Bartier Disinfection Index

[waterbear]

I see you said that in your earlier post. Sorry I missed that the first time. If we try to use monochloramines for killing algae, then that will be a tricky combination of adding chlorine and ammonia. If CYA is present, then after the algae is killed, it will be virtually impossible to shock to breakpoint to get rid of the monochloramine, though it's possible a non-chlorine shock could do the trick.

Thanks for your comments. They are helpful.

Richard

Actually, the use of monochloramines for killing algae is not a new practice. Many 'old time' pool guys would add per 20000 gal water 1 gal anhydrous ammonia and 8 gallons of 12..5% hypochloruous acid (50 ppm) to form monochloramines in the water. Filtration is shut off for 24 hours and then an additional 8 gallons of chlorine is added and filtration turned on to destroy the chloramines. This is similar to the use of 'chlorine enhancers' that are based on inorganic ammonia compounds and are used to kill algae. They do create a huge chlorine demand in their aftermath. Perhaps PoolDoc (Ben) would have some more insight into this older practice.

Also, my understanding of MPS is that it will not break down chloramines....this info comes right off the DuPont Oxone website. They work by having a residual in the water to oxidize organics before choramines can form. This is a quote
" Does Oxone® reduce chloramines?
Products containing Oxone® prevent chloramines from forming by oxidizing contaminants. Regular oxidizing with Oxone® keeps contaminant levels to a minimum, so the water remains clear and sparkling, allowing you to enjoy longer periods of uninterrupted swim time. And because Oxone® is chlorine-free, you don't have to worry about high chlorine levels; chloramines; unpleasant odors; or burning, irritated eyes."
Here is the link
http://www.dupont.com/oxone/faq.html#a4

I can understand the benifits of MPS with an indoor pool but the caveat seems to be that a residual of MPS is required in the water at all times for them to be effective in the prevention of the formation of chloramines. I see no real advantage to their use in outdoor pools.

The only other non chlorine shock I am aware of is sodium percarbonate, which from my understanding, is no longer being used because of the effects it had on ORP controllers. It is still employed in limited use with conversion of biguinide to chlorine but I doubt it is really any better than chlorine for that purpose.