Starting Over

[SeaTurtle]

Hi

I'm new to this forum/community, new to a rented house with pool, new to BBB method but not new to DIY pool maintenance. The assessment after moving into this house and testing the pool water with TF-100 Test Kit is that it needs to be drained and refilled. It's a swamp, the water is about 4 years old, and the previous tenants said that the water will no longer hold chlorine.

Test Results:
pH: 7.5
TC: 0
Alk: 160
CYA: half way to the 100 line

Question: After refilling pool, what is the best way/best order to add new chemicals based on the BBB method?

 

[duraleigh]

After refilling pool, what is the best way/best order to add new chemicals based on the BBB method?

Probably the best thing you can do after refilling is to test again and post those results. They will be different.

Next, read "The ABC's of Pool Water Chemistry" up in Pool School. Gain an understanding of what you are testing and what to do with your test results.

Upon refilling, adjusting pH (if it needs it) and then adding chlorine will be the two most important things

 

[SeaTurtle]

wow, what a quick reply! thank you! I've read the ABC's, and just wanted to know if there was a recommended way to get things going again from scratch. I'll post the test results after refilling and start with the pH and chlorine as suggested. By the way, your test kit is AWESOME.

 

[duraleigh]

Thank you!

A general guideline (but don't put this in the bank until you post your results)...

1. Adjust pH to mid 7's if necessary.

2. Add enough chlorine in the evening to get to 2-3 ppm

3. Add enough CYA to get to 20-30ppm

4. Plan on shocking the pool at this point but that depends on your results and some other things

5. Adjust CH and TA if needed.

6. bring CYA up further.

 

[SeaTurtle]

Excellent, thanks again.

 

[harleysilo]

I'm just curious, I don't understand why water replacement is necessary? I understand it may be preferable to drain a swamp versus clearing it with a bunch of bleach.

What is your current CH level?
So CYA is 50ish? Which should be just fine.

"Won't hold chlorine" sounds like a bunch of hogwash.

What don't I understand?

 

[Smykowski]

"Won't hold chlorine" sounds like a bunch of hogwash.

What don't I understand?

Nope, you're exactly right. The previous owners dodn't understand that chlorine is consumable. If there's algae in the pool, FC disappears because it's doing its job. Hence the idea that the water must be old and must be replaced. Since we all understand the chemistry, we know exactly what's going on. (What's the quote: All technology, if significantly advanced enough, is indistinguishable from magic.)

In this case, water replacement will be required, but because of the high CYA levels, not because the water is old. (I'm reading "CYA is halfway to the 100 line" as CYA is greater than 100.)

 

[SeaTurtle]

The two factors I'm basing water replacement on are these:

1. The previous tenants reported that they worked with a pool service that recommended water replacement because they only way they could keep a chemical balance in the water was to use/waste tons of chlorine (because it disappeared so rapidly). This is what they meant by "won't hold chlorine."

2. Smykowski is correct, the CYA is over 100 which, as I understand, is why they had to use so much chlorine, and which needs to be lowered by water replacement.

 

[harleysilo]

Ah! Carry on then!

 

[Mike_k]

Ah! Carry on then!

Just to be clear... carry on because of #2 above (CYA). Water doesn't wear out and lose its ability to hold chlorine.

 

[SeaTurtle]

ok, pool is drained and refilled. Test results of new water are as follows:

pH: 7.8
TC: 0
TA: 190
CH: 200
CYA: 0

 

[SeaTurtle]

so at 11:30am I added 35 oz of muriatic acid and 100oz of 8.25% bleach and left the pump on. I got home at 6pm, the pH is down to 7.5 but my TC is still 0. I'm assuming that's because I didn't add any CYA yet and the Arizona sun ate up the chlorine.

 

[Richard320]

so at 11:30am I added 35 oz of muriatic acid and 100oz of 8.25% bleach and left the pump on. I got home at 6pm, the pH is down to 7.5 but my TC is still 0. I'm assuming that's because I didn't add any CYA yet and the Arizona sun ate up the chlorine.

That is likely. Also, you might have some organics in the plumbing and filter that the chlorine is eradicating.

 

[SeaTurtle]

ahhh good point. I'll plan to add the CYA and more bleach tonight.

 

[dafuzz]

You may want to build an aerator to assist you in getting your TA down too.

http://www.troublefreepool.com/pool-school/lowering total alkalinity

 

[duraleigh]

Thanks for those test results.

It seems to work well to adjust TA last. I would suggest you get all your other parameters where they need to be (as you are doing) and then run for a week or so before addressing TA.

 

[SeaTurtle]

will do. I've got two nylon sacks of CYA in now, 2lbs each, one in the skimmer and one in front of a return. Chlorine levels are finally coming up

 

[SeaTurtle]

duraleigh, you mentioned that I might want to shock the pool once I got TC to 3ppm and CYA to 20ppm. Is that still your advice? My current readings this morning:

pH: 7.5
TC: 3
TA: 190
CH: 180
CYA: 20

 

[Richard320]

duraleigh, you mentioned that I might want to shock the pool once I got TC to 3ppm and CYA to 20ppm. Is that still your advice? My current readings this morning:

pH: 7.5
TC: 3
TA: 190
CH: 180
CYA: 20

Have you used the FAS-DPD chlorine test yet? That's the one with the powder.

That will tell you within .2 (25 ml sample) or .5 (10 ml sample) what FC and CC are.

Armed with the facts, you'll know what to do next.

Remember, the goal here is not to have perfect numbers - nobody but a few of us here care about that - but to have super clear sparkly water. Fresh fill, clear water, no CC, shocking may be a waste of bleach. On the other hand, if the water is clear but just a little hazy, stop the algae in its tracks.

If unsure, hit it hard with bleach. You're only out a couple bucks if it didn't need it, and many bucks ahead if you stopped it in time.

 

[JohnN]

Just to add to what Richard said, the 10 ml sample is accurate enough. No need for .2 ppm accuracy.