Is Oxy deposit due to hard water?

[jmc]

I mostly use wiz-oxy to clean kit and sometimes I leave it in FVs etc for a soak until I have time to finish off cleaning it.

I wondered if others have the same problem I get.

If I leave it to soak I often get a powdered / crystal deposit form.
I make sure the oxy is dissolved fully before I use it but the deposit seems to appear after a few hours

I thought it might be the additives coming out of the oxy but I'm wondering now if its down to my hard water (> 300ppm equivalent CaCO3.)

My thoughts are that Sodium Percarbonate (active ingredient in Wiz-Oxy) turns to Sodium Carbonate (after O2 produced) and this reacts with Ca++ ions in hard water to form CaCO3 (chalk) ?
Sodium Carbonate is used as a water softener to do just this.

It would be useful to see if others get the same problem, and if they did whether they also had hard water.

I may also try an experiment with wiz-oxy dissolved in bottled water with Low Calcium to see if that changes anything.

[Andy]

I get the same if I leave it soaking for hours so now don't leave it working for anywhere near that time.

I'm also in a hard water area.

[boingy]

Yep, I've had the same.
I'm no chemist so I don't know if it is to do with the water hardness but I now limit Oxy to 20 minutes or thereabouts.

[jmc]

Thanks for the replies.
Cheers John

[asd]

Hi,

Same prob, but I solve it by pouring in some vinegar, which dissolves it.

[Blackaddler]

There's a fair amount [probably >30%] of sodium carbonate [soda] in oxi. It has that soapy feel.

I've had the same deposits with soda in hard water, so this may be the culprit.

I've recently been using some Vanish Oxy-Plus, which has some water softening agent added, and it doesn't seem to leave deposits quite so much.

[jmc]

Thanks for replies.

I've done some more reading up on this and thanks to other members feedback it definitely looks like it is calcium carbonate being deposited due to my hard water.

Most useful link supplied by barneey
http://www.bertusbrewery.com/2012/11/su ... clean.html

PBW is awesome. Unfortunately, it's also expensive. Many homebrewers (myself included) turn to Oxiclean as a suitable alternative. It's main ingredients are pretty similar to PBW -- sodium carbonate (washing soda), and sodium percarbonate (the oxidizing agent). The problem is: Oxiclean simply doesn't work as well as PBW. It doesn't remove caked on crap as well as PBW does, it doesn't rinse away as easily, and if you have hard water, it can leave hard water scale on your equipment.

The article discussing adding a chelating agent like sodium metasilicate (as used in PBW) to stop the hard water scale deposit forming.

I believe kev888 uses a 2:1 mix of sodium percarbonate and sodium metasilicate with some calgon to further reduce scale deposition.

[Mr. Dripping]

I've had exactly the same thing when I left a corny keg soaking overnight in the stuff.
I tried all sorts to remove it and I ended up having to do another soak with water dosed with a heavy dollop of phosphoric acid to get it to come off. Never again

[imark]

Suspected this myself for a while now. Thanks for confirming.

[Nofolkandchance]

I buy the 25kg sacks of this and it's awesome. http://mistralni.co.uk/products/sodium- ... ultra-pure

Leaves all equipment sparkling and no residue/deposit

[Nofolkandchance]

Forgot to mention I'm told it's one and the same as the wilko bru cleaner steriliser