That's interesting that you know this depression is going to happen. How much money have you placed on this certainty? There's a few different ways you can short the Chinese economy. You'd be crazy not to if this is as sure a thing as you say.
Don't forget, the market can stay irrational longer than you can stay solvent
(Background for non-investors: leveraged ETFs are intended to replicate intraday performance, and a long-term buy-and-hold strategy is always expected to trend toward 0)
(For one thing, ETFs like to buy and sell whole sectors of the market: if Volkswagen has a problem, they sell Toyota. This strikes me as a good way to lose your money -- while not really understanding what's going on.)
Here are some examples of levered ETFs... sorry, it seems most web UIs are interactive and actively resist linking to a customized chart. I'll link to the benchmark. You'll need to click "Compare" and enter the two leveraged ETFs, be sure to check the "Display as a Percent Change" option, and then mess with the duration (from 1D through 5Y is illustrative). You can see that daily or short-term returns are inverted relative to each other, but long-term returns (6 months or more) are net negative across every pair of ETFs.
Crude oil: UWTI is 3x, DWTI is 3x inverse. USO is a proxy for the benchmark. http://www.barchart.com/interactive_charts/etf/USO
Small caps (e.g. Russel 2000): TZA is 3x, TNA is 3x inverse. IWM is a proxy for the benchmark. http://www.barchart.com/interactive_charts/etf/IWM
Financials: FAS is 3x, FAZ is 3x inverse. XLF is a proxy for the benchmark. http://www.barchart.com/interactive_charts/etf/XLF
Bottom line: for buy-and-hold investors, leveraged ETFs are always a trap.