Here is a picture showing the size of above-ground growth to the size of the pot currently being used.

Hey, Kevin, you found house plants forum! (Asked about in name-that-plant, diagnosed with sunburn.) Hope you don't mind, I'm pasting the info you added in the other discussion, in reply to my question about if it had been repotted:

Gah, bummer about the leaves, I'd tried
to carefully craft a foliage that was equally distributed around it by
turning it occasionally to get light exposure on different sides :/ ah
well, I can do that again with the new growth. However, it has been 1.5
- 2 yrs since repotting. Should I probably change the soil, then?
Also, do you think the pot is still an appropriate size or should I also
try to get a new, larger pot for it?

You were doing a great job with the symmetry!

I'll leave the giving of further advice to those who have a great looking Pachira (vs. none at all, like me.) Best vibes!

These 2 posts should have helpful general info in which you might find possible areas to improve, and about repotting in general:

http://forums2.gardenweb.com/discussions/1490818/good-growing-practices-an-overview-for

http://forums2.gardenweb.com/discussions/1497307/ukeeping-u-them-looking-good

Indeed! (re: finding this forum, not only a more appropriate forum for my question but doubtless useful for future questions) Thanks for following my plight and trying to aid in my being assisted in this, as well as thanks for the compliment regarding the symmetry :) I only wish you could have seen it a mere week or so ago when it was completely healthy and the foliage was full and robust, when that symmetry really declared itself :/

Also, thanks for the additional links, I'll take a look and see if they can be of any help!

Interesting regarding the acclimatizing of the leaves to a certain degree of sun/heat; that makes sense but was previously unaware, and indeed had kept it under gentle filtered light previously. Thanks for your help and the tip regarding repotting.

On a partially-related note: your Pachira, shown, looks lovely (b'.')b and I look forward to the next few week or so as, I would hope and expect, the new foliage on mine begins to regrow. My little guy started as a little ~8" fella, and has since grown to prob about ~22-24", and I continue to look forward to the day when he'll reach 4-5' (unless I misunderstand something) and will have yet retained, by my continued close attention, his beautifully braided trunk at that size :D

Do you think that if it has developed a reasonable amount of new foliage across the next month or two, since I live in CA and the weather will remain warm here till mid-to-late September (if not longer), that it would perhaps be safe to replant it (same pot) with new soil before next June? I wonder if it wouldn't be better to add new soil asap what with it having used the same soil for 2 years now, yet don't want to risk it's health by shocking it a second time in too quick of succession. I think I could probably judge its health well enough to decide, but I welcome your (or others') opinion in that.

In my honest opinion, ( for what it's worth) I would wait until next June to repot. If you repot now you will risk losing your plant because of the damage it has right now. Usually it is better to wait until they fully recover because the damage on top of possible repotting shock may make things worse for it. Mine does well in bright shade and I only water it about once every couple of weeks. When I first got mine last October, it only had a few leaves. Now, It has baby leaves all over it and it's nice and bushy.

Your watering schedules seems to fit with mine. I think I started watering it a little more frequently recently for having it moved it to the living room where I was suddenly spending more of my time (thus noticing it more) and thinking that perhaps the frequent AC and fans blowing might be drying it out more, so I just went "herpderp, well the soil's dry to the touch, guess I can/should water it more often" but even if that were true, and it probably wasn't, then I still shouldn't have probably watered it as frequently as I did. Because as with you, before I was only doing so every few weeks.

But in more direct response to your take on the matter: so you don't think severe nutrient deficiency would be a mortal issue in the meantime (till next June)? I wondered about repotting earlier rather than later out of fear that the recent ill-health might potentially have been caused by less nutrients and simply want to minimize risk of losing the lil feller.

If it was my plant I would return it to its original growing spot and watering schedule before repotting. By doing that you put it back in its happy place and it might be able to grow new leaves better. After it has come out of the damage and grown new leaves then you can repot if you still think it needs to be repotted. Sometimes when you move a happy plant they go through a phase that sometimes they don't grow out of unless they are moved back to their happy place. As for the nutrients, I don't think that is an issue right now. I am no expert but it looks to me like it has suffered from overwatering and sunburn. That is not a nutrient issue. If the plant was fine until this happened then, no I don't think there is a severe nutrient deficiency. If you do decide to repot it now, the only thing I think might help it is drying the roots some and making sure your potting medium is also dry. Then put it back in its original spot and resume the original watering schedule. I hope with everyone's input you can find out what will work best for you. Keep us updated and I hope your plant pulls through for you. Mine is one of my favorites.

Wait until next June, or late May. Trust me, I've done out of season re-pots, and the plant will potentially sulk for months! When you do re-pot, you'll want a porous mix, moistened, and ready to go as soon as you get the old mix off the roots. Do not let the roots dry out, not even for a minute. Then, replace the mix, and water the medium well.

You should fertilize your plant with a good liquid fertilizer, once it has initiated some new leaves. Indoors, give it as much light as you can.

My Pachira was grown from a single leaf, which is why it is a single trunk. I have pruned it many times. It becomes too tall, and acts like a windsail!

Josh