Hi Phil,
Im starting the treatment of my change water tonight as you have recommended. I have had trouble with bacterial infection in my fry grow out tank. I have been using Hcl for a good while now to adjust my ph after getting the tip from Illusn. It is definitely cost effective compared to some of the other methods.
I've just filled my barrel from the tap and have added the half of a 1/4 teaspoon of PP. Am I right in saying that I should leave it for 24hours with the air stone to move it around, then add my preferred chlorine/chloramine/metals etc remover (Supachlor) after that 24hr period so as not to interfere with the PP? Then also add the usual amount of Hcl to adjust my ph? Probably leave another day with the heater in it to bring it up to temp and then add the hydrogen peroxide to the barrel shortly before doing the water change? Is that right with the hydrogen peroxide, I add to the barrel just before the water change?
What I had been doing is fill my barrel and add the Supachlor and Hcl at the start, aerate, leave for 24hrs and then use after coming up to temp. My breeders are back in the display tank now and generally still lay weekly so seem fairly happy (except for being put back in the display). Its just my fry seem so susceptible to bacteria despite 50% daily changes and a good cleaning regime. The addition of a simple bacterial treatment to the water at the start seems a great idea.
Thanks for your time Phil, very much appreciated,

Cheers