How do you get rid of dry spots on Acrylic?

[Northwest_Scapes_]

So I'm cleaning out an old 50g Acrylic that I'm going to use, I used 800 and 1500 Wetdry sand paper (Home Depot didn't have any 1000 or 2000) since there were a ton of scratches and polished it off with Novus 1, 2 , and 3. It worked out really well, about 95% of the scratches are gone, but now I have these wipe marks which I believe might be from water I test filled the tank with, does anyone know how to get rid of them?

 

[xxkenny90xx]

Looks like you need to go to a higher grit sandpaper.

Maybe they aren't so bad though, are they even noticeable when wet?

 

[snorklr]

you can find finer grit paper at auto body/ auto paint supply shops...some Oreilly auto part stores have paint departments in them too...or you could buy one of the 3M kits for polishing faded auto headlights...comes with a foam buffing wheel for a drill and a variety of grit pads and a little polishing compound...idk if you're using the novus by hand that would be pretty hard to do....it probably looked clear when you were done cause the novus stuff was wet...once you filled it with water you washed off the film of novus and exposed the scratches

 

[Northwest_Scapes_]

Hey everyone, I ordered some 1,000 / 2,000 / 2,500 sand paper and actually did the polishing routine correctly this time, and its about 95% scratch and smudge free! Theres still some scratches on the bottom, but those will be covered with sand. And the smudges are basically non-existent when the tank is filled.

 

[Pistondog]

Polishing compound would finish it, but as you said may be invisible underwater.

 

[theatrus]

Hey everyone, I ordered some 1,000 / 2,000 / 2,500 sand paper and actually did the polishing routine correctly this time, and its about 95% scratch and smudge free! Theres still some scratches on the bottom, but those will be covered with sand. And the smudges are basically non-existent when the tank is filled.

I've always had a very hard time polishing anything near the edges or border, so its a win in my book.

From experience, even if its not visible in a clean state, a roughened texture of acrylic can be a great surface for GHA or other nuisance algaes to cling to.