Struggling with Algae

[Ksbguy]

Hello,

First, I wanted to say thank you for the wealth of information!

I have read here for a while and haven't had the need to ask for help yet but stumped with a mild algae problem that keeps coming back.

I have a 14,5000 gallon plaster pool about 6 months old using liquid CL. Followed levels recommended on the pool math app. I'm in SW Florida.

Pump is run for 12 hours daily at 45GPM flow rate.

Water Temp is 80F right now and I keep the chemicals at these levels:

CYA 40.
FC 4 - 6. (Never seen CC past .5 and 0 right now)
TA 60
PH 7.6 (Have to add acid daily due to new plaster)
CH 350
Phosphates 0
Copper .2ppm

I'm using TF-Pro test kit and test daily with the DPD Powder. I never let FC drop below 4 and am adding 20-36 oz daily of Chlorine.

Pool is brushed weekly and vacuumed every 3 - 4 weeks. It's under a screened enclosure and doesn't get much debris the skimmer can't handle. I use a skimmer sock and clean the filter every 3 - 4 weeks when vacuuming.

I use RO water to add water to it now since no rain here.

A few months ago I put a solar cover on the pool that stayed on for about a month. I never removed it but opened up a corner to check chemicals daily. When I finally removed it I was surprised with patches of green algae all over the bottom of the pool.

I followed SLAM for a week, at that time my CYA was 30 and I kept FC at 12 for about 4 days at which point the water was clear. The CC was never past .5 and the FC never dropped more than .5 overnight even with the algae.

I put the cover back on and two weeks later had the same problem again. Followed SLAM again and never used the cover after that.

Ever since then I get mild green Algae that keeps coming back, it's like the gift that keeps on giving. Currently running SLAM now with FC at 16.

I know CYA/FC chart says 5-7 for my levels and I try to keep it at 5 minimum but would a day of dropping to 4 for example really cause the algae to come back so quickly?

I attached some pictures of the algae and aside from that my water is crystal clear and FC does not drop overnight. I don't like the idea of high FC levels on a new plaster pool...

Thank you!

 

[DrewLG]

Welcome to TFP! You know way more than I did when I made my first post here.

Pump is run for 12 hours daily at 45GPM flow rate.

Wow, that's a lot. Why so much?

I know CYA/FC chart says 5-7 for my levels and I try to keep it at 5 minimum but would a day of dropping to 4 for example really cause the algae to come back so quickly?

With CYA really at 40ppm? No.

As you know, the cornerstone of the TFP method is accurate testing. Are you doing your own testing? What test kit are you using?

I don't like the idea of high FC levels on a new plaster pool...

Why?

 

[Newdude]

I know CYA/FC chart says 5-7 for my levels and I try to keep it at 5 minimum but would a day of dropping to 4 for example really cause the algae to come back so quickly?

If it stayed at 4, then you'd be fine above minimum FC for 40 CYA. But FC swings and you're likely already losing closer to peak season levels in FL. Or at least more than me in NY.

So if you're at 4, and you lost 3 today, that's no good.

I don't like the idea of high FC levels on a new plaster pool...

Go as far down the rabbit hole as you need in the deep end sub forum. CYA buffers the chlorine and it's less harsh than tap water.

It's safe up to SLAM Level for all people, finishes and equipment. (40% of your CYA, or 16 FC for 40 CYA). You are saving nothing by spilling hairs between 4 and 5. Keep the FC between 6 and 9 and we'll never discuss your algae again.

the FC never dropped more than .5 overnight even with the algae.

Then I'd usually say it's pollen if the OCLT passes. How are you testing ? Phosphates and copper testing came from the pool store. They aren't open for either half of the OCLT.

 

[HermanTX]

You have stated you have read a lot on the forum but as others have said, you are living on the edge with a FC of 4ppm.
Believe in the FC/CYA Levels chart. That is golden. Also, test using your own test kit.

If you are using LC then you are dumping it and the FC will immediately rise but it will be consumed throughout the day and will drop, possibly below your 4ppm. How often do you add LC? How often do you test?

To rid yourself of algae, then you need to follow TFP with never going below the minimum, you should start testing daily for several reasons
1) your water is over 80F
2) you are using LC.
3) you are new to TFP and to pool maintenance - be excited to test every day, be excited to add LC daily to maintain the target FC levels, - once you get to know your pool and how it reacts when you add LC daily then you can back off a little but you have to learn your pool - if not, it will bite you by creating algae!!!

 

[Ksbguy]

Welcome to TFP! You know way more than I did when I made my first post here.



