Pool Top-up Pipework

Hello I hope you can help me understand the pipework for topping up the pool. There is a big header tank in the plant room which supplies fresh water to the pool. The feed from the header tank splits into two.  One split passes through 2 ball valves labelled 'manual top up' and 'break tank isolation' before heading off toward the pool. This split also has a loop in it with what looks like an automatic valve which is unlabelled.  The other split passes through an unlabelled ball valve and then also heads off towards the pool. I was hoping you could help me understand why there are the two splits (does one go to the pool tank and the other to the balance tank perhaps?). Also, I would like to understand why one split has the loop with what I think is an automatic valve in. Thank you Ben