Would not the cesspool pump truck operator know that he was sucking in pea gravel in a short pool?I understand your reasoning. Respectfully said ,it is my reasoning to put pea gravel is it should still drain for a while then clog. At that point you get pumped ( they dont pump as much as they say because they pay to get rid of water) .They aerate and you have drainage after shelling out $700.That works till it dont work and you get pumped and aerated maybe 2more times . Cememt would be found quick and i always enjoy giving a long term focking when needed