Bummer. More questions:
1) did you retest? If so, did you register any FC/CC?
2) can you see the bottom? If so, is there any gunk you can clean out? If not, use your leaf Rake and see if you can dig up any organics in there.
3) did you add cya yet? If not, don't.
4) how is your supply of 0871 and powder for testing? You will need a good supply for your next steps.