Dead algae not filtering out through sand filter

Gabrielle

Member
Aug 10, 2018
6
Bordeaux France
I had a super green pool as polaris pump failed this included small beetles and animals that look like crickets but live in water and water boatman. My pool guy shocked and added 4x green to blue. Ph is 7 I have since shocked twice and added flocullant. The algae is dead white/pink and lying on bottom. I do not have enough pressure to use a vacuum so am dependent on the sand filter. It is clearing the pool every time I backwash I can see the dead algae however it is taking ages and ages. Any ideas? it is a salt water pool I am in Bordeaux France :D
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Hello and welcome to the TFP forum! :wave: To help sand filter better, sometimes we add some DE as noted on the https://www.troublefreepool.com/content/133-add-de-to-a-sand-filter page. Having said that, I'll give you some other things to consider:
- Please visit our ABCs of Pool Water Chemistry and save/use those Vital Links below in my signature. Don't forget to update your sig too.
- Floc is horrible for a filter, especially sand as it clogs it up. If you are not able to vacuum to waste, the floc may have already compromised your sand. We rarely recommend floc.
- We kill/remove algae following a process called SLAM. You might want to review that page as well.

We understand the resources you have available in Bordeaux may be different from the states, but chlorine (regular bleach) is the best sanitizer in cases like this to kill algae. Salt water generators generally can't keep up. Let us know if you have any questions.
 

Gabrielle

Member
Aug 10, 2018
6
Bordeaux France
Hello and welcome to the TFP forum! :wave: To help sand filter better, sometimes we add some DE as noted on the https://www.troublefreepool.com/content/133-add-de-to-a-sand-filter page. Having said that, I'll give you some other things to consider:
- Please visit our ABCs of Pool Water Chemistry and save/use those Vital Links below in my signature. Don't forget to update your sig too.
- Floc is horrible for a filter, especially sand as it clogs it up. If you are not able to vacuum to waste, the floc may have already compromised your sand. We rarely recommend floc.
- We kill/remove algae following a process called SLAM. You might want to review that page as well.

We understand the resources you have available in Bordeaux may be different from the states, but chlorine (regular bleach) is the best sanitizer in cases like this to kill algae. Salt water generators generally can't keep up. Let us know if you have any questions.

I have S:LAM 3x we call it shock chlorine level now v high and I have temporaily turned off the salt. It is improving and I have not seen any animals for 3 days or so. These two pics are a week ago not before we shocked the first time and today. It is just cloudy now
 

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tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,122
Franklin, NC
Shocking and a SLAM are different. You need to read and follow the SLAM directions. It’s a process, not a single addition of chlorine.
 

Gabrielle

Member
Aug 10, 2018
6
Bordeaux France
My ph is good 7.2 the chlorine was v low so added some more free chlorine and now is 5.0ppm too high and the pool has rapidly gone more cloudy. I have been trying to sort now for 2 weeks am beside myself so should I SLAM again?
 

Flying Tivo

Well-known member
Jan 24, 2017
602
Monterrey, NL, Mexico
Cloudy water usually means Algae. Yes you need to SLAM. You need to follow the SLAM directions, what you been doing is not SLAM, its just adding shock which is totally different.

Felipe
 

AimeeH

LifeTime Supporter
TFP Guide
Apr 2, 2012
2,002
Columbia SC
My ph is good 7.2 the chlorine was v low so added some more free chlorine and now is 5.0ppm too high and the pool has rapidly gone more cloudy. I have been trying to sort now for 2 weeks am beside myself so should I SLAM again?
Hi Gabrielle

SLAM is a process.

Shock
Level
And
Maintain

To clear the pool, you need to follow that process which is to bring your free chlorine up to shock level for your CYA level----see this chart for that target. https://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

Then you need to maintain your FC at that level until the water is clear, CC measures .5 or less and overnight free chlorine loss (OCLT) test is less than 1

You can't have followed this process if you water is not clear.

Once clear, you need to maintain you FC at the proper level for your CYA and algae can't come back.

