Water Changes

[HenryC]

All the tests I have done was right after dispensing the water. I have never been concerned about whether chlorine would dissipate after 24 hours or not since I refill my pond directly from the tap (no pretreatment chamber). I'm sure that here in FL, if you fill a container with chlorinated water and leave it in the FL sun that the chlorine will dissipate, just not sure how long it would take.

[Roddy Conrad]

Sunlight will not noticeably destroy the chlorine in makeup water to a pond. If that were the case, how could millions of us so successfully maintain our swimming pool water with chlorine?

[Rod L.]

Interesting points, but let me add another. I have a pool in South Georgia, but it might as well be Florida and here some observations that might like to comment on in regards to chlorine and it's stability.

1. With a stabalizer and proper PH, my pond chlorine level stays in great shape with very little chlorine addition over a weeks time.

2. Without the stabalizer and proper PH, the chlorine will dissapate in a day sometimes, depending on the amount of direct sunlight coming in (talking about a cloudy/rainy day vs no clouds or rain). My pool is in direct sunlight all day with absoulutely no cover of any sort.

3. No. 2 holds true whether I am using liquid chlorine or chlorine sticks, which have a certain amount of stabilizer added to them as part of the stick).

Based on these observations, I would have to conclude that there is more to this equation than just sunlight.

Rod L.

[Roddy Conrad]

Rod Lawton is correct in that if the pH is allowed to go to acid values, meaning below 7, the chlorine is much less stable in the swimming pool, disappearing in a single day. That is why the swimming pool stores sell you either soda ash (sodium carbonate) or baking soda (sodium bicarbonate) to keep the swimming pool pH in the range where the chlorine level will be stable. I maintain my swimming pool alkalinity the same way I maintain my pond alkalinity, by routine addition of 12 pound bags of baking soda from Sam's Discount store.

That means a water gardener with a dirty pond and no practically alkalinity won't burn their fish with a water change without dechlorinator. That also means that a conscientious koi keeper, who maintains the pH in the 7.5 to 9 range, and is fanatic about a clean pond with no plants is guaranteed to kill his/her fish with significant water changes without dechlorinator.

[MikeM]

Roddy: The chlorine discussion has been very interesting. There are other additives to drinking water in different areas for minimizing corrosion, etc. Observations on them?

[Roddy Conrad]

The standards for drinking water and the allowed additives covers a very long list, some of which are of no concern for ponders. I will discuss the ones of real concern, so you may know what to expect when you open the tap of your public drinking water.

The specific source I used for the numbers below is found on line at the following web site, where each of many water additives can be clicked up for review:

http://www.nap.edu/openbook/0309033381/html/1-1.htm

Chlorine can be added to 30 ppm, or calcium hypochlorite up to 20 ppm, while meeting standards for chlorine content. Ammonia can be added to 5 ppm to convert chlorine to chloramine, and ammonium sulfate can be added up to 25 ppm (which would provide ~6 ppm ammonia content). If you get these maximum levels in your actual water while using standard dechlorinator practices, you may get into trouble with the fish!

Potassium permanganate can (and is) used in drinking water up to 10 ppm levels to make the drinking water safe to drink. In fact, some ponders do report their tap water occasionally being pink with active potassium permanganate when the water company is using it for maintenance activities in treatment plants. This is of no concern for human consumption, in fact it will cure some human medical ailments at that dose in drinking water, and one pond supply store owner in San Jose, California reported her entire Vietnamese village was saved from extinction from a stomach bacterial infection by everyone in the village drinking a dilute PP solution. However, if you tap water is pink during a water exchange, use enough dechlor or hydrogen peroxide to get rid of the pink color (unless you want to use tap water as a low level PP treatment!).

Calcium bentonite is added to drinking water up to 15 PPM to aid human health, my wife and I drink a slurry of calcium bentonite daily to improve our health and chances to live to a ripe old age (we are now 62 years young).

A variety of phosphate compounds can and are added to drinking water to reduce pipe corrosion and to kill mussels in the water system. My tap water runs a level of measurable phosphates in the 5 to 30 PPM range all year long, for example. This helps green water algae grow like crazy in some of my ponds, requiring UV lights that I did not use before the city started this massive local phosphate addition (in our case to kill mussels). If you are having unexplainable algae problems in the Summer, you may want to measure the phosphate in your tap water.

A very long list of acidic and basic materials can be added to adjust the pH of drinking water. Our local water varies in pH from 4 to 8 through the year, for example.

Additives legal to increase pH are:

sodium bicarbonate or baking soda up to 150 ppm

calcium hydroxide up to 650 ppm

calcium oxide or quick lime up to 500 ppm

Sodium hydroxide

Additives allowed to drop pH include:

Carbon dioxide up to 100 ppm

ferrous sulfate or ferric sulfate up to 100 ppm (pH of 4 material)

sulfuric acid up to 50 ppm

phosphoric acid to adjust pH and prevent pipe corrosion

Also, activated carbon can be added to absorb impurities up to 150 ppm activated carbon content.

Questions?

[MikeM]

Other than chlorine/chloramine, and phosphates affecting algal growth, it seems all of these would harmless to the extent the pH was otherwise appropriate. Or, am I missing something??

[Roddy Conrad]

You are not missing anything.

I went through the entire approved water additives list carefully to check it out, did not see any real problems other than the possibility that chlorine/chloramine levels can be higher than assumed by dechlorinator dosing practices. And, as discussed earlier in the thread, that would only create a problem in a very clean pond, since a "normal dirty" pond would immediately "eat" the chlorine or chloramine.

[MikeM]

Roddy: What info do you have on decomposition rates of ST?? Is excess still going to be around in 24 hrs after application to typical koi pond?

[Mike T]

Interesting posts: One question; I haven't seen any mention of filtration via a product like All Clear Water Purifiers from the UK whereby a cartridge system, specifically designed for Aquatic life to include Koi, is hooked up to a water source to purify the water before it enters the pond...Is there a reason for this?

Thanks in advance for your comments. Aloha! Mike