maybe algae sediment?

[bobandmeg]

Firstly... We've long been BBB believers and have used this forum and "pool school" extensively and successfully. We're in year two of loving pool ownership, and our own water tests, and the tests at the local pool store, always show good levels across the board due to your great information. So, THANKS!

Secondly... We never felt the need to post all this time because so much great info is readily available. But, today is the day.

We're unsure if we have the beginnings of an algae concern. After a period (say, overnight) of non-use, we find sediment on the floor of our pool. It is almost like "ash" from a fireplace in that it is extremely fine and disappears when touched. No grit like sand or dirt would have.

Here are our pool specs:
- 15 x 30 above ground
- 10,000 gallons
- sand filter runs 5 hours per day on a timer
- solar cover at night
- the pool receives full sun 100% of every day
- some blow in from trees at the edge of the property but not a major source of litter
- no nearby activity (e.g. construction or similar) that would cause a lot of dust

Here's our regimen:
- We check all levels daily
- We never see wide swings in the numbers
- Most of the time we only need to add some liquid chlorine, sometimes some muriatic acid
- We vacuum about twice a week
- Rigorous swimming for multiple hours per day (we're "that house" where all the kids come to play and hang out)

Here's our levels today (which are very similar to what they are every day):
- PH = 7.6
- CYA = 40
- FC = 5
- CC = 0
Water is crystal clear, the walls are clean too.

Steps taken so far.
- We backwashed last week.
- We cleaned the solar cover to ensure we're not dropping in sediment of any type every night.
- We bought a brush and scrubbed all the walls and seams (despite no visible evidence of any issue)
- We pulled the ladder out and found a bunch of hidden grime on the back side. We cleaned aggressively with bleach and a brush. Rinsed, replaced.
- We carefully vacuumed, flushing to waste rather than filter.
- Rechecked all levels after topping the pool off with hose water. Needed a little chlorine to get back to the numbers shown above.

Two hours later, with the filter still running, we had sediment at the bottom again. Same type of ashy stuff that disappears when you try to touch it.

What do you think we have settling on the bottom of our pool?

What steps can we take to eliminate? Shall we just increase our filter time and continue with the new addition of manually brushing?

Should we "shock"?

Is it really nothing to worry about since our numbers are continually good?

Thanks in advance!

Bob and Meg

 

[kimkats]

I think you have a need to do a mini SLAM due to finding the stuff on the ladder. Head it off before it gets ahead of you.

What you are seeing is the work of your bleach trying to keep your pool clean BUT that stuff on the ladder is trying to beat it.

Here is a link to doing a SLAM. Pool School - SLAM - Shock Level And Maintain

Good luck!

Kim

 

[bobandmeg]

Hi Kim,
Thanks for the reply. We just read the tutorial that you linked and are capable of following those instructions.

Our questions are:
- You say "mini-SLAM"... what we just read seems very aggressive for clear water and good water test results on a very consistent basis. Is "mini-SLAM" a thing, or must we go full-bore?

- Is it possible that the steps we took today (increasing the filter duration, scrubbing and vacuuming to waste, pulling the ladder out for a thorough cleaning with bleach) will get us there without having to pull everyone out of the pool for the next bunch of days? That is, is it possible to "wait and see" and trigger the more aggressive SLAM approach when we see some sign or another in a couple days?

Thanks again!

Bob and Meg

 

[kimkats]

When I say mini SLAM in your case it is because I do not think it will take long at all. You are not in a full blown algae bloom.

What I would do is-

-As soon as everyone is out of the pool for the day raise you FC to SLAM level.

-Right before you go to bed test again to see where you are at. Write down your results.

-Test as soon as you get up (after coffee is started of course!). Compare to your last test at night.

What are the results? If you lost any FC you should know that you need to have your FC at SLAM level as much as possible for the next two or so days.

This is called OCLT. Here is a link to it.

Pool School - Perform the Overnight FC Loss Test (OCLT)

To me this test is the one that will tell you if there is anything "brewing" in your pool. I do this test about every other week just to make sure. I am very much a better safe than sorry person.

Now saying that, if you have kids that are wanting to swim during the day but you do need to do a SLAM you can do a slow one in that you let the FC sit just under SLAM level and let them play. As soon as they are out add more bleach to get it back to SLAM level.

I hope this helps.

Kim

 

[bobandmeg]

Very much, thank you!!

 

[Richard320]

"Mini-SLAM" is sort of a misnomer. It's a full SLAM, with all the same rules and the same three criteria to pass at the same time before it ends. It's just that this will probably be just one of the faster ones.

 

[bobandmeg]

Well, you were right (no surprise!). We ran the overnight test, and found the FC drop that indicates that we're fighting something.

