a necessary evil

Ok before I get yelled at it had to be done. The bio balls in my bro's wet/dry were nitrate factories. Literally, they had fish gunk all over them cuz they weren't taken care of properly. So they got rinsed (more like sprayed with a hose) and then returned to the filter. They were probably out of it for 20 minutes, but the hose sprayed freshwater on them. I know, I feel the cringing, but it had to be done.

There is a zebra moray and a 4" spotted grouper in the tank (135 gallon). We did a 50% water change because the nitrates were so bad, so now they're in a pretty good range. (It looked like 10 at the most on the test strip)

We bought some biozyme to help the bacteria out. There was enough for 500 gallons. We dumped the whole thing in. (Dude at the fish store said to so if this was a no-no it's his fault):-[

Is the bacteria that the bio balls housed located any where else in the tank? Rock, sand, water, anything. The LFS dude said he'd watch for a spike but it might not happen, and that the eel and the grouper are hardy enough to deal with it. Obviously there are no more fish going in until the water is perfect.

The tank is in the process of changing from my brother's to my parents so it will definitely improve once they get complete control over it.

Anything you guys can think of besides watching the water params? I'm not expecting a full recycle, but I'm definitely watching it for a spike. BTW the tank has been up for close to 3 years (and in horrendous shape all 3).

 

So should I worry about this a ton or just a little?