Calling All Chem Geeks (incl. THE Chem Geek) re: storing pool chems

Please read - I'm very anxious for any theories, or support of mine, re: leaching of muriatic acid causing thousands of dollars worth of damage in my crawl.

A year ago I had a new high efficiency heat pump installed. The inside unit is in the crawl under the house. In the first section of the crawl (where you can actually fully stand) is a cement patio, and this is where I have always stored my pool chems, including jugs of bleach, muriatic acid, and CYA. I live in Alabama and the garage and pool house just get so hot, the cool crawl seemed like the place to keep it.

Recently when we had a brief dip in temps I cycled on my heat for the first time since last Spring. Was I ever surprised when I saw everything in the house coated with tiny white flakes. A couple days later I put the AC on and the pungent smell of mold filled the air. I called my HVAC guy, David, and he began disassembling the inside unit in the crawl. The evaporator coil was filled with the stuff (in fact, ruined), likewise all the duct work including two new ducts I had done a year ago (I was going to replace 2 each year). The 30-year-old, fiberglass main trunk line was also full of it, and unfortunately, also black mold (presumably an unrelated and second problem). The *outside* of the main trunk was also full of the white flakes. David called it a strange oxidation of some type - he's never seen it before. He researched with friends in the business and no one has ever seen anything like it. It is his belief that all this "oxidation," the white flakes everywhere, started sometime in the last couple of months because he did the annual service and it wasn't there then.

David, meanwhile, has been working for several days replacing all the duct work, installing a new commercial-grade main trunk line that's even wrapped (they use these in hospitals), is going to install a relatively expensive UV light, is spraying even the new ductwork with a special germacide, and he also has had to install a new evaporator coil (he was able to return the old one under warranty).

I have to interject here--David is all about service, I mean you don't find guys like this much anymore. He's doing nearly $5,000 worth of work for $1500. I still can't wrap my head around this.

***This is what I really need ya'll to weigh in on:***

Last night he was showing me the new work in the crawl and he told me that he thinks there's a chemical contamination - he said he's constantly tasting something adverse, much like sucking on a penny. And then I tasted it, having licked my lips, and I was only in there for about 5 minutes. I lead him 6-7 feet away to the cement patio where the bucket of stabilizer and a jug of muriatic acid were. And it hit me. I said you know, there's something vaguely familiar about this taste I have, the penny-in-the-mouth taste, could it be that muriatic acid is leaching out of the jug, through the cap - that the cap is ill-fitting somehow (even though it was not mis-threaded, I checked)? The last time I used the acid was early August, at present the jug is about 9/10th's full. David said, of course acid is incredibly corrosive. In fact, there were even bits of the white stuff on some joists. Could this be the problem? I immediately removed it from the crawl.

Going forward, where to now store pool chems that should be in a cool place? Yes, I do have a quite large and nice pool house, and also a shed next to that, and they are in the lower yard so they would be a tad cooler than the garage, but still very, very hot.

I am so hoping that the problem is the muriatic acid because I want this never to happen again. Next time I would certainly not be so incredibly lucky to pay so little for all this abatement work. David's even going to replace the vapor barrier…

I've spent a couple of hours googling various strings of key words and eventually got hot onto a trail. I now believe that a $4 jug of muriatic acid has caused almost $5 grand of damage to the inside unit of my heat pump. Actually, that's not entirely fair. It could be a combination of a leaky old main trunk line and the acid vapors, since both moisture and acid highly contribution to zinc oxidation.

Galvanized metal has a nearly 100% zinc coating.

Zinc metal is very reactive with acids, esp. strong acides, such as hydrochloric (muriatic) acid.

Zinc [zinc oxide] is susceptible to WHTE RUST and often appears as WHITE POWDER or powdery white deposit.

White rust is simply the chemical compound, zinc hydroxide which forms when zinc is in contact with moisture or other chemical agents.

* * *

This really explains it all, from the white flakes on the galvanized main trunk line (white rust) to the white powdery deposits on some of the joists.

Since the ducts were so filled with black mold, it could be that the moisture--with or without vapors escaping from a muriatic acid jug--caused the chemical reaction. What's interesting is the tons of white powder *inside* the evaporator coil and in the old insulation that lined the main trunk line.

I just got off phone with HVAC guy and he is testing the system now. All the work is done, and tonight I will be breathing the highest quality indoor air I've probably ever breathed. I told him of my discoveries and he's right on board. At least we know what it is now, and the acid will never again be inside there. With him working just on labor and saving me thousands of dollars I'm also going to invest in a direct line dehumidifier this weekend.

Now, where to store the acid? Outdoors in the summer heat, behind the pool house or shed? Or contained in a plastic bin with a lid in the heat outdoors?

Elsie, always nice to see you here:)!

I know that any form of chlorine will off-gas and potentially rot any metal in the room. I had thought that the jugs of MA were OK, but apparently not... ?