Wow, that's a lot. Why so much?



With CYA really at 40ppm? No.

As you know, the cornerstone of the TFP method is accurate testing. Are you doing your own testing? What test kit are you using?



Why?

I kept the water turnover the same as pool company left it and how they all do it here. But they had it running for 8 hours at 70gpm so I calculated the flow and run it for 12 at 45gpm. Instead of 8kw of energy daily I use 3.5kw.

Test daily with TF-PRO.

 

[Ksbguy]

If it stayed at 4, then you'd be fine above minimum FC for 40 CYA. But FC swings and you're likely already losing closer to peak season levels in FL. Or at least more than me in NY.

So if you're at 4, and you lost 3 today, that's no good.

Go as far down the rabbit hole as you need in the deep end sub forum. CYA buffers the chlorine and it's less harsh than tap water.

It's safe up to SLAM Level for all people, finishes and equipment. (40% of your CYA, or 16 FC for 40 CYA). You are saving nothing by spilling hairs between 4 and 5. Keep the FC between 6 and 9 and we'll never discuss your algae again.

Then I'd usually say it's pollen if the OCLT passes. How are you testing ? Phosphates and copper testing came from the pool store. They aren't open for either half of the OCLT.

Hello,

I never let it drop below 4. I test daily and I'm adding 20-36oz daily.

The CYA\Chlorine chart says 5 - 7 for 40 CYA. I was striving for that but did see 4 at times - didn't think a day at 4 would be enough to cause algae but I will keep it higher.

Pool store tested copper and phosphates but I have the taylor kit for testing phosphates and it's zero.

OCLT passes and passed today again. Was 16ppm last night, is 16ppm this morning and my water is crystal clear now. As far as SLAM I'm finished but I'm afraid I'll be doing this again in two weeks even keeping FC between 5 - 7. I'm afraid something else is going on, either the Chlorine I'm buying from pool store has lost it's potency or my test kit is inaccurate.

 

[Ksbguy]

You have stated you have read a lot on the forum but as others have said, you are living on the edge with a FC of 4ppm.
Believe in the FC/CYA Levels chart. That is golden. Also, test using your own test kit.

If you are using LC then you are dumping it and the FC will immediately rise but it will be consumed throughout the day and will drop, possibly below your 4ppm. How often do you add LC? How often do you test?

To rid yourself of algae, then you need to follow TFP with never going below the minimum, you should start testing daily for several reasons
1) your water is over 80F
2) you are using LC.
3) you are new to TFP and to pool maintenance - be excited to test every day, be excited to add LC daily to maintain the target FC levels, - once you get to know your pool and how it reacts when you add LC daily then you can back off a little but you have to learn your pool - if not, it will bite you by creating algae!!!

I updated my post to reflect more information. Using TF-pro testing daily with DPD powder for the Chlorine - I don't even bother with the comparator test since I can't differentiate between the levels there. MY FC is never below 4, it's normally 5 - 7 but I have tested and seen it at 4. What's interesting is a week ago it was clear, FC has not dropped below 5 for a week and yesterday I had algae in my pool I showed in the pictures.

I'm adding 20-36oz of LC daily.

 

[Ksbguy]

This morning I have zero algae, water is crystal clear, it was 16ppm last night and is 16ppm this morning and CC is zero. According to SLAM this tells me I'm done but I think it'll be back again, been through this three times now. Will not let FC drop below 5 going forward.

Is SLAM always required every time you see even a little algae on the bottom?

 

[Newdude]

I'm afraid something else is going on, either the Chlorine I'm buying from pool store has lost it's potency or my test kit is inaccurate

With reasonable suspicion, test 15 mins after adding for the foreseeable future, until you're confident you're consistently hitting your target.

Test daily with TF-PRO

AWESOME. We're just looking out, and phosphate results from lesser known members are usually suspect.

As far as SLAM I'm finished but I'm afraid I'll be doing this again in two weeks even keeping FC between 5 - 7.

I'd run hot for a while until you're confident the FC will hold. I target a 10, but be mindful that the PH test is invalid at 10+ FC so you'll have to test when it's 9.5 -.

Usually when we see repeat blooms when SLAM is followed to the letter , algae is hiding in plain sight and is reintroduced as soon as you stop SLAM. Your mission is a full blown algae treasure hunt. Every inch is suspect until proven otherwise. Ladder rails for example hold a couple gallons of old water, each. Light niches, autofills, all up in the guts of the skimmer....... etc etc etc. Every. Inch.

