Java moss walls

So Im making some little walls to go in my shrimp tank to plant java moss on and a couple to glue anubias/ect on. Ive seen someone use spaghnum moss as a substrate for the java moss to root in, but seen that it can lower pH. Does it lower it badly that I need to not use it? If so, what is another medium I can use or how can I combat it? Im setting up a 3 gallon for some black neocardinias and some kind of snail. I also want to use this method to make a couple java moss resting pads for a betta tank im setting up but that will be on a much smaller scale. Can also share how I made the frames for the walls if anyone is interested. I used egg crate ceiling tile and cross stich backing