DIDYSIS WE NEED YOUR SETUP IN HERE!
Step by step with pics
especially the float switch and pump. I am doing that for the two new tanks I just bought.
Step by step with pics

Great thread. I have been pretty busy lately and wanting something to help give me more free time and improve my water params. Just after some advice from the experts here.
My tank has an auto top up unit (Tunze). The top up resivour is about 220L/60G.
My plan for the auto drip system is to use a spare small pump on a timer to periodically pump out water from the sump, thus maximizing the old water that gets removed. Also this way I can control the flow pretty easily.
The auto top up will refill the sump, I will use a float valve in the top up resivour to keep it at least 40% full, and have it set up to collect rain water.
My town water only has chlorine, I hear people use filters and some don't bother if they only have chlorine. I am planning to change about 1/2 to 3/4 of the resivour a day so the water will do a lot of sitting around, not enough time to dissipate all the chlorine though. Would I be able to get away with no chorine filter? Would leaving a bag of carbon in the bucket have any effect in removing chlorine? Like leaving it up against/on top of the top up pump.
If the float fails the sump won't overflow as there is a hole/hose near the top of the sump to drain when water gets too high.
Look into an Aqualift pump to remove the water from your sump. They look like a small air pump but they are designed to suck water - hooking it up is as simple as plugging it into your timer, dropping a piece of 1/4" tubing into your sump, and routing the other 1/4" tube to your drain.
Whatever pump you use, be sure to leave an air-gap to avoid syphoning if your drain is lower than the water level of your sump.
As far as the Chlorine, I can't really say - I've been on well-water for the past 25 years.
Will look into them pumps, there will be no issues with a syphon with my sump drains/hoses.
Does anyone know if Carbon will have any affect in removing chlorine? And how much of an affect?
I use the aqua lifter pumps in my overflows as well, you cannot do it without one or you will have a failure in breaking syphon in no time. As for as chlorine remove hit up www.thefilterguys.biz and email Jim. He can point you to the right filter to use for your water. Great guy and I have been doing business with them for years. I highly recommend them.