Lime Softening to Reduce Excess Hardness - Bucket Test & Treatment Process

------- 2018 - Do NOT use this process without talking to me (PoolDoc) first --------

---------- If you are unable to reach me, try an alternative method! ----------

Doing a "Bucket Test" for Lime Softening

In a perfect world, you'd always know everything you need to know about your pool. And, you'd know when you added a pool chemical exactly what it would do.

But, this is not a perfect world, so it's often better to experiment with a little water, rather than a whole pool full. In water treatment plants that supply potable water, or treat sewage, chemical doses and other treatments are tested using "jar testing", using special large glass jars and mixers.

"Bucket tests" for pools can be done for 5 reasons:

1. Lime softening. Calcium levels (hardness) can get too high in pools. One way to lower hardness is to drain the pool and refill with softer water. But, this not only wastes water, it can destroy liner or fiberglass pools. Lime softening is a way of removing calcium, by adding soda ash, till the calcium in your pool clouds the pool or drops out, and then can be filtered or vacuumed out.
   
2. Chlorine demand testing. Often when pools have problems, it's hard to tell 'how much more chlorine' it will take to fix things. In particular, this is true when a pool is all slimed up with algae or bacterially generated ammonia. A chlorine demand bucket test can answer the question, how much chlorine will it take, to clean up my pool.
   
3. Leak testing. Pools that are in use lose water for 3 reasons: evaporation, swimmer splashout, and leaks. Especially in dry climates, it's hard to tell how much water is being lost to evaporation. One form of bucket testing can answer the question: "Is it a leak, or is it evaporation?"
   
4. Metals testing. Metals stain pools. Swimming pool water can get metals in it from many sources: algaecides, corroding heaters or pool parts, well water, water delivered by trucks, and so on. The problem is, many metal treatments HIDE the metals: they are STILL in the water, but they aren't showing up. Most tests for metals can't reliably detect sequested or chelated metals. But, a metals bucket test can answer the question, "Are there still metals in my pool water? What kind?"
   
5. Floc testing. Many pools suffer from the big pump / little filter problem. This isn't so bad, when all is well, but when their pool is cloudy from dead algae, or precipitated calcium, or added phosphate remover, it can be very hard to clean up. And, it can be hard to tell what well help. A floc bucket test can answer the question, "Will this floc help my pool, or mess it up worse?".

All bucket tests start the same way: with a bucket! White 5 gallon buckets like these from Lowes or this 10-pack from Home Depot are ideal.

You can get these at Amazon, but they are expensive there, so it makes sense to buy them locally, unless you are not near a large hardware or building suppy store. Used 5 gallon white pool chemical buckets are ideal -- if they are clean, and if you have any. A white mid-size trash can will work, too. But it HAS to be clean.

Otherwise each of the 5 bucket tests has different requirements.

To perform a lime softening test, you'll need the following:

1. A white 5 gallon bucket.
2. A 1 gallon or 1/2 gallon clean milk jug or orange juice container (to measure with).
3. A Taylor K-2006 test kit -- you will need most of the tests in that kit. (Test kit info page)
4. A jug of plain 6% household bleach.
5. A box of Arm & Hammer Washing Soda (from Walmart)
6. Lids or towels you can cover to cover the buckets.
7. A plastic or stainless steel tablespoon measure
8. A clean household long-handled stainless or plastic cooking spoon
9. The capability to vacuum to waste. <= This is CRITICAL!

To carry out the test:

1. Use the gallon or half gallon measure to collect pool water.
2. Fill the first white bucket with 4 gallons of POOL water.
   (Measure by adding 4 measured gallons OR by adding 33 lbs of water to the buckets).
3. Add 1 tablespoon of bleach, and mix.
4. Test your POOL water's hardness; round result up to nearest 100 ppm
5. Add 1 tablespoon of soda ash to bucket for each 100 ppm of hardness, plus one more tablespoon.
6. Mix thoroughly, and cover.
   (The water should turn very cloudy, after you add the soda ash. If it does not, ask us what's going on!)
7. Inspect after 24 hours, and again after 48 hours for settling.
8. If mixture does settle, test clear liquid from top for calcium hardness.
9. 10. Verify that sediment is a thin layer that can be vacuumed up.

If the hardness shows a SUBSTANTIAL drop (say, 600 ppm to 200, or 400 to 100) AND the sediment has quickly settled to the bottom, you are ready to proceed to treating your pool. Otherwise, ask us before proceeding.


