Devastated and have to start over

[griss]

Random thought, could the rust off a stainless steel tool cause something like this?

IMO, that wouldn't do this much devastation. I regularly use razor blades to clean my glass. On occasion over the years, I've had to use an older somewhat rusty blade when I didn't have the foresight to buy new blades in time.

I guess it could depend on how much rust is getting in the tank but, I would think, the poly filters would remove anything from a rusty tool.

 

[Reefing102]

Using a rusty tool should be okay. Leaving a tool, screw, razor blade or similar to sit in the tank to rust could lead to issues.

You may consider an acid bath of your old rock to get that outer layer off

 

[Reefing102]

Also the algae issues may be attributed to nutrients bottoming out but I wouldn’t be overly concerned with correcting that until we figure out the main issue. If you don’t want to start completely over, you could run an ICP test and possibly an Aquabiomics test to see if there’s any major issues going element and bacterial wise