I'm so sorry this is happening to you again, but it sounds like it's not the same thing as last time, thankfully...I seem to remember looking up what a bowl that came with a big floor-perch came with, if that was you I looked it up for, I think it was...I think the bowl was listed as being made from "sandstone" on the manufacturer's website/catalog when I looked it up (and if I recall they didn't make it easy to find the answer to that question either, like it was a secret what that bowl was made of)...
Usually when it's heavy-metal toxicity they get it from chewing on cage bars or a commercially-sold toy with metal parts....That's probably 75% of the cases, the rest are due to the little jerks finding something in the house to chew on that contains metal...And a lot of the time we wouldn't even know that certain items in our homes actually contain any metal at all...
I watched an episode of "Dr. K's Exotic Animal ER" once where a poor man had lost his dog a month prior due to old age, then he had lost his female Cockatiel who was only 7 or 8 years old suddenly 2 weeks prior after trying to save her at their hospital, and during this episode his only remaining pet, his male Cockatiel who was the mate to the female he had just lost to a mystery out of nowhere suddenly became obviously very, very sick...He rushed him in to Dr. T, the other Vet there, and they did an x-ray and found obvious metal flakes all throughout his GI Tract...So they started Chelation-Therapy while he tried to figure out what in his house they had been chewing on and that had most-likely also killed his female Cockatiel 2 weeks prior...He came back to the hospital with this antique statue of a goat that was outwardly made out of wood, but it was obvious that the birds often chewed on it because it had beak marks all over it and he knew they both had chewed on it all the time, but didn't think it was a problem because it was a wooden statue...So they didn't think the statue was the culprit, but just because both birds had been chewing on it for years, they decided to actually x-ray the wooded goat statue...And low and behold this wooden goat statue was full of material that glowed brightly on the x-ray...So the wooden statue actually wasn't ALL wood, it was made of some type of composite-wood that contained heavy metals...And the male Cockatiel died of the metal poisoning too...I remember feeling so sorry for this poor man who had lost his entire family in a month, he kept saying how quiet his house was...
Soooo, the point to my rambling story is that anything and everything can contain different metals, even if they are made of wood, plastic, ceramics (especially, as many types of processed clays contain metals, as well as alot of glazes), and also anything painted can contain heavy metal, as they add all kinds of stuff to paints, stains, glazes, etc. So basically what I learned from that episode of "Dr. K's" was that if you think your bird might be suffering from metal toxicity/poisoning, instead of looking for things that are metal around the house or in their cage that could be the cause, you need to look for ANYTHING and EVERYTHING that your bird may have or obviously does chew on and have it checked-out...If it glows on an x-ray, it contains metal...
I hope that isn't your issue here with Fang, it doesn't sound like it honestly, usually when they are suffering from heavy-metal poisoning they don't get at all better over time without treatment, they just continue to get gradually more and more sick...So positive-energy your way and to Fang...And keep us posted!
