Taking profits in the Alt coin market is not a bad idea and like you I also like to add any profits to my bitcoin holding. For me the main investment is still bitcoin and I evaluate any other crypto currencies in relation to the change of the bitcoin price. In my opinion alt coins are more risky than bitcoins and should therefore offer us a higher return. To avoid bigger losses it's good to take profits and grow our bitcoin investment. Why not use any new money that you want to invest in cryptos to buy new altcoins? Like that you can rebuild a diversified portfolio while having the majority of your money in bitcoins. The halving next year in bitcoins is going to bring new positive incentives and should push the price higher. As long as you are not switching back to fiat money you are doing nothing wrong.