I've always suggested chlorine gets stored outside in a plastic bin in the shade, I guess that's what needs be done with the MA as well. (DO NOT EVER!!!! STORE ACID AND CHLORINE IN THE SAME BIN!!!!!!!!!!!!!)

I'm as interested in this as you are and hope that the folks who really know will chime in.

Generally speaking, Muriatic Acid is worse than chlorinating liquid in terms of damage from gas leakage. Both bottles have caps that are intentionally designed to vent fumes when the pressure builds up. This is to prevent bursting of the bottle. A defective cap could leak continuously even with no pressure buildup.

Muriatic Acid stored in garages is known to rust bicycles and other metal nearby. If you go to a hardware store you will likely notice that metal shelves with MA have rust stains. So your theory is entirely plausible especially in an area with relatively poor ventilation (i.e. no wind regularly blowing through the area). The MA fumes are very destructive. I'm sorry this happened to you.

I store my MA in a pool box outside. There's nothing in the box I would be very sorry to lose and the box is open (with netting) on the bottom so gets some (but not much) ventilation. It's not ideal, but it works for me. I would not store MA in a pool shed since the heater and pump could get damaged. Even chlorinating liquid can be a little risky stored there, but is better than MA. If you have an open milk carton crate and some shady area of your property (say, behind the pool house, but not near any vent) then you can store MA and chlorine separately in such crates and the outdoor air circulation plus relative isolation should keep everything in good shape.

Richard

This one is an eye opener. Sorry about all the damage but your experience hopefully will cause others, including me, to take a better look at storing this stuff. I've had a full gallon and about 1/3 of another one in my basement/garage for probably 10 years now. Stored on a concrete floor, off in an area near metal shelving and near a copper pipe contraption laying on the bottom shelf just off the floor. Took a close look this morning. The end of the copper piping closest to the bottles has surface oxidation (copper oxide) but no signs of excessive rusting of the shelving or significant discoleration of the concrete under the bottles. I also looked at the bottle caps and there is NO pressure relief mechanism and these are the original bottles....old as I stated.
Elsie, the bottles you have are they the original containers and is there any ventilation at all in that crawl space? It puzzles me as to how things could happen so fast. Since you also had a mold situation that tells me maybe the humidity was real high which it easily could be in a crawl space. As I recall from chemistry too long ago, highly concentrated acid is called 'fuming' which simply means it reacts with the water in the air to cause a fog to form, thus the term fuming. Heavier than air the acid is now in solution and could collect on metal surfaces and rapidly oxidize that surface. You would need a major acid exposure though, like the caps weren't on or the bottles leaked. Crawl spaces usually are at a fairly constant temperature so the bottles wouldn't breathe that much. Not like they were sitting in the sun or in a hot container that cooled down at night. I guess the only consolation is you probably don't have any critters living in that area.
In any case, my stuff will be gone since I don't need it now. Yes, I'll dispose of it safely and responsibly.
Al

Thanks for the follow up :)

What about storing MA outside during freezing temps? (if I recall correctly, MA has a much lower freezing temp than water - but outside in Maine?) Also, do the MA gasses affect plastic (I assume not because the jugs are plastic, but it never hurts to ask and be sure ;) )

As shown in this post, the freezing point of full-strength Muriatic Acid (31.45% Hydrochloric Acid) is -46.8 Celsius which is -52.2ºF so much colder than even the coldest winters in Maine.

Half-strength Muriatic Acid that is, say, 15-16% Hydrochloric Acid is 15.5 grams of HCl in 100 grams of solution so 100-15.5 = 84.5 grams of water. (15.5 g HCl / 36.46 g/mole HCl) / ((100-15.5) grams water / 1000 grams/kilogram) = 5.03 m. So, 5.03 m * (-1.86C/m) * 2 = -18.7 Celsius which is -1.7ºF so barely below freezing.

So this means that storing full-strength Muriatic Acid outdoor should be fine, but storing half-strength outdoors could freeze.

Yet again, I find myself thanking you for your help!:)

If I can tap this resource 1 more time - Does potassium MPS (in 1 lb bags) outgas enough to damage the metals in the room it's stored in? I've got 17 bags and ~ nowhere to store them outside of the pump room (though, I do have a Styrofoam cooler I could put them in and leave outside).


You, and all the contributors here TRULY ROCK!!!!!!!!!!!


(Elsie, are you still with us here? I'm sorry to semi-hijack your thread:( )

Though I am not certain, I doubt very much that non-chlorine shock (MPS) has any significant volatility. It's not like Trichlor pucks/tabs that can offgas chlorine (which you can tell by the smell when you open up a large container of pucks). Also, the container for the non-chlorine shock shouldn't be vented so if well sealed it shouldn't be a problem.

