So I built a auto water changing system that puts it water right from the tap, my question is about dechlorination, do i need a drip system or can I just splash dechlorinator in the tank once or twice a day?
It depends. If your water supplier uses straight chlorine, you may not need to treat at all. If they use chloramine, you absolutely must treat it. I wouldn't trust adding water treatment chemicals. You need to get a pre filter to remove the chloramine.
If you are only dripping a small percentage a day I doubt if you have anything to worry about. Get a chlorine test kit and check after 24 hours. We use straight chlorine here. I can do a 50% water change and only register .05 PPM afterwards without treatment. Of course they may up what is used due to amount of rainfall and other factors without notice.