Ethereum fell later in the day on Thursday, reaching down towards the $670 level. I think that the market looks likely to try and find support near the $650 level, and if it cannot find it there, we will see support at the $600 level. Be patient, and add to a position very slowly.
The 0.04 level has offered support in the ETH/BTC pair, but I think we may have a little bit more softness ahead of us. I think you can start to look at the BTC/USD pair for guidance, but quite frankly crypto currencies in general are softening a bit over the last couple of days, so you may want to avoid this pair as it tends to be a bit exaggerated with its moves at times.