Added DE - when to backwash?

[LynnDi]

I just added DE to my sand filter for the first time yesterday. From what I read, you should watch the psi over the first 24 hours.
My psi only went up by about 3, but the water pressure coming out of the return decreased dramatically. I panicked and backwashed immediately. Should I have left it alone and waited for the pressure to go up more? Up by 10? Appreciate any advice. Thanks!

 

[wireform]

25% increase from known clean pressure. Make sure the gauge isn't broken and rests at "0" when pump is off.

 

[LynnDi]

25% of what?
If pressure is 0 when filter is off, and pressure is at 10 when filter is on, then adding DE brings it to 11 - is it 25% of 10?
Meaning if it raises to 12.5, I should backwash?

 

[LynnDi]

25% increase from known clean pressure. Make sure the gauge isn't broken and rests at "0" when pump is off.

Also, thank you so much for your response!!