Time to replace sand?

[PoolDoc]

The ingredient you listed is a mix of EDTA (a chelant) and ammonium sulfate. Adding ammonia according to the instructions you followed produces monochloramine. MonoC is very effective against algae, but also rather irritating. It's going to take a LOT of chlorine to get rid of it.

Also, you have very high TA due to the soda ash (borax would have been a better choice to use with the "G to C", but I'm sure the store didn't tell you that!). And it looks like you've done a bit of lime softening (lowered CH), which means some of the cloudiness is probably calcium carbonate.

So . . . you need dose with 6 gallons of bleach each evening. Take a break if you have higher than 15 ppm the following evening. Continue to dose that way till your CC is below 1 ppm, and your chlorine levels will 'hold' overnight.

Also, you'll need to get that TA down. So use muriatic acid (gloves, glasses, pour close to the water, watch the fumes!) to lower the pH till you reach 6.8. Stop, and wait for the pH to climb above 7.0, then repeat. Continue till your TA is below 100 ppm. The process will go faster if you adjust your return eyeballs so they 'ruffle' the water's surface.

Once you get done with those two things, you can decide whether you want to drain and refill, or run high chlorine. Personally, I'd run high chlorine.

Good luck!

Ben

[jonno]

The pool failed the overnight test. This morning FC = 0.5 TC = 5.5, pH = 7.2, TA = 190.
Thanks for the information about lowering the TA Ben. My return is ruffling the surface and I'll pick up some muriactic acid today. I'll also stock up on bleach.

Ben - can you clarify your instructions:
1. Add 6 gallons of bleach nightly until I get 15ppm the next evening - is that FC or TC?
2. Continue that way until the CC is below 1ppm - does that mean that FC and TC should be within 1 ppm of each other?
3. Get that TA down with muriatic acid until pH is 6.8. Wait for pH to climb above 7.0, then add another dose of muriatic acid - how long should i wait between tests? how much muriatic acid should I add for each dose? 1 cup for a 26K gal pool? Follow instructions on muriatic acid container?

Watermom (and Janet) - the priority in your instructions seems to be to get the chlorine to 25 and keep it there. The 17 gallons of bleach I added last night only got the FC to 4.0 and this morning it has dropped to 0.5. Here are my questions on your instructions:
1. You advised me to test as many times a day as possible and bring the cl back up to 25 each time (so the FC = 25 right?). I'll add another 17 gallons this morning, but how long should I wait after adding the bleach to see if I've reached 25? If not, I should add more bleach immediately - right?
2. You said to keep pH above 7.2, but Ben says to follow the steps lower the TA - should I do that now or wait until the FC passes the overnight test by holding within 1ppm of 25?

[Watermom]

1. FC
2. Yes.
3. I would try a pint of muriatic acid at a time. Wait a couple of hours, then retest pH and see how far it moved. If not low enough, add another pint and repeat.

1. Follow Ben's bleach dosing instructions instead.
2. Follow Ben's directions to lower alk.

You can read more about lowering alk here:

http://www.poolsolutions.com/gd/lowe...p-by-step.html

[jonno]

Thanks. I think I've got it. Here's the plan:

Get the TA down with muriatic acid until pH is 6.8.

1. Add 1 pint of muriatic acid, wait 2 hours and retest pH. If not 6.8, add another pint of muriatic acid, wait 2 hrs, etc.
2. Continue to aerate as this will lower the TA and raise the pH.
3. Keep testing pH and TA. Maintain pH at 6.8 (adding 1 cup to 1 pint of muriatic acid as needed).
4. Once TA reaches 120 (currently 190), let pH increase to normal level (7.4-7.6). If this does not happen within a couple days, add small amounts of borax to bring it up.
5. Once TA = 120 and pH is 7.4-7.6, stop aerating.

While lowering the TA, test FC and TC nightly.

1. Add 6 gallons of bleach nightly.
2. If FC = 15ppm from the previous night’s dose, skip the bleach for until the next evening.
3. Repeat this nightly until the CC is below 1ppm (FC and TC are within 1 ppm of each other)

Couple more questions:

• Am I missing anything in the steps above?
• Should I wait at least two hours after adding muriatic acid before adding the nightly dose of bleach?
• For my 26K gallon vinyl IG pool, how much is "a small amount" of borax? 1lb?

Thanks for the support, instructions and education! This morning I could just make out the second rung of the ladder so the visibilty is starting to improve. I'll keep you posted via this thread. -- John