from slip fitting receiver 19 slip fitting assembly 56 includes a lower cap 48 and an upper cap 52 lower cap 48 has internally threaded passageway 100 one end of a slip fitting 51 is threadedly connected internally to one end of lower cap 48 the other end 58 of slip fitting 51 slidably seats into slip fitting receiver 19 lower cap 48 extends upwardly and includes a generally flat top lip 50 a shoulder 17 is provided on slip fitting 51 upon installation of slip fitting 51 into receiver 19 shoulder 17 of slip fitting assembly 56 rests on upper end 15 during operation of pump 20 top lip 50 supports the filter 22 in a generally parallel relationship to bottom surface 24 of tank 12 accordingly slip fitting assembly 56 is supported in an upright position in slip fitting receiver 19 slip fitting 51 and interior surface 44 are structured such that they fit closely while allowing sliding movement in addition slip fitting 51 length 61 is greater than slip fitting 51 width 63 the combination of the relatively close fit of slip fitting 51 and interior surface 44 and the greater length 61 versus width 63 provide stable support of filter assembly 56 in preferred embodiment slip fitting 51 is cylindrical and interior surface 44 comprises the interior surface of a hollow cylinder upper cap 52 includes grasping member 53 bolt head 54 and externally threaded upper cap body 104 upper cap 52 is threadedly connected internally.