Reusing Star San

I switched to Star-San earlier this year and have been pretty happy with the product overall. However, having just recently bottled up ten gallons of Russian Imperial Stout, and looking at bottling a five gallon batch of lambic and a few assorted other brews, I stand to keep using the stuff at a pretty quick rate. I'm on my second large bottle this year and it definitely adds up. 

I'd read in a few places that one can re-use it as long as the pH stays below 4 (although 3 seems better if you can store that strong of an acid) and it's clear.

So here's my plan to start doing so:

• Buy some pH test strips which read down into the 2.x range
• Mix it with distilled water instead of tap water
• Store it in an unused, PBW'd corny keg or a heavy duty plastic bucket with a lid
• Test the pH before each use and either add more concentrated Star San if it's still clear or dump and start over if the liquid is cloudy

Anyone else out there had experience with this? I'll follow up on how it works for me.