Used Borax and haven't had to backwash my DE filter in 3 months


Gold Supporter
Jun 1, 2018
I added Borax to my pool this summer to act as a pH buffer. I maintain the pool at the recommended levels in the PoolMath calculator for vinyl pools. I noticed that my DE filter pressure has moved barely one unit on the dial since my initial backwash after opening the pool (the gauge works as it goes to 0 with the pump off). The water has been crystal clear and I can read a paper if it was on the bottom of the pool. I haven't had to shock the pool and I stopped using chlorine tablets, just bleach and acid as needed.

I've read that borate acts as an algaecide and I'm wondering if this is the reason for not having to back wash the DE filter.

Thanks to TFP for tips on using Borax, it has saved me time and money on DE and back washing and I don't believe I've seen the water this clear. I live in New Jersey and the pool is open from Memorial Day to 2 weeks in to September.

pH 7.2-7.6
FC 3-4
CC <0.2
TA 80-100
CA 200
CYA 30
Borate 30
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TFP Expert
LifeTime Supporter
Jul 21, 2011
Eastern Ohio
Borax does in fact work to fend off algae, but not likely at the levels used. As Marty said, it’s maintaining the FC/CYA ratio that’s kept the algae away. The borax just helped with your pH.