Sodium Dichloroisocyanurate as Drinking Water Treatment?

[nigelmercier]

Further to this thread ...

When did you last disinfect your shower head?

The thread linked above diverged into disinfection of water tanks, which was also useful. I had previously used Milton tablets for this, but I may have found a cheaper and more powerful alternative. I have bought some "mini" stabilised chlorine tablets meant for spa pools (link). They are about the diameter of a pound coin, and twice the thickness, so will easily drop into the water tanks.

The tablets are Sodium Dichloroisocyanurate Dihydrate, rather than Sodium Hypochlorite. Obviously the cyanide (CN) aspect is a bit of a concern, but the Wikipedia article says "... As a disinfectant, it is used to sterilize drinking water, swimming pools, tableware and air, fight against infectious diseases as routine disinfection...".

The dosing instructions say one tablet will raise the free chlorine level by 1ppm (1mg/l) in 1000l of water. For my 240 and 350 litre tanks this is ideal for an initial shock, but too strong for continuous use where 0.5ppm is more appropriate. More information at WHO Food Additives. I generally drink bottled water (as it is cold), but use tap water for coffee. I think I may have to use the bottled water for all consumption if I adopt this regime.

Any thoughts, especially from chemists named Vic?

 

[Malish]

I use these, cheap as chips, never had an issue:

http://www.ebay.co.uk/itm/10-Tablet...825597?hash=item3d201dbfbd:g:EpIAAOxyrrpTjGqE

 

[captainboo]

I use these:

http://www.cleantabs.co.uk/mega-tabs.php

which also contain Dichloroisocyanurate as the disinfecting agent so yours are probably similar but depends on the concentration in your tablets.

 

[nigelmercier]

I use these, cheap as chips, never had an issue...

Interesting, thank you.

Dosage: one 167mg tablet (also Sodium Dichloroisocyanurate) per 20-25 litres, cost 10p.
My tablets are 3.2g (20x 167mg) so should be OK for 400 litres, cost 5p.

I use these which also contain Dichloroisocyanurate ...

MSDS for Clean Tabs products here. Troclosene Sodium is indeed Sodium Dichloroisocyanurate

 

[VicS]

Further to this thread ...


The thread linked above diverged into disinfection of water tanks, which was also useful. I had previously used Milton tablets for this, but I may have found a cheaper and more powerful alternative. I have bought some "mini" stabilised chlorine tablets meant for spa pools (link). They are about the diameter of a pound coin, and twice the thickness, so will easily drop into the water tanks.

The tablets are Sodium Dichloroisocyanurate Dihydrate, rather than Sodium Hypochlorite. Obviously the cyanide (CN) aspect is a bit of a concern, but the Wikipedia article says "... As a disinfectant, it is used to sterilize drinking water, swimming pools, tableware and air, fight against infectious diseases as routine disinfection...".

The dosing instructions say one tablet will raise the free chlorine level by 1ppm (1mg/l) in 1000l of water. For my 240 and 350 litre tanks this is ideal for an initial shock, but too strong for continuous use where 0.5ppm is more appropriate. More information at WHO Food Additives. I generally drink bottled water (as it is cold), but use tap water for coffee. I think I may have to use the bottled water for all consumption if I adopt this regime.

Any thoughts, especially from chemists named Vic?

No problems. It's a substituted cyanurate, not a cyanide

Widely used as a convenient and stable source of chlorine for water sterilisation, tank cleaning etc

Use at the dose rates recommended.

Main hazard seems to be release of chlorine gas on contact with acid ... but that applies to hypochlorites too.

 

[nigelmercier]

Excellent, thanks Vic.

 

[ip485]

Interesting.

I have tried these before and while they may well have done the job, the water still had a smell to it after being left a week. With pretty large tanks the cost is also a factor, as I tend to fill the full 300 gallons and then run it down until nearly empty.

Following on from the last thread I have just tried Elsil (one bottle treats 300 gallons at around £9 a bottle) and so far the results have been remarkably better and it appears a great deal more effective - well at least in preventing any smell from the water at all. At the moment the water was treated two weeks ago, so will see in another couple of weeks.

 

[EdWingfield]

Describe the smell, the taste. Swill it around the mouth and spit it out.

 

[VicS]

Interesting.

I have tried these before and while they may well have done the job, the water still had a smell to it after being left a week. With pretty large tanks the cost is also a factor, as I tend to fill the full 300 gallons and then run it down until nearly empty.

Following on from the last thread I have just tried Elsil (one bottle treats 300 gallons at around £9 a bottle) and so far the results have been remarkably better and it appears a great deal more effective - well at least in preventing any smell from the water at all. At the moment the water was treated two weeks ago, so will see in another couple of weeks.

Because NaDCC is, like hypochlorite, just a source of chlorine there is a similar potential for a lingering chlorine taste if one is a little heavy handed with it.

