Cleaning Toilets

[goeasy123]

Is there a chemist out there that understands chelators?

Is there a chelator for calcium that would work to remove the deposites in marine toilets, but not act on the metal or plastic parts?

Here's a good description of how a chelator works, but this one is for ferrous oxide (rust)...

https://www.youtube.com/watch?v=mwxwABnAsRU

[wsmurdoch]

I use citric acid, a coffee measure cup every two days or so flushed down the head. It is a powder solid. It is odor free. It not only decomposes carbonate salts, but also as a chelating agent, it also increases the water solubility of calcium and magnesium salts. While a weak acid, it is trivalent with three acid groups per molecule making a nice buffered acid solution between pH 2 and maybe 8. It's available on Amazon and easily stored in used PET peanut butter or mayonnaise jars.

As an acid it will convert the insoluble calcium carbonate to the soluble calcium citrate and carbon dioxide. You will see the bubbles. As a chelation agent it will increase the solubility of calcium attacking both struvite (calcium ammonium phosphate and/or magnesium ammonium phosphate) and calcium urate.

Citric acid is relatively cheap and not too hazardous. Think lemon juice. Check Amazon.

[goeasy123]

Originally Posted by wsmurdoch

I use citric acid, a coffee measure cup every two days or so flushed down the head. It is a powder solid. It is odor free. It not only decomposes carbonate salts, but also as a chelating agent, it also increases the water solubility of calcium and magnesium salts. While a weak acid, it is trivalent with three acid groups per molecule making a nice buffered acid solution between pH 2 and maybe 8. It's available on Amazon and easily stored in used PET peanut butter or mayonnaise jars.

As an acid it will convert the insoluble calcium carbonate to the soluble calcium citrate and carbon dioxide. You will see the bubbles. As a chelation agent it will increase the solubility of calcium attacking both struvite (calcium ammonium phosphate and/or magnesium ammonium phosphate) and calcium urate.

Citric acid is relatively cheap and not too hazardous. Think lemon juice. Check Amazon.

Thanks. And I'm guessing it's safe with stainless steel and bronze. Although it might take the surface Fe out of the SS?

I have a SS pipe from the black water tank to the bronze hull fitting. It has two ball valves in it. I'm paranoid about damaging any part of that string as it's a major (cutting out structural components) job to replace it. Hence the concern about long term effects of using any chemical.

[wsmurdoch]

I guess I have 4 liters of water in a flush and 30 g of citric acid in a coffee scoop. 30/4000=0.0075 so 3/4 of 1%. Then rinsed later with the next flush. I'm not too worried. I have thought about dissolving the citric acid in water, putting it in a squeeze bottle and addind a bit at each toilet use, but I have never gotten around to trying it although it seems like a good idea to me.

I also add two coffee scoops of sodium nitrate when I add the citric acid to give the bacteria in the holding tank an oxygen source and stop them from making H2S. Others are (were) using sodium perborate (with suspected health problems) or sodium percarbonate as the oxygen source.

[peghall]

Distlled white vinegar is inexpensive and available from most grocery stores. One or two cupfuls (no more) flushed all the way through the system weekly will prevent mineral buildup in the bowl and plumbing. Distilled white vinegar will also remove buildup, but it's so labor intensive (people who claim it won't work haven't learned that the vinegar has to be replaced about hourly to work) that muriatic acid --available from most hardware stores--is a better choice to remove a serious buildup.

Like most things, prevention is cheaper and easier than cure.



--Peggie

[peghall]

I REALLY hate to break it to you, but urine is so corrosive it'll turn any metal--even 316 SS--holding tank into a colander in 5-10 years. If it can eat through SS tank walls, it has to be eating through that SS pipe if sewage is sitting in it.



You can slow the damage down if you can thoroughly rinse that pipe out after every use--which would require also rinsing out the tank--to flush plenty of clean fresh water through it and also put a shutoff valve on it to keep tank contents out of it except during use. I'm aware that what I'm recommending here would be a major PITA, but not as much of one as having that pipe spring a leak--which it WILL do anyway...and without knowing how long that pipe has been in the system and whether sewage sits in it all the time, I have no idea how soon it may happen.



--Peggie