Little bitty bubbles

[Deb04]

I have little bitty bubbles on most of the walls of my vinyl pool. Wondering what they are from. When I brush they just rise to the top and pop. Thinking they may be as a result of algae?

Background: I know I have some algae right now. About two weeks ago we started a week of rainy, stormy weather and the solar cover was on for about a week straight. When the cover came off, the water was a little bit couldy. Not awful, but I could tell the difference from my normal crystal clear pool. I shocked until it met the 3 criteria. Got dead algae on the bottom of the pool.

On Wed we put the cover back on for the first time since shocking. Yesterday took the cover off and it was cloudy again. Not as bad as last week and I don't think that anyone besides me could tell. Because we are having guests all weekend, my plan is to keep the algae under control best as I can and then shock it starting Sunday night. Since I'm guessing that the reintroduction of algae came from the cover, I'm going to put the cover one while the water is at shock levels.

FC = 12
CC< 0.5
CYA = 40
ph= 7.4

Anyway, any idea what the little bubble are?

 

[y_not]

You don't list your TA. CH isn't a big deal since you have a vinyl pool, but it's important with a SWCG, so if you could test for that as well, that'd be helpful.

Don't worry about whether the others see the water change or not, you're the pool maintainer & are clearly now an official TFP Water Snob. I'm one too... CONGRATS!!!

I see in your sig that you're running a SWCG/SWG, but that your CYA is only 40ppm. That is much too low for a SWCG pool.
It should be between 60-80ppm, otherwise the SWCG isn't as effective due to CL loss from UV/outgassing and you can end up with algae blooms. Just as you have witnessed.

See the following article from PS on proper SWCG water balance: pool-school/water_balance_saltwater_generator
See this article for how to properly set your peak chlorine output and making sure your runtime & percentage output setting doesn't drop below recommended levels.
pool-school/salt_water_chlorine_generators

Pay special attention to CYA levels, pH & TA which is CRITICAL to keep your cell from scaling and shortening its life, as well as properly adjusting your SWCG so you don't run below the minimum between cycles.

Unless you are currently "shocking", your FC levels are much too high. Even for shocking, that's too low, as you should be at 16ppm FC for shock level.
SWCG levels are 3-4ppm min. depending on your CYA level within the recommended SWCG range.
The 7.4pH should be within margin of error for the recommended 7.5 acid target drop performed @ 7.8pH peak.

As for the bubbles, I'd say it's Co2 outgassing and collecting on the walls. Water contains Co2 and is controlled by your TA. Beyond that, Chem Geek will have to explain it as I have a good idea of how it works, but I'm a little rusty. I can bet though that once you take the above steps to get your water chemistry in-line for a SWCG pool, it'll go away.
It's possible it could be coming from your SWCG, but those bubbles are Oxy/Hydrogen bubbles and don't usually stick all over the walls of the pool. You'll see them come out the return jet when the SWCG is running.

 

[Deb04]

Thanks for the response.

The TA is 70.
CH is 220

The FC is so high b/c I brought it up to shock level last night and it's drifting down. The SWG is off. The above measure was as of around noon. Now it's 10.

The CYA is low b/c we had to drain and drain after all the rain we had last week. It was about 55 before that.

Note that the pH was measured last night before I put the Chlorine in.

 

[y_not]

Were you just doing an OCLT last night? Or did you pass all 3 criteria for completion of the shock process?
Ah, ok, so you measured pH with FC under 10ppm?
Above 10 on FC and pH is inaccurate. My bad, I totally missed that equation in your numbers.

I would leave your CYA until after you have shocked.
Let us know the results of your OCLT though.

 

[Deb04]

I passed OCLT last week. All was fine until I put the cover back on. Not going to shock again until the weekend is over.

Compounding factor. We just lost electricity to the pump and need to call an electrician. Probably won't have that fixed until Monday. I feel confident in the water quality today as the pump was running last night. Hoping we can still swim tomorrow. It's 95 degrees here and I have a house full of guest.

 

[y_not]

You said you had raised the CL to shock level and it was coming back down. Was this left over since your last outbreak and shock, prior to putting the cover back on then removing it to only be presented with another outbreak? I'm a little lost as to the timeline of your various outbreaks and when you shocked.

You should not be swimming in a pool that isn't clear, has an algae outbreak, even pending, or both. A. It's a safety hazard not being able to clearly see to the bottom. B. It's a health hazard to the swimmers.

Better to shock it now and get a lead on it, as the longer that algae sits, the more it multiplies and the longer it takes to clear it. Not to mention it costs more in CL too.
You can swim while shocking, once the water begins to clear. It's safe up to FC shock level for your CYA.
Be sure to lower your pH to 7.2 prior to starting the shock process. Remember, only measure pH when FC is at, or below 10ppm.

Since you can't power your pump, keep on the CL with bleach. Use pool calculator and manually brush the pool after each bleach dose. Then brush it to stir it up periodically throughout the day. Putting the cover on will just make things worse, due to no circulation. Of course the cover is fine in between brushings, just don't put it on and forget about it is all.
The UV does break down chlorine though, which is beneficial during the shock process. So ideally leave it off as much as you can, or all. If you're concerned the cover is a source of algae re-infestation, then toss it in the pool while @ shock level for an hour or 2.

However, with no filtration, It's going to get ugly fast with a bather load. Not to mention you won't be able to filter out the dead algae. It's not ideal, but It's doable if you stay on top of the brushing and CL additions.

 

[Deb04]

First of all, let me clarify that the pool is not cloudy in the sense you can't see the bottom. Im talking about the difference between a crystal clear pool where you can see the date on a penny on the bottom and just a little off, probably better than most non-TFP pools.

Timeline:
About two weeks ago the pool was covered with the solar cover for the night. Looked perfect.
CYA was 55,
FC was 5,
CC was 0
ph was 7.5.

Then it rained for a week and we didn't take the cover off. Had to pump out water during that time. Took the cover off and it looked slightly cloudy. Slightly, as in non-TFP owners would not notice.

FC was 4
CC was <0.5
CYA was 40
Ph was 7.3

I brought it up to shock levels (16) and turned the bubbles up. Passed the OCLT that night and the water was crystal clear again.

Wednesday night we put the solar cover on again. Thursday the water was slightly (again, slightly) cloudy.
Thursday's test was
FC = 4
CC< 0.5
CYA = 40
ph= 7.4
TA=70
CH=220

We had a house full of guests and it was 95 degrees Thursday - yesterday so I didn't want to do the shock process. I brought the Chlorine up to 16 Thursday night just to try to get us through the weekend. Friday, after about 6 hours of sun, tests were
FC = 12
CC< 0.5

Left the solor cover off since Thursday as I suspect that is why things got cloudy again.

We had a problem with the electricity to the pump, but have gotten that straightened out and it is working.

Today, pool is slightly cloudy, just to the tfp eye. I'm going to start shocking in a bit, now that the guests are gone. I'm planning on putting the cover on at some point when the pool is at shock levels to kill anything that might be on the cover.

Today's test
FC = 7.5
CC <.5
pH = 7.3