# Muriatic Acid in holding tank



## svzephyr44 (Jun 26, 2000)

My guess is that my holding tanks and lines are full of crud. Can I put a muriatic acid solution (4:1) in them? They are standard black plastic (I presume some form of plastic) tanks.


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## Multihullgirl (Dec 2, 2010)

Here's what Peggie Hall, the "Headmistress," has to say about that:

https://groups.google.com/forum/#!topic/rec.boats.cruising/lmvR9v517-o


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## RichH (Jul 10, 2000)

Id suggest the usage of an inhibited Hydrochloric (muriatic) acid used in commercial boiler descaling compounds. Muriatic (HCl) is compatible with epoxies, and chemically should be OK with polyester based FRG.
I do this treatment periodically to help dissolve sludge (accumulated carbonates - solids that form due the mixing of sea water and uric acid). 
Product, same as used for descaling a marine engine: RYDLYME Marine: The Ultimate Biodegradable Marine Descaler! | RydLyme Marine


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## MarkofSeaLife (Nov 7, 2010)

svzephyr44 said:


> My guess is that my holding tanks and lines are full of crud. Can I put a muriatic acid solution (4:1) in them? They are standard black plastic (I presume some form of plastic) tanks.


Muriatic acid comes in plastic bottles, undiluted.

So why wouldnt you be able to put it undiluted, except for resident crap, into plastic hoses and into a plastic tank?

Go for a sail with empty tanks and chuck a gallon in and slosh it around on each tack for a few minutes, say half an hour and then flush with lots of salt water.

Pump out at sea well offshore or at your favourite station.


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## svzephyr44 (Jun 26, 2000)

Thanks all. Think I will try the vinegar route first - have used it before but not let it stand for 24 hours. If that does not solve the problem then go to a dilute muriatic acid next if necessary.


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## SVAuspicious (Oct 31, 2006)

MarkofSeaLife said:


> Muriatic acid comes in plastic bottles, undiluted.


"Muriatic" is another name for hydrochloric acid. What you buy on the shelf in a hardware store for pool cleaning, drain cleaning, and masonry cleaning that is labeled Muriatic Acid is diluted already, generally 30 - 35%.

Very important, to quote my Jr. High School science teacher Dr. Hunsucker and paraphrase Peggie Hall: "Do as you oughta, add acid to watta." Adding the two in the other order will result in spattering and risk of burns. Eye protection is advisable.


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## capta (Jun 27, 2011)

If you are going to use Muriatic Acid in any system, you have to be absolutely certain that there is no metal, ANYWHERE in that system the acid could reach. A valve, hose fitting, even a valve stem of metal and you could be opening yourself up to complications down the road. How are you going to get this out of a tank? Is your deck fitting for pump out metal? What about the shaft on your overboard macerator pump?
I suggest extreme caution with this acid.


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## Samuelmonosov (Mar 7, 2014)

The problem is where the acid is released. Check with the harbor master about pumping it out of the bilge, and with the coast guard re overboard dump. Another concern may be eating through the gaskets in your waste system. There are several natural septic system cleaners which use natural enzymes to break down the crud. You can get them cheap at Home Depot. 


Sent from my iPad using Tapatalk


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## Minnewaska (Feb 21, 2010)

If your hoses are scaled already, I find it a bit hard to believe that some acid that washes past them will do much good, particularly vinegar. Maybe its a better prophylactic. Maybe it would loosen sludge in the tank, not sure. Further, if you dislodge large chunks of scale, they are very likely going to jam up in the smallest place. Murphy's Law says that will be in the less accessible location for you to get to, when you have to disassemble the system to unclog it.


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## MarkofSeaLife (Nov 7, 2010)

Minnewaska said:


> If your hoses are scaled already, I find it a bit hard to believe that some acid that washes past them will do much good, particularly vinegar.


I cant see vinegar doing any good at all. It wont even wilt a lettuce leaf in a salad.

Just stinks the boat out for a few days.


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## Brewgyver (Dec 31, 2011)

Samuelmonosov said:


> (snippage)There are several natural septic system cleaners which use natural enzymes to break down the crud. You can get them cheap at Home Depot.


While the enzymatic products may help with sludge, they will do nothing for the crystallized uratic salt buildup. The problem is well known in the plumbing industry, especially in commercial buildings, and has been around forever, but exasperated by the introduction of ultra-low water consumption fixtures, not to mention water-free urianls. Naturally, the chemical industry started marketing Uratic Salt Removers at least 25 years ago. All of the products marketed for this problem STILL use HCl as the active ingredient.


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## benesailor (Dec 27, 2012)

> While the enzymatic products may help with sludge, they will do nothing for the crystallized uratic salt buildup. The problem is well known in the plumbing industry, especially in commercial buildings, and has been around forever, but exasperated by the introduction of ultra-low water consumption fixtures, not to mention water-free urianls. Naturally, the chemical industry started marketing Uratic Salt Removers at least 25 years ago. All of the products marketed for this problem STILL use HCl as the active ingredient.


BINGO ! Thank you

Those of us with hard water and septic systems deal with these issues all the time. Enzyme's don't do squat. I pour acid down my drains to "clean out" the pipes about twice a year. You learn after you replace ALL your plumbing.


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## newhaul (Feb 19, 2010)

Back in the old days when I ran sewage systems for the US navy we used citric acid to remove the scale in the urinal piping on the ships worked good and is and was non caustic to rubber and the various metals in the system also it is not harmful to people or the environment heck you could eat it if you really want to but I would not recommend that.


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## Don L (Aug 8, 2008)

I personally don't feel vinegar does anything unless you started using when the system was new and you used it very regularly. It is just too weak.

An acid is an acid, but I feel it is better to use ones more designed just for home scale removal use like CLR

Using acid is just for the hoses etc. it isn't going to clean the holding tank. The amount you would have to add to maintain a pH lower enough to remove scale in a holding tank that has sludge in it would be a lot.


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## pdqaltair (Nov 14, 2008)

I've done a fair amount of testing of de-scaling chemicals, both for industrial and sailing head applications, and the most widely available chemical that I liked was CLR.

Hydrochloric acid. Effective. Murder on most metals, and not good for stainless. Requires care, Will destroy nitrile (cracks) and nylon (melts--not just ropes but fittings too). I wouldn't use it unless I was 100% certain there were no nitrile or nitrile parts in the system... and both are common in certain brands.

Lime-a-way. Sulfamic acid. Bad on nitrile (heads other than Jabsco, hoses) and acetal (strainers).

CLR. Lactic acid. Probably the best chemical compatibility and pretty aggressive as well. There is risk to Hytrel and ABS, but I've not seen those in heads.

Vinegar. Weak acetic acid. From what I've seen, this is mostly in your head. Certainly it won't attack established layers. Probably works for folks that flush enough water and use it very regularly... and even then CLR would be more effective and economical, if the does were equivalent. But folks do like their home remedies. They'd be better off using the vinegar and veggy oil on salads.

---

Always a compromise.


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## dorymate1 (Dec 6, 2011)

We use a product from tract ecological called Sew Clean check it out Welcome to Trac-Online


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