Welcome to the forum!
Are you using a buffer of any kind? You could always test the pH by adding tap water into a 5 gallon bucket and let it sit over night and test.
Also try starting a thread in the fresh water section you'll get more views.
"When creating an aqua scape, strive for the beauty of imperfection, as its art and there is no wrong or right, it's left open for interpretation" James Findley