new QT water or Re-use?

[Gregs]

Ive set up my 220g fowlr and now im in the proccess of stocking up fish. I have setup two 33g QT's for this and was wondering if there is a method to shock or treat the water somehow to kill anything left in the water and just reuse it for the next fish?
wondering if a heavy copperdose for a few days would suffice then clear it out with carbon?? temperature drops/raise? cleaning out the tanks between fish and mixing up a new batch of water is a PITA so im wondering what you folk all do.
Thnx

[Aquattro]

I would use new water. Sick fish are more a PITA than making water. Which sounds simple enough, fill tank with water, add salt, mix.

[Gregs]

well not quite. because you still need to rinse the tank out and give it a good scrub, even then cysts and other parasites could survive a simple rinse. so i let the tanks dry out then fill with hot water/balance with cold water. then let it sit in fresh water for a few days before i mix salt.
so its quite a process compared to... just doing a super copper treatment instead for example? that is probably just as effective or even more...

[jorjef]

This could be short sighted and way off but if you are QT'ing a fish and and shows no signs of illness or if you just treat with something broad spectrum why would you need to change water. Wouldn't you be killing what ever the broad spectrum treatment covers and if the fish did develop something that wasn't covered you would treat for it until it clears...That being said I never have had a QT tank so......

[Aquattro]

My treatment tank is about 25g, so for the best start, I'd use new water. I've never used a treatment tank before, but I now put the fish in, treat with a standard dose of CP for a couple weeks, and transfer fish to DT. I would then empty it, give it a wipe with a towel, and leave it until I get another fish. Repeat. I don't want to maintain a running tank as a q tank, as I don't regularly purchase fish. Since I treat for ich/velvet/brook regardless, I'm not worried about spores.
Bringing a new fish in, I want the cleanest water to start.

If you Q fish and don't treat, I assume there are no cysts to worry about. If you previously treated with copper, then you either mix dosages going forward, or you use carbon to remove it. Waste of perfectly good carbon

Ultimately a personal choice, but for me, I'll just make clean water.

[George]

Originally Posted by jorjef

This could be short sighted and way off but if you are QT'ing a fish and and shows no signs of illness or if you just treat with something broad spectrum why would you need to change water. Wouldn't you be killing what ever the broad spectrum treatment covers and if the fish did develop something that wasn't covered you would treat for it until it clears...That being said I never have had a QT tank so......

It's more complicated than that. First of all, when people talking about broad spectrum in fish world, they are referring to antibiotics, both gram-positive and gram-negative antibiotics.
Then there are nasty stuff that are not bacterial, like parasites, virus, and such that don't react to antibiotics. You need some other medicines for them.
For some parasites, when they are in cyst stage, no known medicine can kill them (at least no medicine that you and I can get our hands on). And the cysts can survie some extreme condidion like high temp and very low salinity.
It's a good practice to clean your QT tanks and change all water after one round of QT.