I just cleaned my above-ground pool cartridge filter. The pleats were covered with a powder blue residue that washed off with the hose, but pooled on the ground — the only blue things I’ve had in the pool are one blue noodle (new this season) and a solar cover that looks like blue bubble wrap, which I am using for the third season in San Antonio, with temps around 100 degrees the past few months. Could the solar blanket be deteriorating?

Question:

I just cleaned my above-ground pool cartridge filter. The pleats were covered with a powder blue residue that washed off with the hose, but pooled on the ground — the only blue things I’ve had in the pool are one blue noodle (new this season) and a solar cover that looks like blue bubble wrap, which I am using for the third season in San Antonio, with temps around 100 degrees the past few months. Could the solar blanket be deteriorating?

Answer:

It could be but that is not likely to be the cause of the blue powder in the fliter. This can be a number of different things usually related to the chemistry of the water and salts or metal salts. For example, copper is typically a blue color and can be reacting to cause the powder you are seeing.