We were never aware somehow that this type of overnight test should be part of our usual routine to avoid surprises... We will incorporate this into our processes going forward.

More updates soon when we get everything back to normal. Hopefully before Thursday when a bunch of kids will be wanting to jump in to cool off after our weekly basketball session.

 

[kimkats]

For Thurs. you can let the FC drop just under the SLAM level while the kids are there and push it back up when they leave.

It is a joy to help you! You listen and learn!

Kim

 

[bobandmeg]

Thanks guys! I think we are on our way to success and will report again tomorrow.

One question though... We thought that great water levels and a good manual cleaning routine were the way to ensure that these problems don't occur. Obviously we were wrong. What additional steps can we take to avoid a repeat of this issue going forward?

 

[Swampwoman]

In my own pool, I ride the min. fC for my cya level a point higher, and generally dose for a possible 50% FC reduction...not that its usually that much. However, with your level at 5, it sounds like you're doing roughly the same.

I'm not familiar with above ground pools, but suspect sometimes in some models the circulation and filtration may not be as strong as in some in-grounds, just based on hearing reports like yours.

If the algae is appearing in areas of low circulation despite above-min FC, I might
a) increase my filter run time to improve circulation
b) perhaps add a bit of my chlorine to the suspect area and mix it with a brush and
C) periodically brush areas with lower circulation

 

[kimkats]

The only thing I will add to the above is a all over pool brushing of the walls at least every other day. Make a habit of jumping in and running around the pool in such a way that every bit of the wall gets brushed.

My husband's only job with the pool is to brush the walls. I had noticed that my tests were off a little and asked when he had last brushed them. "They look good to me." Really? I had him come out to the pool with me and did one little swipe with the brush which caused a cloud of yellow to come off the wall! He jumped in right then (clothed I might add LOL) and brushed the walls!

Can you please do this for me? Post your pool details in your siggy. Here is the link on how to do it.

Pool School - Read This BEFORE You Post

Here is another link to show you where your stuff should be.

Pool School - Recommended Levels

I tend to have my FC just over the max because I know my sun is hot and all day. That way there is still FC at the end of the day.

Kim

 

[bobandmeg]

Thanks again! Signature updated.

Here's our progress update: Yesterday, maintained SLAM levels about every hour all day long, adding liquid chlorine as needed to bring FC to 12+. Over night, FC went from 12 at bed time, to 10.6 after brewing morning coffee. Lots of sediment on the bottom of the pool. We'll raise FC this morning again and then we plan to let FC drop low enough to get in for a good mid-day brushing and vacuuming, followed by raising FC again. And here's what we look like as of this morning:



According to the link you provided, the appropriate levels, with bleach, are:
FC 3-7 (See chart)
pH 7.5-7.8
TA 70-90+
CH 0-350 (Don't add)
CYA 30-50


Our usual numbers, checked daily, have been:
FC = 4 (the mid point value for CYA in the 30-40 range per the linked chart)
pH = 7.6
TA = 140
CH = We don't test for this because we're in an AG pool (should we?)
CYA = between 30-40 depending on the day


Edit: In the pool calculator explanations of each of the items being measured, I read "If you have a SWG or very high levels of direct sunlight, CYA is typically kept between 60 and 80." Our pool is 100% sunlight all day every day. So perhaps we should be aiming for higher CYA, and therefore targeting FC at closer to 7 than the current 4. Your thoughts?


Our routine:
- Lots of swimming splashing on a daily basis
- Vacuum once per week on average, two times lately due to issues
- Due to issues, we have begun brushing walls frequently (and will continue to do so from now on)
- I'll also pull the stairs out once a month for a thorough cleaning
- Do we need to pull the light kit and clean it?
- We're looking into adding DE to our sand filter per suggestions on this site

How does that all sound?

 

[kimkats]

WOW! That is a clear pool! How do you keep it so clear? LOL

Your plans all sound spot on!

-CYA-You can bump it up a little at a time. See if the increase in CYA is helping you hold you FC during the day. It is easier to add than take out so go slow.

-light-I would take it out and scrub when you take the ladder out. Make sure to look in and all around your skimmer basket including the door as some have found algae hiding there.

-TA-Here is a link on how to lower it. This is the last thing you do when you are clearing your pool. I think you are there!

How to lower TA

-CH-nope do not bother with it. I have never even tested mine.

-DE-I add it to add a sparkle to the water. Look at your water at night with the light on. Add DE and let it filter during the day and look again that night. You very well may see a difference that fast.

Thanks for adding your pool info. in your siggy!

Now go jump in your wonderful pool! CANNON BALL!

