Gary Majchrzak
Team RC
quote from Randy winter of 2009-2010
fast forward to present- winter of 2010-2011
has anything changed with the formulation of Prestone Driveway Heat?
For the benefit of those newer around here...
I carefully tested Dowflake for impurities several years ago, and it was as clean as the most popular hobby supplements. In fact, it EXACTLY was the same as several brands in impurity profile and concentration.
Turns out that bulk chemicals are made on a huge scale, and many times higher grades just reflect more testing criteria for release, but not that the other grades are any worse.
After talking to some folks in the industry, we determined that Peladow was essentially partly dehydrated Dowflake, and also that at the time Prestone Driveway heat was repackaged Peladow. So we figured it would be similarly useful, but with a warning to start slowly and watch the tank for any adverse events.
I cannot be certain that that is still the case, but many people have used and continue to use Prestone Driveway Heat OK.
The DIY two part recipe that I came up (below) with was based on Dowflake initially, but now is sold by other folks like Bulk Reef using slightly different ingredients based on what is readily available.
The biggest concern for a while was that Dow stopped removing bromide from all grades (even food grades) and that was a concern. However, it seems not have not caused any trouble for anyone that I can tell.
Beyond that, Dow has sold or is selling its calcium chloride business. I expect the Dowflake name will go with it, but going forward, it may be sold under other names.
These may help:
Purity of Calcium Chloride
http://www.advancedaquarist.com/issues/mar2004/chem.htm
An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System
http://reefkeeping.com/issues/2006-02/rhf/index.php
Bromide in Dowflake may OK w/water changes
http://www.reefcentral.com/forums/showthread.php?t=1527547
fast forward to present- winter of 2010-2011
has anything changed with the formulation of Prestone Driveway Heat?
