Pool chemistry in balance but cloudy and slightly green

[JaxHomeOwner]

Hello all,

My wife and I have recently moved into a new house. The pool was originally Baquacil, but we switched over to chlorine after a neon green algae outbreak. The switch went fine and we were able to swim for the rest of the summer (we bought in June and switched in August). Recently, we have not been swimming because it has been too cool. The pool is now cloudy with a green tinge to it. We have tried vacuuming and we have been measuring the water chemistry. The pool is 21,000 gallons in ground and the water chemistry is as follows:

FC - 9
CC - 0
CYA - 60
TA - 100
pH - 7.6

We have tried to maintain the chlorine levels lower than 9, but shocked when the algae started and the FC never came down. I had a few questions: Should you shock as soon as you see any green starting to come up? If no one is swimming, can this lead to the green color even if the pump is running 9 hrs/day? The water level was too high, and I recently drained the level so it came up to halfway on the skimmer opening, could this have played a part? Should I shock right now? The CC has not been registering for the past week, and our FC levels have been steady around 9 (or higher). It has not really rained here recently, but has been slightly overcast and chilly. I appreciate any help at all!

 

[linen]

Welcome to tfp, JaxHomeOwner

Green and cloudy is almost always algae. I would do the SLAM process: http://www.troublefreepool.com/pool-school/shocking_your_pool and start by doing an Overnight Chlorine Loss test (OCLT) as described in the link in the SLAM process pool school article.

Should you shock as soon as you see any green starting to come up?

Generally yes.

If no one is swimming, can this lead to the green color even if the pump is running 9 hrs/day?

No

The water level was too high, and I recently drained the level so it came up to halfway on the skimmer opening, could this have played a part?

No

Should I shock right now?

I would

One question for you, did you follow the tfp baquacil to chlorine conversion process?

 

[JaxHomeOwner]

We did follow the routine either listed here or on the pool forum. We kept the chlorine levels at 15 ppm, and waited until the oclt was less than 1, and our CC was <0.5. Our pump ran 24hrs/day and we washed the filter daily due to it being old and the pressure going up rather quickly. After the process was complete, we ordered a brand new filter. I am going to shock tonight and keep the pump running. I will post back the results we get. Thanks for the quick reply!

 

[jblizzle]

You need to SLAM ... not sure what shock means around here

 

[JaxHomeOwner]

I had to go to the link you posted to figure out what "SLAM" meant. I raised the FC level and will test the water first thing tomorrow morning. If I may, when did the term "shock" fall out of vogue? We never had a pool growing up by my neighbors did and they shocked their pool.

On a side note, I was also wondering if adding baking soda raises the pH AND increases alkalinity?
On the flip, does adding acid lower pH AND the alkalinity?

Thanks, you guys and gals are life savers!

 

[linen]

We used to call the "SLAM process" the "shock process" but too many people confused that with a one time dose of chlorine and not a process of raising and holding the chlorine level at the appropriate high FC level until all three criteria in the "SLAM process" are met simultaneously.

 

[linen]

On a side note, I was also wondering if adding baking soda raises the pH AND increases alkalinity?
On the flip, does adding acid lower pH AND the alkalinity?

Generally, baking soda is only used to raise TA as it typically has little effect on ph. Using Muriatic acid lowers both ph and TA. See this pool school article: http://www.troublefreepool.com/pool-school/recommended_pool_chemicals

 

[jblizzle]

The fact that you had to go to the link to read what the SLAM process is ... That is exactly why we changed the term.

"Shock" just means too many different things to too many different people.

 

[JaxHomeOwner]

I measured the chlorine this morning. I added enough liquid chlorine last night to bring the levels up to about 26 (a little higher than the shock level for my CYA levels). This mroning the FC was 25.5 and the combined chlorine was 0.5. The pool was still cloudy and a little green. This afternoon when I get home from work I will test again and brush/vacuum the pool. My wife and I found out today that our electric bill was through the roof from running the pump and trying to vacuum/brush and get rid of the algae. We thought we were OK because the FC was at 9 ppm, a little high even for our CYA levels.

Is there a best time to run the pump, day or night, that is optimal to prevent algae? The other thing I am confused about is that our FC was high, CC was extremely low, how is it that we can still get cloudy water and a green tinge if all of our values our in line, albeit a little high?

 

[jblizzle]

It does not really matter when you run the pump. Although during the SLAM process it should be on 24/7.

If the FC ever dipped below the minimum required for your CYA, then algae can start to grow. Once it starts, you need to follow the SLAM process to eradicate it. CC have nothing to do with the presence of algae.