I have a lingering question that I have not found a satisfactory answer to. I have noticed that, depending on where I get my MA from, it can be varying shades of yellow. If I buy the stuff from Leslie's Pool Store, it is often a very bright yellow. The first time I got it, I thought they put a colorant into it for safety purposes. If I buy the refillable HASA stuff from e-Konomy Pools (local Tucson shop), it is a very pale/straw-yellow. If I splurge and waste...um I mean, spend money at Patio Pools, the MA is crystal clear (same is true about MA from Ace Hardware). From my research lab days, we bought reagent-grade HCl and it was also totally clear. All of it is marked as 20 Baume, 31.45% HCl.
I also know that the manufacturing process for making HCl does contain (or should contain) a step for iron removal as Fe-salts are a known contaminant from the manufacturing process. So, does the yellow color of the HCl indicate a poorer quality material with possible iron contamination?