Chemical Disposal Advice - CalHypo

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
24,381
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I was clearing out some junk in the garage when I came across two very old (~4+ years old) cal-hypo bags. They are 16oz bags of what was 73% cal-hypo. In my pool, 32 oz of cal-hypo would add ~11ppm FC and ~7ppm CH but the water is already at 625ppm CH so I'm not keen on using any cal-hypo for chlorination.

The plastic bags containing the cal-hypo are still in good shape as far as i can tell (no tears or embrittlement of the plastic) but the outside product labelling is definitely faded with age and, possibly, chlorine vapors bleaching the dye on the labelling. My garage is not temperature controlled and can easily get up to 120F during the hot months. I can't leave my garage doors open during the day for air circulation because we'll get lizards and pack-rats galore.

So, I guess I'm left with two options - use the cal-hypo in the pool water or dispose of it somehow. Obviously I would not throw the stuff in the trash as that would be a fire hazard and illegal. Any thoughts on how to properly dispose of it? Or am I being silly and should just dilute it and add it to the pool through the skimmer?

Any advice would be most appreciated.
 
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Search your county website for household hazardous waste drop off location or pick up events.

Household Hazardous Waste (HHW) Program | Official website of the City of Tucson

ES Event Calendar | Official website of the City of Tucson Looks like they are open for collections 1 Saturday per month as well.

Yeah, I did look into that. Unfortunately they're not open again until Aug. 1st and we're likely going to be out of town those days. Also, being a Pima County resident (just outside the city limits), I'd have to pay the disposal fee ($10). That's not a big deal, but I'd like to dispose of it sooner rather than later...
 
Dilution won't help with adding it to the pool. If you dispose all of it there, you'll still get all the CH from it. You could put a little at a time to the sewer and it wouldn't hurt anything. You could use it to bleach out/sanitize toilets in the house and flush it. Assuming you don't have a septic system that would work, and not be harmful, or unethical.
 
Dilution won't help with adding it to the pool. If you dispose all of it there, you'll still get all the CH from it. You could put a little at a time to the sewer and it wouldn't hurt anything. You could use it to bleach out/sanitize toilets in the house and flush it. Assuming you don't have a septic system that would work, and not be harmful, or unethical.

Hey, now that's a great idea! Considering all the other junk we use to clean the toilets, cal-hypo power seems like a good idea. And we're on city sewer so no problems with a septic tank.


Cal-Hypo may have degraded some in the hot environment especially if any moisture got into the product. If it did, then it's the chlorine content that would have degraded to chloride and chlorate. The calcium would remain.

The package integrity seems good but it wouldn't surprise me at all if its degraded. It was, as best I can tell, from the previous homeowner as I have never purchased cal-hypo before.

I think I'll bring it into the house and transfer it to a secondary container for use as toilet cleaner.

Thank you all for the ideas.


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Sounds like a plan, but it makes me wonder, what is your makeup CH? It would be nice to find out some of the pool CH came from Cal Hypo. I'm sure you know, just wishful thinking on my part.

No worries. My tap water, last time I measured it is -

FC 1.5ppm
CC 0
pH 8.0-8.2
TA 120ppm
CH 280ppm*

* This is the minimal CH value as it varies a bit during the year and gets as high as 350ppm

When we moved in, the CYA was >180ppm and the pool was all cloudy. The CH was somewhere over 800ppm (I stopped at 800 to save reagent). I wasn't sure if it was a nascent algae bloom or calcium clouding but I just decided to not mess around with it. The previous owners were standard pool service users so I'm sure whoever was maintaining the pool was doing some kind of weekly trichlor/cal-hypo regimen (as I have buckets of pucks) which I totally don't get because the pool has a perfectly good SWCG??? (Still to this day can't figure out what they were doing)

I drained probably 75% of the water and splurged to have low TA/CH water trucked in. I could only get about 8,000 gallons by truck so the final top off was ~4000 gallon from the spigot (as best I could tell from timing how long the garden hose ran for).

I've been doing TFP now for years (and before home ownership as well on a small community pool in an HOA we rented in). So I was able to get the pool tooled up quickly which was a good thing because we moved to Tucson in July and my wife was 8-1/2 months pregnant at the time and in desperate need of the pool :)


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If it's still got some bleaching power to it, just use it in the laundry instead of liquid bleach.

Well, now I'm not sure I'll use it around the house as the stuff STINKS of chlorine. Every time I crack the lid to take a teaspoon out the stuff gives off the most noxious chlorine odor. I think that's pretty typical of high concentration cal-hypo as I suppose when you use it outside by the pool, the open air mitigates the odor. It's in a good, sealed container with a very tiny vent hole to avoid pressure build up, but cal-hypo smells terrible in my opinion and doesn't seem safe to keep indoors. I may just go the disposal route of dilution in a big basin of water, let it sit outside in the sun for a couple of days and then down the drain with it.

I've never bought the stuff before but now I'm pretty sure I never will.


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It doesn't smell different than household bleach you buy at the store. It can't because it's the same chemical. Bleach is bleach. It just smells strongly because it's about ten times as concentrated and is dry so dust can travel directly to your nose. Adding a tablespoon to the wash will be no different than a cup of household bleach. In fact, it may be a bit gentler on your clothes without the lye found in liquid bleach.
 
If it's higher concentration Cal-Hypo > 50% (say, 65% or especially 73%), just note that contact with organic materials can create a fire (see this link).

Wow. That's a horrible but very instructive story.

Enough said. It's going into a big basin of water and then disposal. No need to take risks with stuff like that.


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Oxidizers are always dangerous stuff. Once dissolved in water, your calhypo will just be liquid bleach with no more or less danger than any other bottle of bleach.

True, but most household oxidizers (peroxides, chlorine bleach, etc) are not concentrated enough to cause problems for the average household even in the case of accidental mixtures. I feel this discussion has convinced me that the downside risks to life, health or property outweigh any potential benefits for household use of the old cal-hypo powder....as well, I don't tolerate chlorine bleach in my laundry (mild itchy skin rash) and use only peroxide-based non-chlorine bleaches and OxiClean for the whites cycle ;)

However, as you indicated, perhaps my sensitivities to Clorox has always been from the excess lye and not the hypochlorite itself since swimming in my pool does not bother me one bit...THANKS!!
 
While Trichlor and other concentrated pool chemicals ain't no picnic, concentrated Cal-Hypo is worse by far with regard to self-sustaining fire. See the thread National Fire Protection Association (NFPA) Ratings that show that Cal-Hypo > 50% concentration and Dichlor anhydrous are both Class 3 oxidizers. This is one reason why what is normally sold is Dichlor dihydrate that is only a Class 1 oxidizer.
 
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