Return to the Garden Experiments Forum | Post a Follow-Up

Water dechlorinator experiment

Posted by Dchall_San_Antonio 8 San Antonio (My Page) on
Sun, Jun 6, 04 at 19:17

Someone asked me to repost this from years gone by...

This is more of an experiment for me than a necessity. I've read that the chlorine in tap water can kill off the beneficial microbes on the surface of the soil. I know that a 1 inch rainstorm does my grass 10 times more good than when I water an inch, so maybe chlorine is the reason.

I checked into prices and found charcoal filled dechlorinators for about $30 and not rechargeable. They looked to be about 15 inches long and 1.5 inches in outer diameter. They connect to the faucet at one end and the hose connects to the unit at the other end. So it is basically an inline filter.

Before embarking on this project, I conducted a scientific analysis of the parts I had in my garage. I found I had PVC pipe in various diameters, PVC cement, and nothing else of value. I settled on 2-inch pipe for the project. I wanted something that would hold about two cups of activated charcoal and Zeolite (from kitty litter) to soak up the chlorine. So I made a few calculations and discovered that a 2-inch pipe just under 14 inches long would hold two cups. That sounded about right. Another reason for using 2-inch diameter pipe is that the volume calculation (length x pi x radius squared) for a one inch radius tube is a lot easier than any of the other pipe sizes I had on hand!!

Here's the parts list in left-to-right order of assembly...

One female hose thread to 3/4-inch male pipe thread adaptor
One 3/4-inch female threaded to 2-inch smooth male pipe adaptor.
One 2-inch female smooth to 2-inch male threaded pipe adaptor.
One 2-inch female threaded to 2-inch female smooth pipe adaptor
One 2-inch diameter pipe, six inches long.
One 2-inch female smooth to 2-inch female smooth pipe adaptor.
One 2-inch male smooth to 3/4-inch female threaded pipe adaptor.
One 3/4-inch male to male nipple.

Total cost so far is $7.47.

1.75 cups of activated charcoal (I used Sta-Green Professional Charcoal from the garden center at Lowes)
1/2 cup of generic kitty litter with zeolite (read the label looking for Zeolite). Got that at HEB grocery store - store brand kitty litter.
One Scotch Brite Heavy Duty Scour Pad cut into three 2-inch diameter disks.

Cost for these was $8. Total cost for parts is about $16. If you went to buy a dechlorinator, they're about $30 so, so far I'm ahead. Furthermore, I have enough charcoal and kitty litter to refill this thing at least 5 more times. I also have two extra scour pads.

Assembly was done with PVC glue and Teflon tape for the threaded parts. Cut the scour pad into circular disks that fit snugly inside the 2-inch tube. These are to keep the filter materials inside. After the parts are glued together, put one disk inside at each end and save one for when assembling the 2-inch threaded parts to keep the stuff from dumping out of the one you turn over before screwing it together. Fill each side of the tube with the kitty litter and charcoal and put the third scour pad disk on top of whichever side you decide to turn upside down. All this does is keep the charcoal from dumping out. I don't mean to be redundant with this paragraph but I'm still not sure I said that in the clearest way.

Then screw it back together and you're off to the dechlorinated races. I figure (without any justification) that it will last a year before needing to be recharged with a couple more cups of charcoal and kitty litter. The overall finished length is 15 inches. Finished weight with water is probably 3 pounds. This baby is heavy enough that it needs to lay on the ground, not hang from a faucet.

Note: I realize that the pipe threaded nipple is not a perfect match for the hose thread I used, but it's so close that it really wasn't worth the extra cost of the true 3/4 inch pipe thread to hose thread nipple.

I'm not convinced the charcoal I got is "activated." I'll do a test with colored water sometime soon. If it is activated, it should remove food coloring in one pass.

So for $16 and a little work, I have a rechargeable garden dechlorinator.

Follow-Up Postings:

RE: Water dechlorinator experiment

Thanks for the follow up

RE: Water dechlorinator experiment

Not to be a pain but do you think using PVC will provide interference as the "C" in "PVC" is chloride?

RE: Water dechlorinator experiment

chlorine in water tends to evaporate within hours of initial air exposure so all you need to do is to set out water in a barrel and allow it to breath or if you wish get a fountain that helps to accelerate the chemical evaporation.

RE: Water dechlorinator experiment

I was wondering if the high spray of a typical fan watering sprinkler is enough to liberate the chlorine out of the water as it goes into the air and comes back down. it's a fountain principle, right?
any one know if barbecue charcoal, smashed up into powder, is activated charcoal? if it isn't treated with 'instant lighting' chemicals, would it be clean for the purpose?

RE: Water dechlorinator experiment

This thread caught my interest tonight. I plan to set up a rain barrel really soon, it just isn't practical for me to use to water my lawn. Can you tell if the pipe invention is working to remove the chlorine from your water?


RE: Water dechlorinator experiment

"any one know if barbecue charcoal, smashed up into powder, is activated charcoal?"

Activated charcoal is wood burned without oxygen. Generally baked in a commercial oven. The byproducts are methanol, etc.

I don't think your average barbacue charcoal is activated charcoal, but I understand you can buy the real thing for aquarium supplies.

RE: Water dechlorinator experiment

Check to make sure your water really has chlorine and not chloramine. The first will evaporate if left out, the second will not. Also, not entirely sure if a filter would get the second out either, as it is bonded somehow to the water, is my understanding. You might want to look into that.

I had a freind who used to leave all water for houseplants out overnight before watering, then found out she had chloramine instead of chlorine and that all her effort had been useless.

The folks on the watergardening forum know quite a lot about chloramine, as it also kills fish. You might ask them about if it can be filtered. Most fish owners buy a bottle of stuff that gets rid of the chloramine.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Garden Experiments Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here