But remember when it's below 0 F, the containers the MA is stored in get very, very brittle. Even hardened steel gets brittle and can shatter when it's that cold. I had a padlock on my gate I couldn't open when it was well below zero, and I whacked it with a pry bar and the hardened shank just snapped like an icicle! So imagine how fragile poly containers are!

I'm here, now anyways! I was on vacation Friday and I don't have a PC at home.

I have to say, it's really nice to be breathing such clean air, having an entirely new duct system. I was in the crawl Saturday vacuuming work debris from the vapor barrier, then decided to vacuum the whole thing even though I would have to "crawl" as the height gradually diminished. And I noticed something that could shed more light on this whole situation. The crawl takes water. I'd guess about 40% of the earth below the double vapor barrier is wet after a heavy rain we'd had recently (double because I laid a black one when I bought the place 8 years ago and when my HVAC guy put in new heat pump last year he laid a white, thicker mil over the black one). You can easily see it because you can see a shiny translucence of the black plastic when you put weight on the white plastic. I confirmed by pulling it up in a few places and then touching it.

So could it be that all this moisture is what caused the oxidation, and not the MA leaching from either a defective cap or some normal outgassing at all? But then you have to consider, if there's a double-layer of vapor barrier isn't it keeping the moisture from gravitating upwards/through the two layers of plastic? The black mold in the main trunk line could've been because it was old and leaky, and in Alabama we do have a lot of humidity along with the increased humidity from the damp earth below the vapor barriers, plus the pool is only 20 feet away which would serve to potentiate all this humidity assuming it can work its way into the crawl.

So I guess I will never know for sure what caused the incredible oxidation, or if it was a mixture of the two. Since I can't afford $5-10K to have a foundation specialist fix the problem, I'm going to install a dehumidifier in the crawl with a direct line (whose specs are for some 3600 sq. ft. when the crawl is about 1100 sq. ft.) and hope that this will keep everything good and well. It will run a lot, so I probably will have to replace it every couple of years.

Since the new trunk line is commercial grade and is a solid metal unlike the old one which was made of fiberglass which is a perfect environment for mold, and additionally is wrapped, and since all ducts are new and everything is sealed so well along with a UV light, I think I should be fine there--my HVAC guy said nothing will be able to grow in that environ. Upon inspection of the joists I see no rot whatsoever, and the walls are made of concrete block and there is no visible mold on them, so I'm hoping to not have any more nightmares in my lifetime. Statistically, at 55 that's not a crazy amount of time. But you can bet that I will go inspect the crawl on a monthly basis now that I am so aware of the potential for problems.

Even so, my MA and bleach will now be stored in open milk cartons *behind* the pool house, in the open air and in the shade, well away from the upper yard and pool.

Thanks everyone for weighing in!

My HVAC guy, David, just called to see how I'm liking the ultra-clean air inside my house and after I expressed my gratitude (again), I told him about the wetness underneath the vapor barriers, and he said that's *normal* - it's sweating/condensation and it can't hurt anything because it's under the plastic, i.e., that's what they're for (which I knew, but still didn't quite grasp apparently). So I am quite relieved. I'm going to get a dehumdifier anyway to protect what he just called an industrial-grade duct system. What an extraordinary service, and extraordinary man.

And you can bet I won't store any MA or bleach in my garage, either, where my car of course is along with my new toy, a Gary Fisher hybrid bike. :)

Elsie, glad you're breathing clean air!

Thanks for starting this so I remembered to ask my questions :cool:

I hope your pool and new duct work never cause you any problems, but if they do... you know where to find your answers :)

What's the best way to dispose of extra "old" muriatic acid? I have a partial bottle that I want to get rid of... have not used or needed it in years. I know I should not just pour it down a drain or onto the ground. Is there a safe way to neutralize it?

While I'm certainly noot an expert on hazardous chems, I think that filling a ~30 gallon garbage bin with water, adding the acid and then enough soda ash (pH up or Super Washing soda to neutralize it) would be sufficient to allow you to just dump the bin on the driveway or lawn. :)

1 gallon of full-strength Muriatic Acid (31.45% Hydrochloric Acid) is neutralized by 8.4 pounds of pH Up / Soda Ash / Arm & Hammer Super Washing Soda or by 16.6 pounds of 20 Mule Team Borax.

Excellent! Now I know what to do and how much neutralizer to use.

It will actually take less than the amounts I indicated, especially for the soda ash, because it will result in carbon dioxide outgassing that will also raise the pH. Figure about 4-1/2 pounds instead of the 8.4 pounds (per gallon of acid). You should mix the soda ash in a bucket of water and then slowly add the acid to it. Wear goggles as there will be bubbling of carbon dioxide when you add the acid and you don't want anything splashing into your eyes.

Be careful not to breathe the fumes from the muriatic, as well as any that may be created while doing the mixing. MA fumes are truly AWFUL.