Question
There is an area of my lawn that has yellowed or turned light green.  I am certain it is from backwash water from our pool.  We do not backwash often, but the pool water seems to be affecting the grass. If it is form clorine in the water, can it be countered with a lime fertilizer?  I am afraid the area affected may die if we do not treat it.  

Answer
Hi Vince,

>>"...water from our pool...?"

Lime or fertilizer will not fix the chemical damage.

There is no remedy for the effects of pool chlorine on the green vegetation. Non-toxic 'physiologic' induced yellowing of turf-grasses can sometimes be remedied by adding iron to the top-soil,...but if it is indeed caused by the pool chemicals, adding minerals will not help.

The chlorinous chemical will oxidize the green-plant pigment causing the yellowing, and the grass suffers from a toxic shock syndrome.   Time and watering will eventually dissipate the toxic residue in the top-soil, but the grass will probably die depending upon the dose and grass-type.

You can speed-up the recovery process by excavating away the affected soil and replacing it with some commercial bagged top-soil or, better still, potting-soil from the local garden center.  Adding humus and compost is also recommend to heal the buffering balances in the root-zone.

The turf-grass can be re-seeded or sodded to fill in again. If it is a Bermuda grass lawn, the surrounding grass will eventually fill-in or you can sprig the bare area to speed-up the coverage.  Cool-climate grasses (Fescue, etc.) will have to be re-seeded in Sept-Oct.

__ JHG