Oxyclean Grit

I’m stumped.  Last month I did a clean and soak in the tub with Oxyclean, and it actually sat for days!  I had no issues at all.  Last night, I did another clean and soak, and this afternoon, they’re all gritty.  I’ve learned that Oxy has a tendency with hard water to do this, but I’m really scratching my head as to why this didn’t happen before.

Would the days-long soak cause the grit to go away???  I don’t get it why this time vs. last time.

I need to bottle tomorrow, and I’m going to drain, refill and add Starsan.  Any suggestions for HOW much Starsan to had to a bathtub full???  8oz?

The bathtub? :o I would stick to the recommended ratio of Starsan to water.

I’m a bit mystified. Are you sanitizing bottles? If so, why not just use a half gallon of water in a bucket with 3 ml of starsan, and then reuse the solution? A tub full sounds profligate.

I’ve seen it with hard water. Do you have a water conditioner? Maybe it was due for a regeneration cycle the second time?