Should I backwash my DE filter after shocking?

[Kelleyaynn]

I'm in the midst of shocking my pool for mustard algae. The pressure on my DE pump has not risen at all, and the water never got cloudy, even after brushing. Should I backwash anyway, to try and get rid of as many algae spores and such as possible?

Thanks.

Kelley

 

[Thinkly]

I would not. My assumption is that the mustard algae will be killed regardless of whether it is in the filter or the pool. I think the only time to backwash a DE filter is when the pressure goes over the manufacturer's specified level. On my DE filter, even when I backwash there is still a LOT of DE left in the filter. Backwashing does not leave you with a crystal clear set of grids, it will likely still be pretty caked with DE, so even if you backwash you will have a LOT of old DE left in there.

 

[Kelleyaynn]

Thanks, you reply makes sense to me.

Kelley

 

[jblizzle]

I do not know what the "manufacturer's specified level" is for backwashing ... how can they give a number without knowing your pump, plumbing and head loss?

Just wanted to point out that we recommend backwashing when the pressure goes up 20-25% of the clean pressure reading. (The old 10psi pressure raise is not a good rule of thumb).