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

[chem geek]

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

[Poconos]

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

[waste]

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 )

[chem geek]

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.

[waste]

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 )

[chem geek]

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.

[CarlD]

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!