Dead Algae that won't go away!

[amboyle7]

We are at our wits end with this one.

We have a 24 round AG, approx. 15,000 gal. Sand filter (don't know details).

Water got a green tinge, so we shocked, flocked and got a mess of dead algae (brown) on the bottom.

Water was clear, chlorine and pH balanced. We vacuumed on waste setting, backwashed and rinsed the filter.

Beautiful. Crystal clear, all dead algae gone. Next day, though, the brown algae dust was back. We repeated this procedure at least FOUR TIMES, and each time, the brown dust of algae returns. My water bill is through the roof for the refilling every time we vacuum on waste, and I don't know how to get rid of the stuff!

We've had this pool for 5 years, and never had this kind of problem before.

Can anybody help???

 

[Butterfly]

Welcome to TFP

Post a full set of test results for us.

Have you tried skimmer socks?

Have you checked to see if it is blowing back from the filter to the pool?

 

[amboyle7]

We're getting the water tested again tomorrow and will post results.

Actually, I've never heard of "skimmer socks"--what are they?

Yes, we checked the filter outflow, and it seems clear. We backwashed and rinsed so many times, I think the sand is clear. It's just so crazy; we've had algae build-up in the past, but never had dead algae keep returning.

Thanks!

 

[duraleigh]

Just guessing, but if brown, dead algae appears each day on the pool floor you are almost surely killing more algae. That means you didn't finish shocking the pool correctly or have allowed your FC levels to slip too low and letting the algae regain a foot hold.

I would not vacuum to waste but rather to filter and simply resign myself to cleaning the filter. I think once you meet the specs in this list, the brown will stop appearing...
1. Your water is crystal clear.
2. You lose less than 1.0 FC during the FC overnight loss test
3. Your CC's test is .5 or less

 

[supertune]

Hi amboyle7 and welcome to TFP.
How are you shocking? Powdered or bleach/liquid chlorine?
Are you following the directions here in Pool School link at the top of the page?

Chuck

 

[RobbieH]

A skimmer sock is just that, a sock that goes on the skimmer basket to assist in filtration. You can find it in here:
pool-school/visual_encyclopedia

 

[amboyle7]

Oh, cool. Never saw one of those before.

Yes, Chuck, we did follow the directions, and we thought we had it under control, with the chlorine levels staying pretty steady where they should be. We opened it using liquid shock.

The pool store ran our water sample and here's our test results:

Saturation Index:-0.7
CYA: 69
TC: 1.3
FC: 1.3
pH 7.6
Totl Alkalinity: 88
Adj. Total Alk.: 67
Tot. Hardness: 61
Manganese: No
Cloudy: None
Staining: None
Copper Stain: None
Iron Stain: No
Green Algae: None
Black Algae: None
Mustard Algae: No
Slime/Mold: No


After testing, the pool store told us that, in all probability there is new algae forming and dying. We were told to use two bags of Burn Out Extreme, pour in some algaecide and then pour this stuff (very expensive stuff) called "Sparkle-Up" by Bioguard into the skimmer. They say it will improve the efficiency of the filter once we vacuum up all the dead goop.

They claim if we follow this protocol the pool will be crystal clear in a few days.

Which is good because we are in the middle of a heat wave and it would be nice to get a swim in sometime this summer!

But, as I speak, the water is whitish-cloudy (I presume from the shock) and layered with brown flock, so we shall see.

 

[duraleigh]

Your pool needs shock levels of chlorine...nothing else. Although it seems you have chosen to go another route.

If the pool store advice doesn't work, the very simple answer is to shock the pool correctly. Read how up in Pool School.

 

[Txmat]

If you continue to follow your pool store's advice and rely on their testing, I can almost guarantee you will be fighting this regularly and expending lots of money at the pool store. On the other hand you can study the pool school ( use the button in the upper right of your screen) and follow the advice given, ask questions here and with mostly common household bleach and muratic acid from the big box stores you will have a sparkly clean pool that you can enjoy in this heat.

 

[amboyle7]

Well, it's not really me who is turning to the pool store for advice--it's my dear husband, who doesn't seem to understand that pool stores are in the business of selling useless chemicals.

