Here is a little more about what happened with the glass.
The tanks sat for a few months at work with no circulation. The place is susceptible to power outages and I finally gave up. When it was brought home, it was thoroughly cleaned before installing but the lighting in the room was not in place yet. When the tank was initially filled it looked great. After the new light rack with the Radions was installed, it seemed like there was a film inside the tank. If you have ever seen the windshield of a car that is smoked in, it sort of resembled that. I thought it was an oily film left from something that had been done in the house during our demolition, painting, or renos of the family room. I tried cleaning with algae scrapers but no matter what I did, I could not scrape the glass clean. I ended up draining the tank to see what was wrong and try a different approach.
I tried every idea I could come across from RC and the internet in general. I used muriatic acid, CLR, power polishers, steel wool, headlight cleaner etc. etc. Nothing I tried would remove the etching. I talked to a number of glass people from various companies and the basic consensus was that it was damaged beyond repair and I would need to replace it. I had almost accepted the fate and was on the verge of replacing the tank (but was on the fence about the size). I wanted to change the dimensions but I really did not want to tear apart my new hard work. Total dilemma.
After more searching on the internet I called another local glass repair guy. He agreed to come out and take a look. On first inspection, he thought he could fix it fairly easily. He started by using the typical polisher with cerium oxide but was not having any luck and gave up. He opted to try this special polisher that uses a suction cup and a water sprayer attached to the glass.It was a long slow process. This tool was great and actually removed the haze... Sort of. He polished the entire front of the tank. I should note that the sides of the tank were fine. They are a different glass and for some reason not damaged. I suspect the front glass was a poorer quality.
After he polished the tank it was great except for one thing. The tool does not allow you to get to the edge. I was stuck with about a 1-1/2 inch strip down the sides. It actually stood out worse then before... Plus I now had a $400 bill for the four hours of labour.
Here is a picture after the polish.
I filled the tank to see what it looked like (hoping it would not be so noticeable).
Here is what it looked like with water (before I got through with my efforts).
Still not happy about ordering a new tank and all the work I gave it one more valiant attempt. I spent about 5 hours with 3000 grit wet sandpaper and a angle grinder with the polishing pads I bought to make the bar counter top. I did not use anything rougher then about 1500 grit and used it up to the 3000 grit and final buff attachment. It was a little nerve racking as I was concerned about the arbor wheel of the grinder contacting the glass and shattering it. It is not quite as clear as the area he did when the tank is empty. At this point I believed I was more or less just going to try and feather in the difference so it was not noticeable. After all the efforts and what looked like the best I could do, I decided to fill it with water again. When I filled the tank, the entire strip actually disappeared. You cannot even see any evidence of water damage anywhere!
In the end I saved the tank and it looks great.If you have a big expensive tank that is damaged, don't give up. There are ways that they can be fixed. Some of these big glass tanks in the 3 - 7k range can and should be fixed. Spread the money on something else!