I use Milton for a small tank and have learned that it is easy to overdose and have unpleasant tasting tea as a result! I now measure the volume of Milton I use carefully.

Elsil is I believe hydrogen peroxide based. Obviously there is no potential for any taste changes or residual smell but I have always understood it to be a less effective sterilising agent than chlorine although presumably enhanced by combination with traces of silver.

 

[Spirit of Glenans]

You can also find discussions on these products on the home brew forums.

 

[ip485]

Yes I gather from the previous thread that the key is the combination with Silver and I agree it didnt give the water any taste or smell what so ever. In fact the water seemed really fresh without any of that slightly stale aspect to it even before it turns a little smelly when you first run the tap or shower. Early days but might have finally cracked it. If it does I will use the Elsil in preference, or a similiar peroxide silve combination.

 

[thinwater]

I did a bunch of testing for a series of articles in Practical Sailor.

http://www.practical-sailor.com/issues/37_55/features/Keeping-Water-Clean-and-Fresh_11745-1.html

The bottom line is that:
1. Puriclean was top choice, because...
2. The residual is MUCH more stable then bleach or peroxide alternatives. This means the tank stays fresh when the boat is unused for weeks or months--often the resisdual is enough to protect the next fill-up, if the tank was say, 30% full--and...
3. It tends to be more effective because of the increased residence time, and ...
3. It is far less corrosive to aluminum than bleach.

The tabs are also very convinient.

It is still easily removed by a carbon block filter. Carbon removes any oxidant by allowing itself to be oxidized.

 

[ip485]

I dont see how you add Puriclean easily to tanks - it suggests some type of sachet that is left to soak?

 

[EdWingfield]

It might help the discussion if you all stopped obsessing about chemistry, and started thinking about micro-biology?

 

[Yngmar]

I use these, cheap as chips, never had an issue:

http://www.ebay.co.uk/itm/10-Tablet...825597?hash=item3d201dbfbd:g:EpIAAOxyrrpTjGqE

+1

Been using the same, although I bought mine for a lot less than that here ;-)

No problems, no funny taste when dosed right (I did overdose once and had funky tea - lesson learnt). I drink from the tank boiled and cold after initial flushing with lots of bleach.

 

[Gwylan]

Further to this thread ...


The thread linked above diverged into disinfection of water tanks, which was also useful. I had previously used Milton tablets for this, but I may have found a cheaper and more powerful alternative. I have bought some "mini" stabilised chlorine tablets meant for spa pools (link). They are about the diameter of a pound coin, and twice the thickness, so will easily drop into the water tanks.

The tablets are Sodium Dichloroisocyanurate Dihydrate, rather than Sodium Hypochlorite. Obviously the cyanide (CN) aspect is a bit of a concern, but the Wikipedia article says "... As a disinfectant, it is used to sterilize drinking water, swimming pools, tableware and air, fight against infectious diseases as routine disinfection...".

The dosing instructions say one tablet will raise the free chlorine level by 1ppm (1mg/l) in 1000l of water. For my 240 and 350 litre tanks this is ideal for an initial shock, but too strong for continuous use where 0.5ppm is more appropriate. More information at WHO Food Additives. I generally drink bottled water (as it is cold), but use tap water for coffee. I think I may have to use the bottled water for all consumption if I adopt this regime.

Any thoughts, especially from chemists named Vic?

We have had Aquaclean for several years and found it fine. Since the major ingredient is Sodium Dichloroisocyanurate, we will be looking for that.
The big tablets that do 200 litres at a time and that's good.

But we do have an inline filter, that must have made a difference.

 

[macd]

It might help the discussion if you all stopped obsessing about chemistry, and started thinking about micro-biology?

OK, I've thought about micro-biology.
Will my tank be cleaner now?

 

[VicS]

It might help the discussion if you all stopped obsessing about chemistry, and started thinking about micro-biology?

please explain the microbiology involved

 

[Daydream believer]

It might help the discussion if you all stopped obsessing about chemistry, and started thinking about micro-biology?

What-- As in brewing beer??
yes !! if that is what you mean then a much better idea

 

[EdWingfield]

Now you've thought about micro-biology Mac, you might conclude that the only way of knowing if your disinfection, or routine dosing is successful, is to get a lab analysis?

I have done that. I know that my method of disinfection and dosing produced a satisfactory result.

For anyone who is interested, at winter lay-up my tanks are close to empty. I add heavy disinfectant plus a few litres of water. In spring I empty the tanks and refill with the correct dosing according to the manufacturer's instruction. I continue this throughout the season.

Much less likely to be a problem for yotties are non-microbials eg. hydrocarbons, Fe or phenols. A simple test for you to carry out is to get a clean glass. fill it with tank water, hold up to daylight. Q? is it crystal clear? Are there gubbins in suspension? Can you detect an aroma? Give it the taste test with a clean palette.

Be guided by your common-sense.