I do have the directions. Thank you Peggy! I didn't realize chlorine dissipated after 3-24 hours.
It doesn't! I have no idea what directions you're following, but they aren't the ones in my book (which your photo indicates you have, although it's not the current revised and updated edition, which you might consider getting.)
This is what you should be doing (same directions that are in both editions of my book):
Although most people think only in terms of the tank, the plumbing is actually the source of most foul water, because the molds, mildew, fungi and bacteria which cause it thrive in damp dark places, not under water. There are all kinds of products sold that claim to keep onboard water fresh, but all that’s really necessary is an annual or in especially warm climates, semi-annual recommissioning of the entire system—tank and plumbing. The following recommendations conform to section 10.8 in the A-1 192 code covering electrical, plumbing, and heating of recreational vehicles. The solution is approved and recommended by competent health officials. It may be used in a new system a used one that has not been used for a period of time, or one that may have been contaminated.
Before beginning, turn off hot water heater at the breaker; do not turn it on again until the entire recommissioning is complete. Icemakers should be left running to allow cleaning out of the water feed line; however the first two buckets of ice—the bucket generated during recommissioning and the first bucketful afterward--should be discarded…bleach does absolutely nothing to improve the flavor of good Scotch!
1. Prepare a chlorine solution using one gallon of water and 1/2 cup (4 oz or 25 ml) Clorox or Purex household bleach (5% sodium Hypochlorite solution ). With tank empty, pour chlorine solution into tank. Use one gallon of solution for each 5 gallons of tank capacity. (Those are the “official” directions. They work out to 1 quart or litre of bleach/50 gallons of water tank capacity , which is MUCH easier to calculate!) I also recommend putting the solution into full buckets of water instead of pouring it into an empty tank.
2. Complete filling of tank with fresh water. Open each faucet and drain cock until air has been released and the entire system is filled. Do not turn off the pump; it must remain on to keep the system pressurized and the solution in the lines
3. Allow to stand for at least three hours, but no longer than 24 hours.
4 Drain through every faucet on the boat (and if you haven't done this in a while, it's a good idea to remove any diffusion screens from the faucets, because what's likely to come out will clog them). Fill the tank again with fresh water only, drain again through every faucet on the boat.
5. To remove excess chlorine taste or odor which might remain, prepare a solution of one quart white vinegar to five gallons water and allow this solution to agitate in tank for several days by vessel motion.
6. Drain tank again through every faucet, and flush the lines again by filing the tank 1/4-1/2 full and again flushing with clean water.
An annual recommissioning according to those directions should be all you need to do to have water that's at least as "good" as the water from any faucet on land. If that doesn't suit you, put a faucet filter on the galley sink. No need for any water "treatment "...nor should it be necessary to add anything to every fill. No wonder you're filtering it going into the tank AND at the galley faucet...you're putting enough chlorine into your water to make it taste/smell like a swimming pool! And yes, that will make bio-active holding tank maintenance difficult, if not impossible.
--Peggie
