Blue-Green Scratches/Stains at Bottom of Toto Drake, sodium bisulfate

[trg12]

I have a Toto Drake toilet, and I've noticed a green or dark blue/black area at the bottom interior. It's not mold and won't come off. I contacted Toto's customer service, who suggested it might be hard water/mineral deposits. The rep recommended CLR (calcium, lime, rust remover), letting it sit for 15 minutes, then scrubbing with a nonscratch pad. I used a whole bottle, but it didn't help.

Does anyone know what this is? The toilet has CEFIONTECT, but to my knowledge, no abrasive has ever been used on it--and I'm not sure it would cause this problem even if it had been.

Thanks.

 

[Terry]

What year was this installed?

I sometimes use Dawn dish washing detergent and let that soak for a while.

 

[Sponsor]

 

[Reach4]

Does anyone know what this is?

It could be that you put a sulfuric acid drain cleaner into the toilet. I made that mistake once.

 

[trg12]

It was installed in 2016, and I've never used sulfuric acid or any other kind of drain cleaner in it. I have two of them, installed at the same time, and the second one, which is rarely used, doesn't have this problem. I could try Dawn dish soap, but do you have any idea what this might be that Dawn would clean it when CLR or just scrubbing with a toilet brush or nonscratch pad wouldn't? How much Dawn do you use?

 

[trg12]

Terry, how much Dawn do you use? Couple of squirts? Half a bottle? Whole bottle?

 

[Terry]

A couple of squirts, mix it up, let it set.

 

[trg12]

I tried it--it didn't do anything. Any other ideas? I can't understand what could be so tenacious that it could resist soap, scrubbing with the toilet brush, even CLR and bleach. And it seems to be getting larger.

 

[trg12]

No one has encountered this before? If it's on top of the CEFIONTECT, it should come off. If the CEFIONTECT has somehow been scraped off, then maybe the stain is in the porcelain, but it should still come off.

 

[HudsonDIY]

It sounds like a copper stain.
How it would have got there, well who knows?

https://www.plumbingsupply.com/getting-rid-of-blue-green-water-stains.html

 

[trg12]

Great article, thanks!

 

[Go with the flow Plumbing]

I would suggest getting a pumice stone. I have taken out some pretty deep scratches with pumice stone. You can get a porcelain touch up paint for Bathtubs at Lowe's.

 

[trg12]

Thanks, but this is a toilet, and it has a CEFIONTECT coating that abrasives will remove.

 

[Jadnashua]

Barkeepers friend is a REALLy fine abrasive that you might try. Since it's already stained, that probably wouldn't make it worse. But, first, you might try something like a Scrub Daddy pad or a Magic Eraser. Neither of those are hard enough to damage the glaze.

You might test the pH of your water.

 

[trg12]

Aaaaaaaand the answer is ... sodium bisulfate.

According to the article HudsonDIY linked to above, the blue/green staining is caused by acidic water pulling copper out of the pipes. It says, "When the copper-laden water is allowed to sit, it stains."

The article suggests using vinegar, which didn't work, or sodium bisulfate, which did. It's available as a pool chemical (e.g., pH Down or pH Minus).

This is the procedure I used:

Shut off the tank valve, flush, then pour in half a bucket of water, which further reduces the level in the bowl. Use an old turkey baster or wet-dry vac to suction out the remaining water. Pour a couple of tablespoons of the (granular) chemical over the stain and sprinkle a little water over it, just enough to moisten it so it can act on the stain. Leave it for 12 hours (it may not take this long; I didn't investigate shorter times). Rinse it down and repeat as necessary. No scrubbing required.

Thanks to all for your suggestions, especially HudsonDIY.