I won't make that mistake again, but the pump had a sponge in it. It
only took me 5 months to find that (in all it's gelatinous glory) from
my system. I kept wondering why (WHY?) do I have all this diatom growth
and lately red slim growing. And, why are my fish starting to gasp?

Doh! No water flow from the sump. That's it.

--Kurt