You’re right about rainwater…no need to dechlorinate something that should never have chlorine in the first place! However, I also use a water distiller to produce some of my water, and I am unsure whether this device would allow any chlorine/chloramines to remain in the distilled water that remains. In any case, failing to notice this flaw with my dechlorinator seems to be what undid all my prior efforts to make good licorice gourami water…I think I will switch back to using chiefly rainwater as long as the TDS meter shows it to be fairly clean (my prior attempt came after a long dry spell and captured an incredible amount of pollutants that hiked the TDS up)
Consider this ordeal practice if I ever go to ornaticauda or parvulus…