Lowering Ph For Licorice Gouramies

HI everyone! The Wet Spot tropical fish is carrying Parosphromenus nagyI licorice gouramies currently, and I intend to get and spawn a trio of them. Here's my question...I would prefer my tank's PH to be no higher than 5 to better emulate their natural habitat, but plain distilled or RODI water has a PH of about 6. What can I use to reduce the PH without sending the TDS (which needs to be 30 ppm or lower...50 microsiemens for those who use conductivity) skyrocketing up? Thanks

 

a few sites say to use phosphoric acid.

 

Anything else I can use? Would rather not play with dangerous chemicals

 

a few of the sites said peat moss can lower pH, but it is not environmentally friendly.

and a few said Indian Almond leaves and driftwood.

 

OK. Thanks

 

Would the PH down stuff sold by API work? It's 9.6 percent sulphuric acid.