How to Clear Up a Green Pool
By If your above ground or in-ground swimming pool has turned green you will need to learn how to clear up a green pool. You will need some liquid or powered pool shock. You will also need some sort of pool vacuum equipment so you can vacuum the pool after it clears. The following pointers should help you clear your green swimming pool. 
Most totally green swimming pools will take anywhere from 3 – 10 ten days to clear depending on how much shock and how often you vacuum the pool while its clearing. You will want to run your filter 24 hours a day while you are clearing your green swimming pool.
You Need To Make Sure Your Filter Is Ready
The first thing you will need to do is to make sure that you filter is working at 100%. If you have a sand filter you will want to make sure you have back washed the filter. If you have not changed the sand inside the filter in the last 4 years, then you might want to take some time and change the sand inside of the filter.
If you have a D.E. filter on your swimming pool you want to make sure that you have cleaned all the D.E from the grids or fingers. If you haven’t taken your filter apart in a while you might want to so you can remove all the excess D.E powder from the grids manifolds etc. If your filter grids are all yellow, you might want to acid wash the filter as well.
Have Your Pool Chemicals On Hand
Before you start the process of clearing up a green pool you will want to figure out how many gallons of water are in your pool. Next you will want to stock up on the pool chemicals you will need to clean and clear your green pool. Most pools will need chlorine tabs, liquid or powered shock, and off course D.E. powder if you have a D.E. filter.
If your pool is totally green you will want to triple shock the pool with either liquid shock or powered shock. You will want to keep the filter running until the pool is 100% clear. You also will not want to allow anyone to swim in the green pool until it has been cleared up and all of the chemicals have been balanced.
Is Your Pools Vacuum Equipment Ready?
When your pool is green with algae your going to have to triple shock it to kill all of the algae inside of the pool. After you shock the pool most of the dead algae will be filtered through the pools filter system but lots of it will fall to the pools floor. When this happens you will need to vacuum your swimming pool on waste so you can pump the algae out of the pool while you clean it. But before you get started you will want to make sure that your vacuum hose, vacuum disk , vacuum head and vacuum pole are all in good shape and ready to go. If any of the pool cleaning equipment is brittle, old or damaged you may want to replace it before attempting to clean or vacuum the green algae from the pool.
You Will Need To Back Wash A LOT!
Once you have added all the pool chemicals to your green pool you will need to back wash a lot in the beginning. Think of your pools filter as if it was a vacuum and you were cleaning carpet. The more stuff you vacuum from the carpet the faster your vacuum cleaner will clog. The same goes for your swimming pool filter. If your swimming pool is full of debris and algae in the water then you will need to back wash often in the beginning and then as the pool starts to clear and the PPM(Parts Per Million) of the debris in the water becomes less the time between back washes will become longer.
Don’t Give Up , Your Pools Water Will Clear Up
Once you start clearing your green pool it is important that you do not give up mid process because the pool will only get worse. Just stick with it and back wash the filter as needed and also shock the pool as needed. Once you can start seeing the bottom of the pool you will want to start vacuuming the pool on waste so you can remove the excess algae from the pool floor. If you need ant help or have any questions, please feel free to post them below.
my pool water is light green but i can see the bottom. how can i make my water crystal clear again?
Hey Joe,
Just keep on running the filter and continue to back wash the filter when needed,
Also make sure to keep all the pool chemicals in the proper ranges.
ALK: 80 – 120 ppm
PH: 7.2 – 7.4
CHL: 2.5 – 3.0
Let me know if you need any more help,
You could also try a “flock” or clarifier to help group the TDS(Total dissolved solids).
Hope this helps you and others;
~Joseph
Hi,
I was reading about how to clear a green pool but I am not really sure about what back washing the filter means. Can you please explain how to do that?
Thanks in advance.
Hi Yaneisi,
Check out these articles I have:
How To Backwash A Swimming Pool Sand Filter
“Backwashing” your sand filter is one of the most important things you can do to keep your filtration system working properly. You should backwash your sand …
Complete Back washing Guide For D.E. Pool Filters
4) Now that the back wash valve is open and the Diatomaceous Earth has been bumped with the handle you are ready to wash out the filter. …
Please let me know if you need help, or have any more questions.
Joseph
I just purchased and installed a Hayward star clear filter Plus # C17502 and I want to know how to deal with the pressure on the filter. It has a valve with 3 needles (Red, Black and green) but I have no idea about which numbers they should be pointing to, in other words, what would be the correct pressure and how to modify it?
Thanks!
Hi Yaneisi,
Here is how the three needles should work, When your filter is clean you will start the pump, Then you will adjust the green needle to fit right behind the gauge needle. This is your operating pressure, Once the gauge needle hits the red that means you need to back wash. If the gauge needle is in the black area then you could have less flow then needed, which means the pump could be sucking in air etc.
Please let me know if you need more help,
Joseph
It’s really important to rinse the sand filter after it has been backwashed. When removing debris, it is best to run the filter on waste, but remember you are losing water when your system is on waste…work quickly.
To clear up a green pool, shock the pool (and this may take more than one time)and add algaecide unless the shock has algaecide in it. Follow the instructions on the shock and algecide. Once this is done, add a product to settle the algae (flox is the product that comes to mind, but
wal-mart has a less expensive product)to the bottom of the pool in order to vacuum it up on waste. These steps may have to be repeated. You should also check the ph of the pool and you may have to add ph increaser or ph decreaser.
Good luck!
Thanks D Welsh. I am in the process of “fixing” my green pool now. How do I know when to add more shock? I added algaecide and two pounds of shock yesterday and now the water is blue but cloudy. Just backwashed and cleaned the filter. I’m going to let it run until tomorrow and then vacuum it. But, like I said I don’t know when to add more shock or algaecide.
