Hey guys, I just recently (about 3 weeks ago) became the owner of a 2002 Master Spa LS1050 (large 8'x10' spa that hold 620 gallons) that is in great condition mechanically (only a few missing jet inserts, diverters/waterfalls all work well, two of the main pumps replaced a year or so ago), good condition electrically (heater works great, pumps all work great, lighting was non-functional and it has the fiber-optic option, the light lens itself needed to be replaced as it had the familiar cracked surround), and exterior wise the plastic side paneling was good, just needed to have the panels realigned and cleaned up. Interior wise the acrylic is in excellent shape, the weir and plastic filter cover are faded, but intact, and the pillows all need to be replaced. The fiber-optic lenses, ie the small plastic light points are all brown colored (originally they are clear plastic) and the acrylic has a light tan tinge to it inside the tub. The outer part of the tub (where water never sits) is perfectly white, for reference.
Once I got it home and setup, I cleaned it out real well, replaced 4 of the 6 pillows so far, replaced all the missing/non-functional jet inserts, cleaned the filters twice, replaced the plastic lens for the main light, removed the fiber-optic unit and got it functioning with a new transformer and light bulb and cleaning up the lenses/color wheel, put a new cover on the spa (previous one was water-logged), replaced the ozonator with a Del Spa APG unit, have a liquid gas mixer on the way and in general have been enjoying the spa quite a bit.
My big question comes in regards with how to deal with the staining that exists. It is not bad in the tub acrylic itself, but I do notice it and it bugs me, but the staining on the fiber-optic plastics is the main issue I want to resolve. I assume they are rust stains from some point in the tubs past, but is there any way to make those plastics clear again?
I have read on here about addid ascorbic acid to pools to get rid of rust stains, and I have read about draining the spa and using direct muriatic acid to the rust-stained parts, but honestly I really don't want to screw the spa up in doing something to remove the staining.
What would be the best way of dealing with this? It would be great if AA would work and remove all the staining throughout by just adding it to the spa water (would be easier to deal with in regards to cleanup too as I could just drain and refill the spa when I am done, but honestly even draining and using muriatic acid directly isn't that big a deal either. I just don't want to spend a bunch of time and money grasping at straws in trying to deal with this cleanup. I am just about the only one to notice the light-tan tinge to the acrylic so that is much less of a concern than the clear-plastic fiber-optics. Considering how the tub is foamed internally, replacing all 32 of the fiber-optic lenses is really a major undertaking and the increased risk of leaks form doing it is a no-go as a possible fix.
Any and all input would be greatly appreciated.