What could it be?

[guapoflamingo]

We have a three year old gunite pool with a floor system. At three of the jets in the deep end, we're getting dark stains. Two of the floor jets point directly at the main drain, while the other is supposed to rotate. Our water here is hard and has metals, but it's odd that the stains only appear in the deep end jets. Any thoughts as to what it might be? Or any questions that I may not be asking myself?

 

[1poolman1]

We have a three year old gunite pool with a floor system. At three of the jets in the deep end, we're getting dark stains. Two of the floor jets point directly at the main drain, while the other is supposed to rotate. Our water here is hard and has metals, but it's odd that the stains only appear in the deep end jets. Any thoughts as to what it might be? Or any questions that I may not be asking myself?

All the heads in an IFCS are supposed to rotate. With the constant, high velocity, spray in one location, the water has eaten a bit of the concrete "cream" and/or calcium that was on those areas.