Thanks all.
I'm changing about 40 % of the water 4 times a week because I somehow messed up my BBs. Could have been from the Triple Sulfa treatment I used because my Cories had lost their barbells (I finished that treatment 2 weeks ago). Or I could have inadvertently washed too many away when I vigorously rinsed my filter sponges last week, although I used old tank water. In any case, I'm checking my ammonia twice a day and changing 40% as soon as I see a little green with my API master test kit. So the ammonia never gets above .25 ppm.
The angels are still breeding like mad, nothing has effected them. I'm about to give up on Cories as I only have 3 albinos and 1 false-Julii left.
It's a 55 gal BTW, partially planted with a sand base. Occupants are Jack & Diar, the Koi Angelfish, 8 neon tetras, 1 albino Pleco (the kind that stays really small) and the four Cories I mentioned When the tank stops cycling I guess I'll try adding a few more Cories but at an even slower rte of 1 a week.
Open to suggestions.