Ive been to two pool and all over net i understand the replacement for size b for unicel is c 5315 however having tough time finding it found it once place got nervous cause said for 15 ft rd. Mine is 22x52. I found a pLeactco dont know if pleatco is as good if anyone has a website to get a unicel to replace my size b model # 59905 please fwd the link. Or chime in on the pleatco. Ive read all the strings on it the c5315 seems right unicel replacement but y said 15 ft dont know. Thanks guys