Is StarSan less effective if hard or alkaline water is used?

Quick question for the group:
Is StarSan less effective if I use my hard/alkaline water profile rather than RO water? 
I’m brewing today, so I’m too lazy to do the math.  I have JEA Water (Jacksonville, FL; already posted in "Post your water report’).  RA = 46.
I used RO water today to make up some fresh StarSan, anyway.

I have never seen a number/graph  for effectiveness vs Alkalinity or RA, but the SS solutions I make will go cloudy quickly with my tap water, HCO3=364 ppm, RA =197.

You want the pH at 3 or so to be effective.  I should get out my meter and measure SS in RO vs. tap water sometime.

For your brew session it should be fine, but using RO water will definitely extend the life of your starsan. Whenever I would mix up a batch with tap water, it would turn cloudy almost immediately which is a sign of it losing its effectiveness (but a PH test showed it was still in the 3 range). Using RO, it’ll stay clear for weeks, and theoretically effective.

Good to know.  I suspected as much.  It takes awhile for the brew light bulb to go off, sometimes! 
I spent the last 6 months trying to understand my water profile (and why my beers [pale and amber] tasted so bad and bitter), now it got me thinking about the StarSan solution, too.
Why not the same problem?

If my water is really alkaline, wont’t that “neutralize or buffer” the acidity of the StarSan solution and make it less effective?

This brew session is the first time I’ve used RO water (but, if I’m right, it’s the best $1.50 I’ve spent [30 cents per gallon at the local grocery store] to make a batch of sanitizer).

I have the same problem with starsan and my well water, after a day or two it looks like milk water.  I’m going to try one-step to see how it holds up.  I’m also going to make a 5 gallon batch with starsan and RO water.

I almost always use RO water for my star san. Stays good for months that way. High alkaline water will certainly reduce its effectiveness over the long haul, but is surely good for 12-24 hours or more. My rule of thumb has been “once it turns cloudy, pitch it”. Though the pH rule is more sound.