Rust on carbon bag

[Darwin]

Couple weeks back it was time to change out carbon and I was fresh out. It was late and all my local lfs were closed. Decided to go to petco and just pick up some fluval prebagged activated carbon ( I run a 13.5). A week or so in I realized 1 particular rack of zoa frags were closed for most parts peeking here and there. Had a colony of buttkissers, white zombiesand bow tie blasters melt away. Now this rack is the directly across from the return, not close enough to get blasted but enough see some sway. Today I started running reef flux for a small bryopsis issue I have. In removing the carbon bag, I found what I believe are rust spots, ran magnet thru the carbon and picked up some “carbon”. Could this be cause of my zoas depleting and melting. All other colonies are doing well. Any thoughts? Btw my apologies if I posted this in the wrong area, thanks in advance

 

[Reef.]

You don’t have black sand do you? That can have issues with it.

If it’s from the carbon that’s not good, and yes that could well be the issue with the zoa, if it wasn’t, it would have caused a different issue anyway, so good you found it in time.

 

[old salt reefer]

I use the frugal and the bags do the same for me(rust colored spots), bare bottom tanks. My Zoas just fine and I've been using it for over a year, change it every 2 weeks.

I use the 45 gram bags. Come 3 to a box.

 

[Glass Algae]

Can u post a link to the type of carbon packet?? I use Fluval prebagged as well

 

[Darwin]

Can u post a link to the type of carbon packet?? I use Fluval prebagged as well

fluval edge carbon filter - Google Search

 

[Tastee]

If you are concerned about metals etc in the water then running some Poly Filter may be a good idea. It adsorbs many compounds and will change colour depending on what it adsorbs. If all is good it will just gradually turn dark brown, but if it shows other colours it indicates those compounds are present (and removes them).