We must correct the cause, ...

We must correct the cause, not the consequence

Hi, Your solution is good, but expensive at first sight in time. I give some explanation: the water contents in the reservoir is acid in reaction to a first element.

To correct the consequence will be expensive because the water is going to eat away your whole piping and a part of the tank.
If it is about a superficial accumulator of water, it is can be because the ground is some sand?
Either they are maybe concrete tiles ?
In this case, it would be necessary better isolated and retained the water by a cover in PEHD (plactic high density).
You can contact me to have better one analyze of the situation.