2-phosphono-1,2,4-butanetricarboxylic acid?


Well-known member
Jun 21, 2010
Washington, DC
I was hoping someone can answer my question. Before I went BBB the pool store told me to put 2 1/2 16 oz. Biogard Scale Inhibitor into my pool. My guess is because my CH was pretty high. My trusty TF-100 measured my CH after I put the scale inhibitor in at 630. The ingredient is 2-phosphono-1,2,4-butanetricarboxylic acid. Does someone know what this is supposed to do? Reduce scaling? I am not about to buy this again I'm just curious.



TFP Expert
LifeTime Supporter
Feb 23, 2008
Denton, TX
From what I was able to gather, it looks to be a metal sequestrant. Sequestrants are used to bind up metals in the water to prevent scaling and staining.