When to backwash DE when filtering a really dirty pool?

[robrinker]

While filling my pool for opening, my well pump started sucking up dirt overnight. Now my pool is a lovely shade of brown.

I have my DE filter going, and we've been bumping about once an hour (the pressure rises 10psi in that time). My manual tells me I need to backwash "when the gauge pressure rises more than 10 psi (.70 Bar) in less than a 24 hour period". Obviously when filtering a really dirty pool, I would imagine this doesn't apply (otherwise I would've backwashed about 10 time now!)

How do I know when I truly need to backwash this thing?

 

[HarryH3]

I backwash mine when the pressure is 8-10 PSI higher than when it was last backwashed. I've noticed that the flow rate drops considerably as the filter backpressure rises.

 

[JasonLion]

You need to backwash when the pressure doesn't go down enough after bumping, say when you are getting less than 4 psi back after bumping. Typically that is much sooner than 10 bumps.

 

[sredish]

If the pool is truly dirty, it's possible that you will need to backwash several times or more in a short period. If the pressure goes up 8 or 10 pounds, then it's telling you the filter is holding enough dirt to slow the flow and it's time to backwash. Some people, when first filtering a really nasty pool will have to backwash 2 or 3 times in 6 or 7 hours.... so read your gauge and watch the flow.

 

[robrinker]

Thanks for the replies!