I knew my system can handle 250x Exodon Paradoxus (started out with 250) bio load for at least 2 years in 125 gallons before I sold them all (they are at 3.5 inches) WC 20% every week, clean pre-filter mechanical chamber every 2 days, at the time I sold them I hand counted I got 237x Exodon left, they were fed 3x times a day with automated system (bloodworm on weekend for treat) to keep them well fed so they don't turn and salvage each other.