Full picture of the system
Pros
- Equally splits any amount of fluid to 4 tanks evenly.
- Even with unbalanced drain, it will try balance tanks. (Example if bottom two tanks are empty, top two tanks will stop from filling until rest of the tanks catch up).
- If you copy the power switch near your oil pumps, it can turn pumps off when tanks are full. (Useful when you use modules and beacons on oil fields saves ton of energy).
- You can use it anywhere. Atm. I only use when loading tanker trains.
- Works on any fluid.
- It's pretty slow.
Showing just what you need change to make it faster. You only need change it to one pump and copy it to others.
How it works.
Each of tank signal is changed to A, B, C and D. The < combinator compares value between all the tanks (A<B, A<C, A<D), sending signal 1 if true. If all are true, pump will start pumping until it's changed. Other combinators are pretty much fixing errors. Combinator = is checking if there is evenly amount of fluid it will pump more fluid to make < combinator working again.
(I realised that this isn't needed. I removed it from blueprint, since if all are empty, = ones will give the signals, if one or more is empty < one will give signals as well to power the pump.)
The one arithmetic combinator is changing all signals to signal 1 to give signal to switch. Switch will be on until all tanks are full. This can be used to turn power off from your energy beast module/beacon oil fields. Lamps just indicates how full tanks are for fast visual show how full tanks are each lamp goes on on 2,5k difference.
Each letter is amount of fluid in each tank. Showing how evenly it fills the tanks.
Demonstrating with water how evenly tanks gets filled.
And lastly blueprint string, this is spaced directly to train rail tankers so just make a station and paste this next to tankers. I recommend train tanker and flow control mods with this:
I found error with the last lamp, change value from 10,000 to 9,999.
Blueprint
I would hear some feedback and how useful you find this is. Thank you 
