Backyard Aquaponics
A place to discuss aquaponics

Simple and dumb question, see above. Thanks for any inputs!

I am not sure. There is a whole line of filters to remove chlorine for ice makers. If the chlorine gassed off from freezing then there would be no marked for ice maker chlorine removing filters...

Personally i would say yes it does.

i dont think water can hold gas to any appreciable amount when frozen and Hypochlorous acid does not have any melting or boiling point listed, it rapidly reverts back to chlorine.

but i do not know for certain.

Play the AP scientist! take a chlorine ppm reading of tap water and then freeze it. then thaw it and repeat!

Dan brings up a valid point. If indeed the ice does release the chlorine then maybe the filters are there to prevent detectable amounts of chlorine gas from being formed in large volume ice makers? OH&S ?

Yep, I'm wondering if they can get trapped in bubbles in the ice, like how they measure CO2 in ancient ice cores...

I don't have a test kit for chlorine!

probably could get trapped in ice but not sure how easily it would be re-absorbed.

why do you ask?

PS, i dont have a Cl test either

Curiosity, and because I hate buying dechlorinator. I had to get some yesterday because the top-off water wasn't ready after several days (still smelled like a swimming pool), and the system needed topped up really badly. Saw on the bottle after I used it that it says not for food fish, amybe because of the allantoin? The slow outgassing may be because the water is cold or because the water dept put more in than usual. If I had cold water fish maybe it would be quicker in the Winter to just leave the water out in the cold to freeze in a day or two and use it as a block of ice. Or, get ice cubes from the fridge instead of waiting for the tap water to outgas.

On the flipside, would hot tap water be free of chlorine, or maybe have much less than cold tap water? My guess is that it would have less than cold water, and would also be faster to outgas fully.

Hot water would out gas more quickly but would still have the same amount to begin with.
Use ascorbic acid (vitamin C) to remove chlorine from your water. I don't know if it is any less expensive than aquarium dechlorinator or not but it is safe for the fish.
We use it to dechlorinate water mains that have been super-chlorinated prior to being put into service, if the water is going to drain into a creek or river.

That sounds cool BF, and I wouldn't hesitate to add something like that to the water. Where is a good source for it?

Sounds like a good chemical to use for AP if it can be sourced easily/inexpensively. Sodium ascorbate has a pH of 7.8 versus ascorbic acid at 3:

http://www.ilikewater.com/

Amazon and other places have it as a nutritional supplement:

http://www.amazon.com/Sodium-Ascorbate- ... B000JN8GFY

Wonder what the dose would be for 10 gallons of tap water?

Depends on how strong the chlorine in the water is. It does not take very much to nuetralize the chlorine and it does it very quickly.

The tablets we use for dechlorinization are brand name Vita-D-Chlor a large pail of 140 tablets runs about 250.00 a pail. Or about 10.00 a pound.

Calculations for use:
G = Gallons of chlorinated water
P = Part per million of chlorine

GP/100 = Total Vita-D-Chlor™ needed in grams
GP/45,400 = Total Vita-D-Chlor™ needed in pounds

If you have 3ppm chlorine in 1000 gallons of water you will need about 30 grams of sodium ascorbate or ascorbic acid to nuetralize the chlorine. 3ppm is pretty standard for US municipal water systems.

Two pounds (approximately one kilogram) of Vita-D-Chlor™ will neutralize 1 ppm chlorine in 100,000 gallons of water

GP/100= ascorbic acid in grams

10gallons x 3ppm/ 100 = .3 grams ascorbic acid

In other words not much and at that quantity I don't think it will effect the DO or PH very much.

Awesome, it sounds like a big bottle of nutritional supplement sodium ascorbate would be plenty.

I've been adding baking soda to buffer my water - would sodium ascorbate buffer as well? Maybe adding the sodium ascorbate for top-off water would wipe out the chlorine and buffer the water?

I guess it depends on how hard your water is and how much you add to the water, but ounce for ounce I imagine it would have about the same effect.
What I don't know is what is the difference in dissolved oxygen would be.

I think the chlorine gases off a bit, but it seems to depend on how long the ice takes to freeze.
We use a 15L insulated keg on the kitchen bench each day. I freeze water in ice-cream containers to make large blocks. These blocks don't seem to add a big taste of chlorine to the water, but if I use the little ice blocks made in the trays of the freezer, there is a stronger taste of chlorine.
Did that all make sense? Maybe if you are making bigger blocks that take longer to freeze the Cl has more time to gas off.

I add about 25 litres of tap water a day to my bathtub system, and have not used dechlor since the start.....

I use dechlor in the aquarium when doing water changes and have lost fish - never lost any fish in the bathtub.

edit - sorry probably a bit off topic

I have hauled quite a few fish in the US and I have been told not to use store bought Ice (as opposed to well water ice) to cool down the water. The reason,I was told, is the chlorine that remains in the ice will indeed kill the fish.

I would think it would take alot of 'chlorine ice' to cause a kill, but never have risked it.