So I have a 220 mixed reef that I've noticed has a hazy film on the inside of the glass. If you look straight on or from above it's not that noticeable (except to me) From below it's obvious. It's a standard All-Glass aquarium not low iron. It's been set up for six years and have only had the haze for last several months. I've tried razor and magic eraser feverishly with no luck. I don't think the haze is "in" the glass as there are "clearer" continuous lines/paths about 1mm wide throughout the glass surface. My guess is collonista snails that populate the glass at night. The two things that seem to coincide with the haze is elevated calcium level and higher ph. I replaced my 2 part with All For Reef about 8 months ago. I based the original dosing amount on ALK. I tested myself daily and had two ICP tests done for the first month to zero in on my range which ended up being 7.5 dKH and 439ppm Calcium. I've since increased timer when needed based on dKH readings. I'll admit I only took one calcium test in last few months but I test dKH weekly and maintain in mid 7s constantly. I maintain lower dKH as I run somewhat low nutrients <5 N03 and <.03 P04. Occasionaly they bottom out if I slack on feeding. I feed three times a day. So I notice on my bathroom shower glass panels that I have a similar haze which I'm having a hard time completely removing. Even with commercial products and vinegar. It got me thinking that maybe the aquarium haze is hard to remove calcium build up. I took a calcium reading and it was 550ppm. I took a second reading and confirmed. I just sent out an ICP test and am awaiting results. I have also noticed that over the last several months, my ph has been consistently 8.1-8.25. It used to run 7.8-8.15. I have no idea really why the increase but was happy. I confirmed my Apex reading with a hand held ph meter. And lastly, the right side of the glass is worse than the left side. I know there is more flow on the right side of the tank near the glass. I'm gonna stop the AFR and just add baking soda for ALK to get calcium back in range for now. Then I'll test calcium weekly with alk to see if it starts to out pace the ALK again. Curious if anyone has any thoughts on this.