unfortunately, the new impeller's shaft was NOT removable unlike the old impellers.. thus, i had no choice but to break the new pump's impellers ceramic shaft. i also replaced the ceramic shaft for the new impeller from the old one... Wish Aquabee could've sold only the "skimmer-type" impeller... anyways.. the job is done and the skimmer runs fine now... maybe I'll operate on the old pump just to find out what causes the intermittent operation...