Most septic tanks have an effluent filter that needs to be cleaned periodically. The filter is located in the solids tank which should be the one closest to the house. See the links below for the parts and tools I used:
Septic Lid Removal Tool:
https://amzn.to/3Oe38oZ (affiliate*)
Septic Effluent Filter:
https://amzn.to/3umTN5I (affiliate*)
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