APOLOGIES IN ADVANCE FOR THE GROSS PHOTO.
Hi, I noticed that the water at the bottom of my toilet bowl has lessened in volume and has turned brown. This started maybe 5 weeks ago or more. When I flush, the water becomes clear, but if I leave it alone for maybe a few hours, it will have turned brown. I have attached a photo of the water. I also attached a photo of the kind of toilet I have in case that's useful.
Also, the water is always moving back and forth, like tiny gentle waves on a beach. Very strange.
Any ideas what is causing this?
I had been thinking of getting a new toilet bowl / cistern (not because of this problem but simply because I want to upgrade). Will the same problem remain if I put in a new bowl? (I mean could the problem be related to my current toilet or something outside of it).
Thank you

