1. High Pressure: If the filter's pressure is too high, it can cause the filter media (sand, cartridge, or DE) to break down and release particles into the pool water. This can result in the appearance of earth in the pool.

2. Incorrect Filter Media: Using the wrong type of filter media for your filter's size or type can also lead to earth in the pool. For example, using too fine of sand in a sand filter can cause it to clog easily and release impurities into the water.

3. Damaged Filter Parts: If any parts of the filter, such as the gaskets, seals, or filter body, are damaged or worn out, it can allow water to bypass the filtration system and carry dirt and debris into the pool.

4. Overload of Debris: If the filter is overloaded with dirt and debris, it may not be able to effectively filter the water and can release trapped particles back into the pool. This can be a problem if the pool is heavily used or experiences a lot of environmental debris, such as leaves and dirt.

5. Improper Maintenance: Not following the recommended maintenance schedule for the pool filter, such as regularly backwashing and replacing filter media, can also lead to the buildup of dirt and debris in the filter and eventually cause earth to be released into the pool water.

Additional factors that could contribute to earth in the pool:

- Soil composition around the pool: Soil that is high in certain minerals like clay or silt can easily be carried into the pool by wind and rain.

- Pool construction: Pools with an artificial rock finish may have a higher tendency for these rocks to shed small pieces into the water, especially if the finish is not properly sealed or maintained.

- Runoff from surrounding areas: During heavy rains, runoff from nearby landscaped areas, driveways, or roads can carry dirt, leaves, and other debris into the pool.