Thanks for your help!
John
I have been battling algae since i opened my pool. I thought I had it under control, went away for a few days, and came back to a full aglae bloom. I went to the pool store and they suggest I add 3 bags of shock with algaecide. (My pool is approx 12,000 gallons, above ground, with a Hayward Cartridge filter) I shocked the pool, and have run the filter for 24hrs. The green has seemed to dissipate, but now the pool water is super cloudy, like milky appearance. What should I do? Keep running the filter? All of my chemicals are coming up in the appropriate ranges (except obviously for the high dose of chlorine). The pump wont burn out from continually running will it? I just want to be able to swim!!
Adam,
Have you ever tried any of “Natural Chemistry’s” products?
I would suggest you get some “Pool First Aid”
Let me know if you need more help,
Joseph
HELP! I still have algae and can’t get rid of it. I have a Hayward cartridge filter which is about 12 years old. I have never had this much trouble with it before. I read your article about clearing a green pool. Of course, I can’t backwash since I have a cartridge filter. Also, I don’t think I can vacuum to waste with my system. My pool is 25,000 gallons. I triple shocked it on Saturday and have run the pump on high ever since with no change. Any suggestions?
Becky,
I would first replace that filter for starters, if you can’t filter the pool its never going to clear,
Then I would triple shock the pool.
Is this an in ground or above ground pool?
let me know,
Joseph
It’s an inground pool. It was built about 12 years ago. We have already replaced the chlorinator and the Jandy valve. We have only have the house 6 years. Should we replace the whole system of just the filter cartridges?
Hey my pool water is clear but the floor of my above ground swimming pool is stained green. Ive tried scrubbing it with my manual hoover and it wont come away. Ive tried shock and algaecide. Any ideas?
Mark,
It sounds like your PH is off, Check your PH level, adjust it and then re brush the pool a day or so after the chemical levels are correct.
Let me know if you need any additional help,
Joseph
I just bought my first house and thought it would be great to get a pool for my son. I have a 24′ wide by 4.5′ deep pool. I’ts green right now. I don’t know the first thing about pools. How often do I run the pump? Why is it so cloudy? When I test it all the readings are ok but the chlorine always reads 0. I use the tablets. Please help
Hi Maggie,
You need to keep the chlorine level around 2.5 ppm
You can do so by adding 3 tablets a week to the skimmer while running the filter for 6 – 8 hours a day.
BUT – Currently your CHLOR is 0 like you said , so you will first need to shock the pool with around 8 lbs of powdered shock or 8 gallons of liquid shock.
The shock will kill the algae and also raise the chlorine,
Once the pool clears in a few days the chlorine tablets will take over keeping the chlorine levels correct.
Please let me know if you have any additional questions or if you need any other help.
Joseph
I am looking at buying a forclosed home with a inground pool. The pool has not been touch in 3 years. It is full with black water. Where do I start on getting it cleaned up?
Thx,
Kim
Kim,
Get the filter starter #1
Joseph
When I opened my pool it was completely filled with algae. The cover had tiny holes which I didn’t know and all the cover water slowly leaked in. Will i be able to get it clear? I added 3 bags of super shock then algaecide. Can now see bottom but it looks brown.
Hi,
Please help us!! We have had a green pool since it was de-winterized. My husband knows he slacked and allowed for to many leaves to get in it before it was winterized but he is pretty sure he has removed all of them with vacuuming or the leaf skimmer. We have spent over $400 in chemicals because the local pool place reccomed all kinds of stuff and none if it did ANYTHING. We followed their instruction exactly and the water did not change! So my husband went back and if course they had more recommendations and gave us a 25% discount because the first stuff didn’t work. Well that was nice, but those didn’t work either! Then we called a local guy reccomended by some friends and he said we needed something stronger, copper algicide so we went and dropped another $50 and some more on shock and he said we should see a difference by te next day. Well, halfway through the next day still pea soup green, I mean can’t see to the bottom green! During all this my husband has backwashed and continues to scrub te sides. We are frustrated and broke and wish we would have just drained the pool at the beginning and started fresh. We both know now that probably would have been a lot cheaper and leas frustrating. Any recomedations on how to proceed would be greatly appreciated!!
I feel your pain. I’ve had my vinyl ag pool for a few years now, and algae is a pain. Here’s a cheat sheet to clear that water.
THE WATER MUST BE BALANCED OR NO AMOUNT OF CHEMICALS WILL DO ANYTHING.
First, get some test strips.
You have to make sure the PH is between 7.2-7.8 and total alkalinity should be 80-120 ppm.
Soda ash (washing soda found in the laundry aisle of your supermarket) will raise PH. If PH is too high, you need muriatic acid to lower it.
2 cups of baking soda pre-dissolved in a bucket of pool water will raise total alkalinity.
When your numbers are balanced according to the test kit, that’s when you add the shock. If it’s granular shock, drop it slowly where the water comes back into the pool (that will distribute it evenly and not just drop to the pool floor). You might need to do this with a few bags’ worth. You’re on the right track when the water starts looking almost milky white and the leaves and things are bleached. Backwash, test, and shock till the water gets clear.
If you get discouraged search “Trouble free pools.” It’s very encouraging.
I can’t seem to get all the flox up despite vaccuming, is there anything else that will dissipate it?
my pool is very clear so thrilled with the results but as soon as turn on the fiter to vaccum, the flox goes everywhere….my in pool Viper does not seem to be picking it up very well? Any suggestons are welcome!