well i know peat moss already has a low ph level of like 3.5ish so your best bet is to repot with a good potting mix. i use 1 1/2-2 bags of foam rock, 1/2 bag of peat moss, a bag of MG organic soil, and some chicken shit. mix it all together in a 30 gallon rubbermaid bin add a lil bit of clean water and let it sit for a week or 2 mixing it everyday and checking PH. my mix usually gives me a ph level of 6.2-6.8 depending on how long it sits. when i repot i lay a inch of foam rock in each pot for better drainage.