Should pool filters be cleaned before or after the first chemical treatment?

[Zara Nazir]

When opening a pool for the season, there are several maintenance steps happening at once—cleaning filters, adjusting water chemistry, and starting circulation.
Is it better to clean or backwash the filter before adding opening chemicals, or should the chemicals circulate first before cleaning the filter system?

 

[Krzysztof Petrov]

I usually clean the filter first before the first chemical treatment, at least a backwash/rinse and clearing the skimmer and pump basket, so flow is strong and the chemicals distribute evenly. If the water is really bad (green or super cloudy), I’ll sometimes get sanitizer in first with the pump running to start knocking organics down, then plan on cleaning the filter again within hours to a day or two because pressure tends to climb fast once the filter starts catching all that debris.