Treating your pool to lower excessive hardness levels:

1. Before you start, make sure your pool is reasonable algae free.
2. Turn off ALL equipment: heaters, heat pumps, SWCGs, etc.
   If you can bypass them, do so.
3. Make 100% certain you are ready to "vacuum to waste".
   This is the only practical way to remove the sediment that will form. If you are unable to vacuum to waste, you may be 'stuck' with a messed up pool, and no way to clean it. PRACTICE vacuuming to waste BEFORE you add soda ash, just to make sure you can do it.
4. Make 100% sure you have the chemicals on hand that you will need.
   For each tablespoon used above, you will need to add 9 lbs of soda ash (2 1/2 boxes of A&H Washing Soda). For every 2 boxes of washing soda, purchase 1 gallon of muriatic acid. And purchase 1 quart of 60% polyquat for every 20,000 gallons, or portion.
5. Make 100% sure you have the refills you need for your K-2006, and won't run out during the process.
6. Clean your pump basket, skimmer basket, and filter.
7. Adjust all the eyeballs or returns in your pool so they point UP and away from the pool bottom.
8. Once you are fully prepared, proceed to treat your pool.
9. First, raise the water level to the maximum you can.
   (You're going to be draining quite a bit.)
10. Add the soda ash:

    + If you have a multiport valve, put the valve on recirculate and add via the skimmer. You should see clouds of calcium carbonate forming right away, where water returns to your pool. Continue adding soda as slowly to the skimmer, till it's gone. Wait 1 hour, and then turn your pump off.
    + If you have a cartridge filter with no multiport, remove your cartridge from your filter. Then, proceed as above.
    + If you have a DE filter with no multiport, do NOT add the soda ash to your skimmer. Instead, dissolve it in a bucket and pour the mixed solution into your pool. Once the soda ash has been added, proceed as above.

11. Wait 24 hours - 48 hours, to allow the precipate to settle.
12. Set up your vacuum, and vacuum the sediment to waste, either by siphon, or by turning your pump back on, with the multiport
13. As soon as most of the sediment is gone, put your multiport valve on recirculate, and begin adding acid. You can estimate the quantity required, by using the Acid Demand Test in the K-2006 test kit.
14. Add acid directly to the pool, so the acid enters the pool just above a return jet. You do not want the acid to hit the bottom of the pool, and dissolve any remaining sediment. Add acid in increments of 1/2 gallon per 10,000 gallons of pool water. Wait 30 minutes, and test the pH. If the pH is still above 8.0, add more acid. Continue till the pH reaches 8.0 or just below.
    (If you have the ADT -- you can add 1/2 of the calculated dose initially. Then retest, and add 1/2 of THAT dose, and so on, till you reach 7.8 - 8.0.)
15. If for some reason things go wrong, do NOT leave the pH high for longer than 72 hours. Go ahead and lower it even if the pool is still cloudy, or the sediment has not settled.
16. Once the pH is 7.8 - 8.0, add a dose of polyquat.
17. Wait 8 hours, and then restore your filter to normal operation. Vacuum any remaining sediment normally, and then clean your filter.
18. 24 hours after adding the polyquat, begin lowering your pH to 7.2 - 7.4.
19. Once you reach that pH level, test your hardness and alkalinity. Your hardness should be greatly reduced, but your alkalinity may (or may not) be way too high.
20. If your alkalinity is too high, add acid till your pH reaches 6.8 - 7.0. Then, read the alkalinity and follow those instructions till your alkalinity reaches an acceptable level.

Sources:
Purchase bleach and washing soda from Walmart.
Purchase the muriatic acid from Home Depot, Lowes, etc. Read this page on handling muriatic acid safely.
Read the test kit page for info on the K2006 and other kits.

Kem-Tek 60% polyquat @ Amazon
Nava 60% polyquat @ Amazon

Explanation:
Normally, the only way to lower your calcium hardness level is to drain and refill. This is a wasteful and expensive approach, and works very poorly when the water available to fill a pool is itself hard.

Lime softening is an old water treatment process, which turns the calcium hardness into what are essentially small particles of limestone, where they can settle to the bottom. The process works by (a) raising the pH and (b) adding carbonate alkalinity (=CO3) that can combine with the calcium to form lime. When this is done in pools, the sediment can be vacuumed OUT of the pool, leaving the pool much lower in calcium. In the process, metals and other contaminants are often removed as well, leaving a much higher quality of water behind.

Once the calcium is gone, the pool will still be at a high pH, and quite possibly high in alkalinity. However, adding acid will resolve the pH, and over time, lower the excess carbonate alkalinity by converting it to carbon dioxide gas.

The process is not particularly hard, but the order of events is critical. The steps above MUST be followed in the order given, or you will be left with a mess. Also, it's absolutely critical that you NOT try to blend in advice from your pool store. The pool industry is generally so ignorant of general water treatment methods that they will almost certainly screw things up, if you let them 'help'.

References on lime softening:

Wikipedia
GE Water Treatment Handbook
Minnesota Rural Water Assoc.

Lime softening calcs
1.1kg/liter => soda ash
1 liter = 33.8140227 US fluid ounces
1100gm/33.8 fl oz = 32.5gm/fl oz
Soda ash gm/mole: 105
soda ash 16.3 gm/tablespoon
Calcium carbonate gm/mole: 100
100 ppm hardness in 4 gallons => 33 lbs = 15,000 grams
100 ppm hardness in 15,000 grams = 15 grams
So . . . 1 tablespoon of soda ash = ~ 105 ppm soda ash OR 100 ppm alk as CaCO3