High ammonia, low pH

Question
The computer would not let me ask another follow-up question but when we
last corresponded my levels were as follows- 1.0 ammonia, 0 nitrite, 5.0
nitrate.  There was a slight white film on my rocks and my superhero of a
Blue Gourami was still visibly healthy.  You wanted me to test the levels again,
which I did, and there was still no trace of nitrites.  So I brought the water to
my fish store and he said that the pH is off the charts low but there is no
ammonia, nitrites, or nitrates!!!  I was so shocked that I had him test a second
time with a different carton of sticks.  I look forward to hearing your take on
this.  I bought a pH fixer but I will wait to hear your feedback before using it.  
Does this help explain the white gunk?  Thanks for your help!

Answer
Hi Heather:  I do not like those test sticks... I prefer the glass vial and the solution that you add.  I find them to be more accurate.  I know this is a pain and if this were me I would find a store that uses the vials and solution to test my water.  If that is not possible then we will have to consider the facts that we have to work with.  What was the pH ????   You can use coral gravel to raise the pH of tank water.  1 pound per each ten gallons of water.  I add in 1/4 pound of coral gravel per 24 hour period and monitor the pH an hour later and then again the next day.  If the pH is still low then I add in one more 1/4 lb segment of coral gravel and I repeat the process of testing and adding until the pH reaches about 6.8.   Keep me posted... dave