Hi Everyone,
I've had some diseases issues recently -I've posted about them in my post on quarantine regimes in General Discussion.

My surviving goldfish are now ready for release into the big tank. There are three danios and two marbled sucking cats that have been in the big tank the whole time and are healthy.

I'm just worried about reintroducing the survivors and there being residual nasties in the big tank. I think I had a bacterial disease issue but I can't eliminate parasites.. I did have one brief moment with fish lice.

Can anyone recommend a regime that would make the big tank as safe as possible?

I've started a three day Melafix/Pimafix dose but was thinking of a Prazi treatment as well. What do people think?

Depends how brutal you want to do it. may not be helpfull, but I decontaminate used tanks I buy using bleach. I throw away any filter media that they have, as well as rinse out the gravel in bleach. I use 20:1 water to bleach ratio, and rinse it many many times afterwards. Extremely time consuming! I guarantee, there will be nothing left after that . If you want a softer approach that doesn't involve killing everything possible, you should wait for more replies.

Take out all gravel from the tank and boil it for 30 minutes. Through away the filter media. Fill the tank with water up to the rim with the filters still running. Put fish nets, decorations, and tubing insided the tank. Add enough potassium permanganate until you cannot see through the tank. Let it stand for 5 days. If anytime during this period, the color of the water turns slightly brown then add more potassium permanganate. After 5 days, empty the tank and rinse it well. Let it dry. Spray 70% isopropanol solution all over the tank and let it evaporate. You got yourself a sterile tank!

NOte: if you cannot get solid potassium permanganate, buy clear water from jungle labs which is a solution of pot perm.

I think brutal is the way to go... better safe than sorry... so I will break the tank down.

I have plants as well - so they can have a mild bleach bath!

I will relocate the fishies of course.

Looks like I get to cycle my tank again

One question - if I have sponges and noodles, can they have the 'treatment' along with the tank or is it better to start again?

Not sure about the filter media, but I would say its okay to kill it using bleach or potassium permanganate. potassium permanganate at the level where you cannot see the other side of the tank as kingyo said is just as good as bleach.

I always dip quickly (no more than 30sec-1 min) my plants when I get them, to make sure no nasty surprises come along with it. Too long and your plant will die and/or turn white.

Either method, make sure to rinse it really really well

Thanks for your responses folks - I really want to ensure that I don't get more problems that I can prevent if at all possible.

Just scored myself a Kilo (2.2 pounds) of PP from the local stock feed supplier - way cheaper than the chemist or aquarium shop.

Don't go buying any Kat - I think I have enough to supply the Canberra member of this forum for a lifetime..

Excellent, sounds like you've got yourself a good PP deal (to an outsider it might sound like you're a PP addict or something )! I've never used PP before (just salt, and more salt LOL) for my minimalistic decontaminations, so you'll have to let us know how you go there Good luck!