Iron in water source

[BigDave]

I haven't seen a recent pH or chlorine reading. How are you with chlorine?

Is the water clear but green or opaque green?

[stcohen]

This am pH 7.4, FC >5, water somewhat opaque green.
Have to leave until Fri. am. Will of course keep filter running; backwash and retest on return.

[stcohen]

Returned home. today
FC 5
CC 0.5
pH 7.4
TA 60
Ca hardness 130
CYA 50
Water appears green, not opaque, sediment on bottom, less than when I started this. Placed 1 cal-hypo in each skimmer. Plan to try a vacuum what sediment I can to waste this afternoon and backwash filter. Will adjust pH down after that if necessary.

[BigDave]

Orange sediment on bottom?

[stcohen]

Yes

[BigDave]

Is the filter pressure rising? Are the returns getting weak or is there poor skimmer action? Do you have a 2 speed pump?
It seems clear that the chlorine / raising pH is making the iron come out but it's not settling on the filter as we'd hoped.

[stcohen]

Pressure not really increasing. Returns are strong,1 speed pump (1HP). Had sand in filter changed (200 lb., I think) when I had liner placed
Agree with your assessment, filter does not seem to be capturing much iron.