pp treatments

Recently,I was out of town for 5 days and though I have a good fish sitter,taking care of my altums with minor tail fraying was too much for him and I arrived back to a considerably worsened situation. ( which he did not notice) Because of this I just had to do a couple of selected PP experimental treatments in addition to extreme cleaning proceedures and water changes ( I did two a day 60% water changes).
THese are the observations:
1.A treatment ( under supervision ) at 2mg/l which is 20 drops of my BIKA stock solution in a 10 gallon is fatal in 2 hours ..sudden death. THis dose is perfectly fine, even so mild I am not so sure it works, on discus.
2.A treatment of a 1/2 dose or 1mg/l is tolerated for 4 hours but the fish was visibly burned and died after 24 hours after being returned to the main. 1mg'l is faint enough in color that a ten gallon tank ,looked through from front to back, literally did not show pink. From end to end,though,it was pink.
I did not continue though a 1/4 dose ,if it would only work, is an option. THese two fish in the treatments were not at all at death's door and would not have died without the treatment.

The most effective thing that I did was to try to lower the ph more aggressively than ever before in the main tank...at least they seemed very comfortable. I do not know what the ph is for sure because of innacuracies that I found with my ph reagents which will result,I believe ,in me going with a PinPoint PH meter.
I also purchased and tested with an ELOS nitrate test kis..as always with this tank there was no trace of nitrate at all.

Regards Al