Kim

 

[bobandmeg]

Thanks again Kim! We were going through withdrawal while the site was down, but luckily had learned enough to keep our SLAM going.

One update, also reflected in our updated signature, is that I began wondering if our pool was truly 10,000 gallons as the pool store had told us and was printed on our paperwork. After several online calculators showed that we're really closer to 14,500 gallons, we knew some slight adjustments to our calculations for the SLAM were needed. We were aiming for FC = 12 at the time (due to CYA in the 30-40 range) but were adding too little liquid chlorine to actually reach that, thus slowing our SLAM. Once we updated the pool calculator with our proper number of gallons, we were more easily reaching 12. At the same time, we began slowly raising our CYA, and aiming for a FC = 14 instead. Due to our full sun location, we're going to keep CYA in the 50-60 range going forward, and all other related levels adjustments.

All that to say this: We are indeed "there" as of this morning. We had about 10 tests and adjustments yesterday at the new higher FC = 14 level, and our final reading at bed time was FC = 14.8. This morning (after coffee was brewing) FC = 14.8. No loss at all. CC measured at .2. Water is absolutely crystal clear. That's the trifecta for passing the SLAM I do believe. YAY!

With CYA adjustment in progress (again, aiming for 50-60 rather than 30-40 due to 100% full sun conditions... we're up to 40 so far), and our new correct gallons in the calculator, our maintenance goal level for FC will be 6, with all our other levels matching the targets we always achieved already as noted above. We'll work on TA little by little, but it seems it's not as urgent as other measures. We've adjusted our filter pump timer to run for 6 hours per day (up from about 4 hours per day previously).

And, we have set recurring reminders for Fridays to do the overnight test, and for a month from now to proactively pull the pool ladder and light kit for a scrub. We'll plan to do that at the start of each swim month each year just to be safe - it takes less than an hour to do the work, so it's worth it to avoid a week of SLAM.

LAST QUESTION (ha ha ha... for now... I'm sure we'll have a bunch more over time): On Friday, we're heading out for vacation for the weekend. Should we leave the solar cover on the whole time? And, what's the best bet for maintaining FC while we're not here to add it in ourselves?

 

[kimkats]

You did it! You really did it!

Good catch on the water volume! The pool store can't even get that right!

Pull your CYA sock out for now. Do this so you can use pucks in a floater while you are gone. You know what a puck adds (CYA) and can adjust your water go with it.

Have fun!

Kim

 

[bobandmeg]

Shoot, we already added CYA powder via the skimmer basket yesterday. Should we backwash to try to clear it out of the filter? Or is there another "puck like" solution that doesn't also add CYA while it's chlorinating?

Also, here's some pics of our setup just for fun. I built the Trex-topped deck myself earlier this summer, and also designed/built the lifeguard chairs and matching Adirondacks. Fun place to hang out!

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fixed pics

 

[kimkats]

You are good. Just know that your CYA will be a little higher so you FC will need to be a little higher. It will really only matter if you had to SLAM again (which we both know will not need to be done again since you found TFP!)

Love the set up! NICE!

I love the dolphin cut out on the gate. Those life saver chairs! NICE!

That screened in porch-I bet there have been some fun time on that!

Can I come play at your house? LOL

Kim

 

[bobandmeg]

Thanks Kim. You're so nice to give all this patient and wonderful advice (along with all the other experience members on this forum). BBQ at my place anytime you're up in PA.

 

[bobandmeg]

UGH! Panic attack begins here.....

I think we're still fighting something!!!!!!!!!!!

Since our successful SLAM, and being absolutely positive (like 3 full water tests per day) to ensure that all of our levels are perfectly spot on at all times, and scrubbing walls and vacuuming daily.... we're still getting sediment on the bottom of the pool just like we did at the start of this process.

We ran an overnight loss test last night and dropped 1.4 FC. This seems to indicate to me that we're still fighting something. What the heck?

Today, we're scrubbing all pool toys and floats (first time), pulling the light kit (first time), pulling the ladder (again!), scrubbing inside the skimmer (first time), backwashing (again!!), wall scrubbing (again!!), vacuuming (again!!!!), cleaning the pool solar cover (again!!!)....

We thought that crystal clear water and perfect levels were the goal - we're achieving that. Are we being too worried? Do you agree that our problems aren't over? Do we have to lose yet another week of our already-too-short summer? How can we avoid problems if perfect levels and constant cleaning don't help?

We have a weekend (and hopefully summer) of pool parties planned, and are so beyond frustrated that it's ruining our enjoyment of even owning a pool.

Please talk us off the ledge.

 

[Defgufman]

I keep my cya between 60 and 70 because of the full south eastern sun. When I was lower, my FC would drop to quickly in the day.