Quote Originally Posted by PoolDoc View Post
Darn it. I was trying to pick things that had definite ingredients, and would ship quickly. But apparently this warm winter and spring has played havoc on some inventories. Anyhow here's an alternative:
Jacks Magic The Pink Stuff 1qt (60% HEDP)
It is 60%, instead of 20% (GOOD!), and does not ship directly from Amazon (BAD!), but it should ship faster than the *new* Amazon shipping schedule.

The problem with many of the other products is that the are things like sodium citrate (not chlorine compatible!) or EDTA (barely chlorine compatible). There are more products out there with HEDP, but it's hard to identify them.
If it's not inappropriate (Ben, please delete this if so), I've always received a good deal and great service from poolgeek.com for Jack's Magic products and the polyquat I use.

Quote Originally Posted by PoolDoc View Post
Using HEDP regularly increases chlorine demand slightly, but the phosphonates break down to plain old phosphates, which encourage algae.
When I started using the product, I asked about the phosphate issue and was told it didn't increase "orthophosphates" which is the form of phosphates that encourages algae growth. Do I understand you correctly that this is false? Does it matter if I use borax in my pool (50ppm)?