Yes and no. As I understand it, it is best to not have your sparge water pH below 6 (7 preffered) as, depending on your grist, the grain you are sparging may not have the buffering capacity to counter a low, or high, pH.
I used to treat my HLT with 5.2 and, via pH papers, could see it work. However, I stopped becuse I was also seeing a higher rate of sedimentation in my HLT thus requiring more rigourous cleaning.
Now, I use Lactic Acid as a amendment to pH and find that a mere 4 mL/14gal can bring my avg pH 9.3 water to pH 7 with no alteration in taste. Now, I just use the 5.2 in the mash and my HLT is happier (cleaner) for it.