Pachira Aquatica: too tall/skinny

So I took over care of our office Pachira Aquatica in November and it seems to be doing great. I have no idea its age or previous growth patterns.
Current Conditions: It stands about 3’ above the pot which is 8†across by 10†deep ceramic. It gets just enough water to start seeping out the bottom of the pot every 7-10 days and sits in front of our south-west facing, tinted glass front door which gets late afternoon direct light. It has only 4 trunks, one was cut off about an inch above the soil at some point in its past. The trunks vary in diameter from 3/8†up to 1†thick until they reach about 4 inches tall. At that point they all taper down to about 3/8†and 2 are about 18†tall while the other 2 reach about 3’. All 4 have about a half dozen leaves - none more than 6†from the top. Since I have had it, it has pushed out several new leaves and I have taken 4 established leaves to try and start.
The Problem: I have 2 stakes in the pot holding everything upright because it’s not strong enough to hold up to its height. The trunks were not exactly braided in the beginning and now it’s a bit of a circus getting it to do anything but I’m working on getting it under control.
If anyone has any thoughts or suggestions on how to get it to thicken up before it topples over because it’s too tall I would greatly appreciate it! I just don’t know enough about these to know what’s best for it.
Thanks and happy growing! :-)