As I tell everyone accurate pH level is not an absolute requirement for any kind. The fish we buy at our LFS are tank bred thus enabling them to handle wide range of pH levels within suitable UCL and LCL. That is unless you are trying to breed your Gouramis. In that case, what type of Gouramis?
Note: The pH level is the number of +ve or -ve ion in the water, thus indicating acidity or alkalinity of the liquid.
I have kept and bred cichlids in both in lower and higher pH levels, while I have kept both guppiesm platies with neon tetras successfully.
I would strongly recomend not changing your pH level in your tank.
Rohn