The salt in the water will cause any metal to corrode. They use brass for marine applications for a reason lol.
It's strange to me that it's on the stones, most baddies are anaerobic and thrive in low oxygen environments.
That being said if everything hasn't been thoroughly sanitized there could be any manner of junk hiding in it. I had to try and sterilize a new circulation pump and tubing three times in a week before I finally managed to get it clean enough the infection stayed gone. That was a yellowish sludge building up in the line.
It's strange to me that it's on the stones, most baddies are anaerobic and thrive in low oxygen environments.
That being said if everything hasn't been thoroughly sanitized there could be any manner of junk hiding in it. I had to try and sterilize a new circulation pump and tubing three times in a week before I finally managed to get it clean enough the infection stayed gone. That was a yellowish sludge building up in the line.