I will try to follow the pool school advice as best I can and convince my husband to do so also. Truthfully, I only just joined this site on the advice of a friend, and wish I had found it sooner.

Thanks for all your advice and help.

 

[duraleigh]

Pool management by committee is very, very difficult.

We have a mind control team that can telepathically send him subliminal messages to get his act together if you like.

We would need an article of clothing and the address of the pool store he frequents. This BBB stuff can be pretty powerful if we gang up on him as a team.

 

[amboyle7]

LOL, actually, that might work. Otherwise, I have a very handsome neighbor who's pool looks much better than ours--I might just have to invite myself over for a swim...(jk, dear husband )

 

[amboyle7]

AHA!!!

Yes, I can read after all, and I finally noticed this little tidbit under the "Pool School" tab:

Trichlor - Commonly sold as tablets or pucks that you simply put into an automatic container that passes pool water over them and they slowly dissolve - putting chlorine and CYA into your water and lowers the pH. They are incredibly convenient and incredibly insidious. The CYA that they put into your pool water doesn't get used up, and instead accumulates. Eventually the CYA level will build up to a point that renders your chlorine ineffective. Typically, everything is fine, until one day you start to develop algae and don't understand why.

ALL our problems started when we began using those nasty little tabs. My husband thought the liquid chlorine was just to inconvenient to lug around. Our CYA level is 69. I suspect this is why the algae keeps returning, despite our high chlorine levels.

We will try a little experiment. Ditch the tabs, switch back to liquid chlorine. Could the answer really be that simple?

 

[Txmat]

AHA!!!

We will try a little experiment. Ditch the tabs, switch back to liquid chlorine. Could the answer really be that simple?

Pretty much! You might want to learn how to use the Pool Calculator. If you want to lower your CYA you will have to drain a portion of your water and replace. The Calculator will tell you how much.

 

[supertune]

Bingo!

Chuck

 

[amboyle7]

Hubby looked at me like I was nuts. "Bleach?" He exclaimed. "Borax???" He cried. "Baking Soda????" He scoffed. But when he saw the chemical content and price difference, he followed my directions went to the grocery store and now I'm looking forward to a lovely pool. I believe I now have a BBB convert on my hands.

And my filter took care of clearing a portion of my water to replace because of the CYA levels--the hose broke sometime during the day and lo and behold, the water level went down pretty far. Oh well, with this heat wave, it was getting too warm anyway...

 

[Sportsman]

AHA!!!


We will try a little experiment. Ditch the tabs, switch back to liquid chlorine. Could the answer really be that simple?

Yes and no. You have to shock. You said your "high chlorine" levels. Your levels are low even for a pool with acceptable CYA> If you are really 70, that's not atrocious depending on how much sun you get, you just have to adjust your chlorine level accordingly. All the vacuuming to waste has brought it down some.

1. Get your own test kit. TF100 is best value. Test Kits Compared - Trouble Free Pool

2. Shock according to Pool School

3. After your done, know your appropriate FC range per pool calc and test/add liquid chlorine daily to maintain it. It's not as hard as you think, 5 minutes a day.

On your husband saying he hated lugging jugs, I do buy liquid chlorine instead of bleach to cut down on jugs. My cost is still less than $25/month so I don't even bother with the math on if bleach is cheaper.

Good Luck!

 

[amboyle7]

My TF100 testkit is on order. We've shocked as suggested in accordance with the handy-dandy pool calculator (pure genius, that device is!).

A couple of questions:

Can the pool be used while being shocked?

How long does it generally take for the cloudiness to go away. Its not the dreaded "can"t see your feet" cloudy but it has a whitish hue to it (I imagine from the shock dose of chlorine)?

Thanks for all your help!

 

[aa62579]

Are you continuing to keep your pool at shock level? Shocking is not a one time thing. It can take days or weeks.

 

[Txmat]

You can swim whenever the chlorine level is below shock level and the PH is between 7.2 and 7.8. You should note that at chlorine levels higher than 10 the PH test is not accurate.

How long it takes to clear is usually determined by how diligent you are at maintaining the chlorine level at shock, frequent brushing, running the filter 24 hours a day, cleaning the filter when needed. Shocking is a process not an event and works the best when you closely follow the instructions in pool school.