pool balance before closing?

[CarlD]

Ouch! I'm not really that knowledgeable about masonry pools, so I guess I'd start with where you want to be. I'm guessing here and corrections by those who are more familiar would be welcome.

Start by testing your fill water BEFORE you fill the pool so you know what's in it and where you're starting.

FC: Depends on your CYA level, but initially, until you reach a CYA of 30 you'd want it to be between 2 and 5ppm.
CC: Try to keep at zero
pH: You'll want to keep it in the standard 7.2-7.8 range. While your pool is curing expect it to rise so keep muriatic acid handy.
T/A: Your target for Total Alkalinity is 80-120ppm.
CH: Calcium Hardness or Hardness. Masonry pools require 200-400ppm
CYA: Stabilizer. We generally recommend a minimum of 30ppm, though higher can be manageable or desirable.

How to get there:
I'd always start with chlorine--keep anything from growing.
If you start with Cal-Hypo (get it at least at 56%, 65% is better) then you're adding chlorine and calcium at the same time. If your water is already hard and in the 200-400ppm range, don't use it. You'll get about 7-8ppm of CH for every 10ppm of chlorine.
If you start with Di-Chlor powder you're adding an initial dose of CYA with your chlorine, too. About 9ppm of CYA for every 10ppm of chlorine. It's slightly acidic.
If you start with Tri-chlor powder (don't see it much) or tablets, you're getting chlorine, CYA (6ppm for every 10ppm of Chlorine) and it's very acidic.
If you start with bleach/liquid chlorine you'll have to add CYA and possibly calcium flakes as well.

You cannot mix them together in a slurry because it's extremely dangerous. I think, though the most important things to control first are chlorine and pH, after that calcium and T/A, and finally CYA (which can take 48 hours to a week to get to the right level).

I cannot really advise you beyond this because I'm just guessing. But with most chems if you wait an hour or two before adding the next, you're OK.

A lot of it is preference. You may start with a dose of Cal-Hypo to get your FC up, then when it's dissolved fill a floater with Tri-Chlor pucks. Or you may start with Di-chlor, and then fill the floater with Trichlor, and a little later add calcium. Or you could start with bleach/LC, add calcium flakes and tie a stocking filled with CYA to the side of the pool to dissolve. All will work.

Just don't dump everything in at once.

[FNC1962]

Thank You!!!

[PoolDoc]

Test your FILL water (pH, TA, CH only) and post those results. I can then calculate doses -- once your pool is full -- to bring you into a safe range for winter.

If you have had problems in previous years with the pool being slimy on opening you may want to consider the additional steps of raising borates (> 60 ppm) and lowering phosphates (< 0.125 ppm) prior to closing. Alternatively, you can maintain intermittent chlorination while closed. I can help you pursue either or both.

[FormerBromineUser]

Great advice! As long as you're testing your fill water, maybe a metals bucket test on fill? Just a thought. Think there's a lot of Calcium in some parts of KY.

[FNC1962]

Test your FILL water (pH, TA, CH only) and post those results. I can then calculate doses -- once your pool is full -- to bring you into a safe range for winter.

If you have had problems in previous years with the pool being slimy on opening you may want to consider the additional steps of raising borates (> 60 ppm) and lowering phosphates (< 0.125 ppm) prior to closing. Alternatively, you can maintain intermittent chlorination while closed. I can help you pursue either or both.

PoolDoc, The pool is almost full. pH 7.0, TA 100, CH 150.

[FNC1962]

Test results for today are pH7.3, FC 2, cc 0, TA 90 , CYA<30,
Looking for suggestions on what to add and how much. Thanks
I will be putting a security cover on for winter.

[FormerBromineUser]

What is the chemical composition of your "skimmer tabs" ?
What other chemicals do you have on hand?

[FNC1962]

Bio-gard 3" basic chlorine tabs (99% trichloro-s-triazinetrione) 90% available chlorine, Bleach, Borax, Baking soda and muriatic acid is what I have on hand.

[FormerBromineUser]

Test your FILL water (pH, TA, CH only) and post those results. I can then calculate doses -- once your pool is full -- to bring you into a safe range for winter.

Okay, we have fill results and current pool water results. I am still thinking that with a new finish that you may need to raise that CH of 160 up to >200. Anyone agree?

[PoolDoc]

Sorry it's taken me so long to reply.

Assuming: 17k gal, pH: 7.1, TA: 90, CH: 160, CYA: ~20. Location in KY, with moderately cold winter (sub-zero possible, but not likely).

One open question: is the "security cover" mesh or opaque?

Comments:

Your current water is unlikely to scale, but could possibly damage the concrete bottom. However, adding lots of calcium will increase the chance of algae-aided calcium deposits. So . . .

1. Raise your borax to 60 ppm -- 11 boxes of borax. Do NOT add acid at this time. Borax will significantly reduce the chance of algae forming under the cover, and will make it easier to kill the algae if it does form.

2. Target a pH level of 7.8 - 8.0. This will reduce any corrosion of the concrete to vanishingly small levels. The borax addition may be sufficient to raise the pH, or you may go a bit high. But WAIT till it's fully dissolved before attempting to adjust the pH either way.

3. If you are not using the pool, go ahead and install the cover now. If it's a solid cover, leave a corner uncovered so chlorination byproduct gases do not accumulate.

4. Use bleach to raise the chlorine levels UNDER the cover, and eradicate any remaining algae.

5. Test chlorine & pH, but don't bother with other tests until the pH is back in range.

6. Report back once the borax is up, the cover is on, the pH tested, and the algae is gone.