Some related points:
-- my BBXB also has only been under the same LED lighting/schedule as the GHXB, but she in fact is even deeper gold than the GHXB (which I mostly attribute to her being in a much darker tank with black bottom and dark purple background). She's crazy colorful, esp. for her age, I personally wouldn't chance charring that with tanning. (of course I'm not sure she is really a she
)
-- in hindsight I have to say that actually the tanning regimen you propose above most would call 'soft tanning', not hard (e.g. 24/7 and lights with even more UVA/UVB, like Arcadias, which are popular with Red Aro tanners). As such, your fish might be less susceptible to the negative consequences I mention above, only time would tell, but again personally I don't think it's necessary and prefer a more patient, longer-term approach. I shouldn't have come across as overly critical of your approach, and either way we can likely learn something from the results.
-- I would also agree with the notion that our Arowana need some UVA/UVB light for best health (in fact tbh I have been wondering if this is a possible weakness with my current LED lights). But if I ever did add some I would only use them occasionally and probably only for a few hours at a time, and not under a 12/7 (let alone 24/7) full tanning regimen -- partly because I wouldn't want to risk charring, possible DE, etc. but also very importantly because I personally don't think the fish are so comfortable with the process, but that's just my opinion.
-- if you are going to use tanning lights, I've seen many suggest to start with a shorter schedule (e.g. a few hours a day) for a week or so, rather jump directly into a 12 or 24-hr format, which makes sense insofar as stressing the fish less, so maybe something to consider.
-- as you're planning to run your tanning light(s) in a community tank, it'll be interesting to see whether or not there are any noticeable coloration changes with the other fish, plz let us know on this point too.
