In that case, you understand the market very well but never undermine the huge volatility of altcoins. Most times, the volatility can take you unaware and before you can realize it, you have already been liquidated. So, even if you research and catch up with good altcoins for short term investment, never hold for too long when market is crashing. Always have target for your expected profit and if possible you can even set a selling target which will execute once price reach there. It very possible that even while Bitcoin is surging, so many altcoins will be crashing.