Shelf Life of test kit reagents

Hello,

I have read the chart about the shelf life of the reagents. It's very helpful, but I still want to run this by you all.

My kit (PS233) is just turning 5 years old. I have never replaced anything in it, and there's still lots left of some of them. I keep them capped, in a stable environment. They have never been subjected to prolonged heat or cold or moisture. Looks like from the chart, everything should be replaced except for a few things that remain good for "years".

Do you all replace them that frequently? Just curious. Since mine is 5 years old, guess I should just bite the bullet. I went to the Taylor website, and all I can say is it might be worth paying postage directly from them. My local pool store carries them, but their pricing is about 2 or 3 times higher.

Thanks for any input, as always.

Sandy

I find I just keep my refills in a dark cabinet that doesn't get hot and they seem to be fine. That's probably a mistake, but...it works for me.

I keep my bulk refills in the fridge and only open them to refill the little bottles. Most chemicals when refrigerated and kept dark and away from oxygen will last a long time.
Al

The FAS titrant is probably the most unstable and should probably be replaced yearly. If it has turned pink it is decidedly bad!
The DPD powder will work even if it is black but if it clumps I would replace it.
I have seen pH reagent (Phenol Red) go bad after a few years. (easy to check if you have the acid and base demand reagents. If they don't cause the color to change the reagent is bad).
If they are kept tightly capped and have not been exposed to temperature extremes the calcium hardness and TA reagents should be fine. I don't really know the shelf life of the CYA reagent but I have gotten exactly the same results from 5 year old reagent and brand new.

Hope this is helpful.

Well, I DO have a definite rule for when to replace the FAS-DPD powder:

If I open the container and what's inside is moving of it's own accord I:
1) Replace the cap, closing it
2) Get rid of it.:eek:

Not specific to PS23x, which is obviously named for a brand of deodorant-antiperspirant... or a public school in Brooklyn. :D

I store all reagents in an unconditioned space (a closet) -- but not in the garage or an out building, in order to protect them from heat/cold. My understanding is that acids (sulphuric and the like) will hold up for years and years. That’s forever in my book. FAS-DPD components (like the R-0871 titrant that comes in a suspiciously darkened container), however, are pretty vulnerable.

Someone on this board buys a quarter pound (or maybe a full pound?) of DPD R-0870 powder, wraps it in plastic and stores it in her refrigerator. (It just sits back there next to auntie's Prune Salsa, a gelatinous cube of preserved fruit, circa 1965.) I think I'm going to start purchasing DPD powder this way—just as soon as I use up all the pesky 10 mL vials I have scattered about the house.

And more calcium indicator. You can never have enough calcium indicator. I have the quart size. That's good, but I’m going for the gallon next time. It will really impress my neighbors, who have to live with puny 3 /4 oz titrators.

I'm another one who is still using stuff from years ago and it seems fine. I actually use my OTO kit for a lot of my day-to-day testing so some of mine last a long time before I need to replenish. Uncle Al keeps me supplied with cya reagent, etc. when I do need refills since he buys things in bulk. He doesn't have a bunch of boys who eat non-stop at his house like I do. No room in my frig for pool testing chemicals!

Quote:

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Originally Posted by polyvue

Someone on this board buys a quarter pound (or maybe a full pound?) of DPD R-0870 powder, wraps it in plastic and stores it in her refrigerator.

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I vacuum seal mine with my FoodSaver! Air (oxygen) and moisture are the enemies of this reagent.
I just opened up a new one (I put it in smaller containers before I seal it) from three years ago and it's perfect! I don't keep it in the fridge but is does stay in the cabinet under the sink in the guest bathroom (which is close and convenient to the pool so it's my testing station.)

When you're ready to get new stuff, by all means buy direct from the manufacturer. i've found that to be considerably less expensive. i was able to buy much larger amounts for the same or less than the tiny bottles that come in the pool stores.