After inspecting customer’s toilet, it was determined that the reason for the slow fill after flush was because the old fill valve had a lot debris lodged inside of it. Replaced it with new fill valve and toilet is filling back to normal. Was not able to reinstall customer’s water softener because could not find a replacement part for the O ring at any supplier. Customer will need to order it online and once they have the part, we can return to reinstalling water softener.