It was all 3... the levels are good now, and I'm continuing the daily changes and still adding Stability to maintain the BB. I also dramatically reduced feeding for now...
I will have a new sump finished by the end of the week, and it will include a better pre-filter that will be much easier to service on a daily basis. I think the biggest problem was food scraps. Overfeeding, not having a "feed" switch to reduce flow, and lack of prefilter all added up to do this.
When I say I "flushed" the system, it was more of a constant fill, but with manual syphoning out every time it got filled back up. It allowed me to stir up the lava rock and get all the big stuff out.
Also, the new filters on my sourcewater have made a big difference. GH is now 3 and KH is 8.... before, I was using a lot more RO water, and the readings they tested were somehow 0/0...
I'm just happy the Adults are ok...that was a dangerous mistake, and I consider myself lucky to have only lost what I did...
Mike