ENERGY CAPTURE RATE! strategy of grinding DEC..
Do you notice the Percentage (%) in Dark Energy Crystals? It is the capture rate which tells us how much DEC can we get in every battle we won. With higher Capture Rate, we can get high DEC counts especially combined with higher power collection.
How to grind efficiently? I usually play in Silver I only. I always make sure to have 100% before I rent expensive cards to get power collection. By that, I surely get a higher chance of winning and getting DECs. Then grin up to the lowest % of capture points you want (usually 1 day rent only). Then, replenish the capture rate up to 100% before grinding again (25% replenishment of capture rate per day).
Enjoy! :)