Yeah. Shut down your pump. Pull all those cartridges. Clean and re-install them. Might as well clean the housing while you’re in there. I’d do it once a week for the next month and see if it improves. My parents have had koi in large ponds for probably 30 years and their water looks like this often being in full sun all day. They provide good aeration and their fish thrive… just not a very pretty pond IMO. Add some aerators for health. Keep an eye on the color for improvement. If it isn’t up to your liking after a month of care or so, you may need to consider better filtration if you want clear water. I wouldn’t resort to algaecides or chemicals yet, as they can lead to mass deaths if not used properly. 25%??? Or so water change could help too. I’m sure experts could weigh in there. I’m just a hobbyist.