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Edited TWP Recharge Instructions

Editor's note:  Use these instructions at your own risk.   The chemicals used in this procedure are very dangerous and must be used with a great deal of caution.  It is recommended that you wear protective gloves and goggles when performing the following procedure.

Materials required:

  • 12 ounce can of Red Devil Pure Lye (good for 2-3 recharges) ~$2
  • One gallon Muriatic acid (good for about 20 recharges) ~$3
  • Turkey baster
  • Plastic container, 1/2 gallon or so... a deep bowl will work
  • Plastic bottle - needs to be fairly tough.  Use one that holds atleast  12 fluid ounces, marked measurements are a bonus
  • Measuring cup, 24 fluid ounce or larger
  • Glass or plastic stirring rod
  • About 5 gallons DI water (tap water will suffice) for rinsing resins
  • 5 gallon bucket
  • Activated filter carbon
  • Rubber gloves/goggles, just in case

Mixing the chemicals:

The Red Devil lye is sodium hydroxide (NaOH), the base that recharges the anion (brown) resin.  The lye creates a lot of heat when mixed, so fill a bucket full of cold tap water, even ice water.  Put 9 fl. ounces water in the plastic bottle.  Measure out 3 fl. ounces of the granular lye in the measuring cup, add this to the plastic bottle.  Cap the bottle and place it in the bucket of cold water, shaking occasionally to mix the solution.  After the bottle has cooled for a bit, add water to the bottle until it is at 12 fl. ounces.  Shake again, and keep it in the bucket until it has completely mixed and cooled. 

While the lye solution is cooling, mix 6 ounces of Muriatic acid (HCl)with 6 ounces of water.  Keep a window open or a fan going, as some chlorine gas will come out of the solution.  Add the acid to the water in case of splashing.  Set this aside for now.

The first obstacle is separating the resins.  Take the top off of the TWP, remove the carbon, poly pads and spring, then take the hose from the bottom and set it to drain into the bucket.  You may want to remove some of the resin - spoon some out so that there's about an 1" between the top of the resin and the top of the canister.  Lower the water level inside the TWP to about halfway down the DI resin.  Add about half of the lye solution slowly, and stir gently with a stirring rod.  Make sure the TWP is not draining during this time.  The lye solution will completely exhaust the cation (green/blue) resin, causing it to sink.  It will also cause the anion resin to float.  Add more lye solution until the two resins are separated, there will be a gap between them.  If needed, drain out a small amount of the water.  Use your turkey baster to remove the brown (anion) resin and place it in a container.  Remove as much as you can while leaving the exhausted blue (cation) resin behind.  If you removed some resin to start with, add it in now, separate the resins and remove it.  Add the rest of the lye solution to the container with the brown resin in it.  There should be enough liquid in the container for the resin to float.  Stir the resin occasionally.

Now take the hose from the bottom of the TWP, and drain the water from the TWP.  Run atleast a gallon of water into the TWP from the top, and drain it out in this manner to rinse the resin.  Drain the water level in the TWP down to the top of the carbon.  Now add the acid solution to the TWP.  Stir the resin gently without disturbing the carbon beneath it.  Let this sit for up to an hour, stirring occasionally.  The resin should start to change color from dark blue to a bright green.  Stir it until it is completely bright green again, which would indicated that the cation resin is completely recharged.  At this point, drain the TWP and rinse the resin with a couple gallons of water.  Put all of the water drained from the TWP into the waste bucket.  The acid is supposed to score the carbon and make it reusable, but I remove mine to keep junk from getting back into the filter.  You'll probably need to remove the green cation resin from the TWP and store it while removing the carbon.  Mark how high the carbon went up the TWP tube, and refill with new carbon to that height (or even a little higher) after rinsing out the TWP.  Rinse any poly pads or carbon pads, and put them back on top of the carbon.  Then put the green resin back into the TWP.

After the brown anion resin has had about an hour to recharge it is ready to be rinsed.  Stir it again.  Use the turkey baster to remove all of the liquid from beneath the resin in the container.  Add new water to the container, stir the resin, and remove the water.  Repeat this process using 1-2 gallons of water.  Put all of the water used for rinsing into the waste bucket.  After the final rinse, remove as much water as possible from the container, then add the brown resin back into the TWP, and cover it with the poly pads or carbon pads.  The resins may occupy a smaller volume at first, so be sure to keep the spring that comes with the TWP.  At this point, hook up the TWP as you would normally use it, and run a gallon or so through it, to go into the waste bucket.  After that, run a few more gallons through it, which can drain directly into the sink.

The water in the waste bucket should now be neutralized.  You'll probably notice the water in the bucket turn cloudy and yellow.  After a half hour or so, most of the junk should settle out on the bottom of the bucket.  At this point in the recharging process, you'll want to take a good look at the junk and say: "Thank God I Filter My Tap Water"  ;-)

You should now be able to drain this without any negative consequences.

Expect it to take around 2 hours the first time.  Subsequent recharges will take less time as you will know the procedure and the resins will already  be separated.  If you know people who are tossing out exhausted TWP cartridges, ask them to save them for you so you can recharge them and stockpile DI resins.  DI resin costs around $60 per gallon, so save up as much as you can especially when it's free :-)  You should have a minimum of two cartridges before recharging, as you will lose just a little bit of resin each time you recharge (it tends to stick to stuff).  Recharge the resins again when about one half of the cation resin has turned blue.

This product is a heavily edited rendition of Gary V. Deutschmann's TWP Recharge Kit instructions. 

Created by liquid
Last modified 2006-11-25 18:30