 

[SecoSteve]

You mentioned using a solar cover, and also having it on for a month. Is anyone actually swimming in the pool? If the water stays covered and unused, I can see how algae can get a hold on your water. Especially, if your FC is on the low end. The solar cover can be a great place for algae to hide as well.

 

[Ksbguy]

With reasonable suspicion, test 15 mins after adding for the foreseeable future, until you're confident you're consistently hitting your target.

AWESOME. We're just looking out, and phosphate results from lesser known members are usually suspect.

I'd run hot for a while until you're confident the FC will hold. I target a 10, but be mindful that the PH test is invalid at 10+ FC so you'll have to test when it's 9.5 -.

Usually when we see repeat blooms when SLAM is followed to the letter , algae is hiding in plain sight and is reintroduced as soon as you stop SLAM. Your mission is a full blown algae treasure hunt. Every inch is suspect until proven otherwise. Ladder rails for example hold a couple gallons of old water, each. Light niches, autofills, all up in the guts of the skimmer....... etc etc etc. Every. Inch.

If the FC levels go up and match what pool math said it should have been then my LC should be good right? I've done this test before but waited a couple of hours.

FC drops 1 - 1.5 during the day depending on amount of sunlight which is normally high here. Overnight I haven't seen it drop when I've tested.

I add my LC in the morning first thing and the pump runs 7am - 7pm.

 

[Ksbguy]

You mentioned using a solar cover, and also having it on for a month. Is anyone actually swimming in the pool? If the water stays covered and unused, I can see how algae can get a hold on your water. Especially, if your FC is on the low end. The solar cover can be a great place for algae to hide as well.

No, we weren't using it when it was covered. That was months ago and I haven't used that cover since. I had zero problems until I used that cover and once the algae showed up it's been tough to make it not come back. I've been told the covers will do exactly that if left on too long.

 

[Newdude]

If the FC levels go up and match what pool math said it should have been then my LC should be good right? I've done this test before but waited a couple of hours

Yeah. You'd also notice tomorrow being lower than you expected. But for now confirm the first couple tests 15 mins later.

Overnight I haven't seen it drop when I've tested.

A good omen for sure. The SLAM could be clearing the water but leaving a fouled light niche (for example). You pass SLAM and OCLT and it takes a while to reintroduce enough to overcome the regular daily doses. It's a 50/50 shot, with multiple SLAMs one is either letting it fall below min again for new algae, or it was hiding in wait from the first time. From all you've detailed, I believe you are maintaining your levels post SLAM, which points to old algae.

 

[Rancho Cost-a-Lotta]

The only time I've had algae in the last few years is when I've left my solar cover on too long. I didn't notice it until I pulled the cover off.

Try following the protocol for mustard algae for better results.

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.troublefreepool.com

 

[Ksbguy]

The only time I've had algae in the last few years is when I've left my solar cover on too long. I didn't notice it until I pulled the cover off.

Try following the protocol for mustard algae for better results.

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.troublefreepool.com

Sounds like I have mustard algae if it's a yellow color. From the link and 40CYA looks like I need FC of 24ppm now - this sounds very high and will probably remain above 10 for weeks given at most I see a drop of FC of 1ppm/day.

I've had a large boat for decades and I never thought I'd say this given the maintenance on a boat but the pool appears to be worse.

 

[mknauss]

Read the article. The MA FC level is only for 24 hours. You do a normal
SLAM Process first.

 

[Ksbguy]

Read the article. The MA FC level is only for 24 hours. You do a normal
SLAM Process first.

Thank you, I did and saw that. As far as I'm concerned my SLAM is done overnight. MY FC has been at 16ppm since 7pm last night and I've added none. My water is also clear as can be. Any risk with new plaster and 24FC levels. I read the CYA buffers it but it's just concerning. What I meant was it'll remain at very high levels for easily 2 weeks given I only see a drop of 1ppm per day from sunlight.

 

[mknauss]

I would not do it with very new plaster. How are you confirming you have mustard algae?

 

[Ksbguy]

I would not do it with very new plaster. How are you confirming you have mustard algae?

I don't know that I do, just going by the fact that I've done SLAM on pool several times and it keeps coming back. My FC has not dropped below 4 but it hasn't been 5 - 7 constantly either but the minimum on the chart does say 3... The other concern too is the PH while these FC levels stay high that I can't measure due to shock levels. I have to add 8-12oz of acid daily to keep PH down. The plaster is 6 months old.

How do I confirm the mustard Algae? I can't tell from looking what it is...

 

[mknauss]

Mustard algae tends to grow on the walls and floor of the pool on the shaded side.

Is that what you see?