I'm in the slow process of doing an upgrade. Tbh, I was reluctant to buy the tank + cabinet, it wasn't what I wanted being black and tank showing signs of age. However, the price was good and when finished I'll have 480ltrs instead of 300ltrs. I've now finished the cabinet rebuild (oak). Have the new return pump, skimmer, dosers, atu, light have re-done tank background and wier acrylics. Filled tank once in situ to check both stability of cabinet and that it didn't burst lol, been moved around a lot. Have a "haze" on the inside of the glass that's proving hard to shift. Calcium deposits? Is it safe to half fill tank again with tap water and citric acid mix, wash everything down the drain and fill a few times to get rid of any traces? Don't worry I'm not on a water meter!!