Take a look in pool school and ask questions as you go. https://www.troublefreepool.com/content/
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
I had a super green pool as polaris pump failed this included small beetles and animals that look like crickets but live in water and water boatman. My pool guy shocked and added 4x green to blue. Ph is 7 I have since shocked twice and added flocullant. The algae is dead white/pink and lying on bottom. I do not have enough pressure to use a vacuum so am dependent on the sand filter. It is clearing the pool every time I backwash I can see the dead algae however it is taking ages and ages. Any ideas? it is a salt water pool I am in Bordeaux France :D
Hello Gabrielle.

Does your filter have the ability to pump to waste? If so you could manually vacuum to waste to remove the algae (and some water) from the pool. Watch your water level doesn't go below the skimmer.

If you have been continuously vacuuming dead algae it is very possible that there is still live algae in the pool, that dies every time you shock, giving the impression that you are not removing the dead algae. Truth may be that the algae continues to die as fast as you can remove it.

Our SLAM procedure is a scientifically, as well as practically proven method to completely eliminate algae and bacteria from your pool.

I hope you will take the time to read our SLAM process, as well as the ABCs of Pool Water Chemistry in our Pool School. Maintaining the proper FC to CYA ratio and understanding exactly what the pool needs (and does not need) is key to our pool care, and you will need reliable and repeatable test results to be successful.

Thanks for posting.
 

Gabrielle

Member
Aug 10, 2018
6
Bordeaux France
Hi guys
I tried to buy DE is banned in Europe ? carcinogenic. I think it sounded a great idea. The pool guys here were horrified
I have high free chlorine the problem is I cant vacuum as pool pressure too low. I do not have algae just dead algae which site on bottom and the sand is not clearing very fast,
I have added a bit more floc and next time I backwash I will do for 5 mins or until runs clear I should have done for longer in the beginning. .
The pool is starting to clear now just skimmer end is cloudy is just uber slow. 60% only now all animals and debris gone.


My husband said just drain the pool sweep and refill. Is 75msq and then water is cold rather sort it.
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
We do not normally recommend using floc, it usually creates more issues than it corrects.

Floc will need to be vacuumed to waste, does your filter have that option?

Vacuuming floc into your sandfilter will eventually gum up the sand requiring you to change it.

A sand filter is more than capable of filtering dead algae, yours should be no different.

You insist that you do not have live algae, yet where is all this dead algae coming from?

What are your FC, CC, and CYA (stabilizer) levels?
 

Gabrielle

Member
Aug 10, 2018
6
Bordeaux France
ph 7.4 salt 4000 fc v high > 5ppm I dont have a kit for the rest.
The dead algae is because my husband opened pool left the bungs in the skimmer and it uncovered for a month.
It is clearing. SLOWLY>>>>>>>>>>>>>>>

I cant vacuum have waste but pool pressure too low. Pool is big c 12x 6 m 75msq

should I drain ? start again debris free and animal free now was totally disgusting

- - - Updated - - -

If I have algae surely be green No?? Is bright blue.
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
ph 7.4 salt 4000 fc v high > 5ppm I dont have a kit for the rest.
The dead algae is because my husband opened pool left the bungs in the skimmer and it uncovered for a month.
It is clearing. SLOWLY>>>>>>>>>>>>>>>

I cant vacuum have waste but pool pressure too low. Pool is big c 12x 6 m 75msq

should I drain ? start again debris free and animal free now was totally disgusting

- - - Updated - - -

If I have algae surely be green No?? Is bright blue.
Algae spores are microscopic. By the time you see green, there are millions of them.

The floc you added should be vacuumed to waste, your ‘pool guy’ should have told you this. It is not good to put the floc into your filter. It will make a mess of the sand.

Have you looked at any of the info we have suggested? It does not seem so.

You are correct that your chlorine test kit does not measure high enough. It also measures TC (total chlorine) not FC (free chlorine available to sanitize). TC is the sum of FC and CC (combined chlorine, or chlorine combined with something else, in this case most likely oxidizing algae & bacteria).

You mentioned that you are in Europe. Can you get a FAS/DPD Chlorine test kit in your area? This will read FC and CC separately, all the way up to 50ppm.

We also need a CYA (stabilizer) level.

If the pool was full of debris and dead animals, you may be dealing with algae, bacteria, and ammonia in the water.

Can you post a picture of the pool water? Put the stairs or ladder in the picture so we can judge water clarity.
 

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