothing is under them), two clay pots (which I can see through from outside the tank, and which neither one have a body in), and plants (again, no body in the plants). So I really don't know what to do next.
 
Do you/can you get a micron filter?? HOT mags have a micron filter.

Maybe floating "white" algae??. but still think it is bacteria.
 
I have no idea what a "micron" filter is, but will see if I can hunt one down. I have to go to PetSmart tonight anyhow for cat food, and am going to look for some filter floss as well. Will check into the micron filter and see if they've got something at a reasonable price.
 
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