How To Get Rid Of BLACK ALGAE In Your POOL

Swim University makes pool and hot tub care easy for millions of homeowners. Each year, we continue to help more people with water chemistry, cleaning, and troubleshooting. We know taking care of a swimming pool or spa can be difficult. And it’s hard to find a trusted source of information. This is the reason we created Swim University.

It’s bad enough to discover green algae in your pool. But black algae? Get ready, because you have some serious pool cleaning to do. And no one should swim in your pool until it’s gone. The good news: it’s totally possible to kill black algae. Here is a step-by-step guide on how to get rid of black algae in your pool for good.

⏰ Timestamps:
00:00 - Introduction to How To Get Rid Of Black Algae
00:24 - What Is Black Algae And Why Is It In Your Pool
00:53 - Is Black Algae Harmful?
01:11 - What Does Black Algae Look Like?
02:14 - How To Kill Black Algae
02:54 - Step 1. Clean Your Filter
03:19 - Step 2. Test And Balance Water
03:52 - Step 3. Brush Your Pool
04:21 - Step 4. Scrub Black Algae Spots
05:08 - Step 5. Brush Your Pool Again
05:19 - Pool Care Course
06:03 - Step 6. Quadruple Shock Your Pool
06:49 - Step 7. Run Your Pump
07:00 - Step 8. Brush Your Pool AGAIN
07:19 - Step 9. Clean Your Filter Again
07:43 - Step 10. Shock The Pool Again
07:56 - Step 11. Run Your Pump Again
08:07 - Step 12. Brush Your Pool AGAIN!
08:19 - Step 13. Test And Balance Water
08:31 - Step 14. Keep An Eye Out For Leftover Black Algae
08:55 - How Do You Prevent Black Algae?

[elmamo]

That "good luck" at the end was very heartfelt.

[jimschuler]

I've been telling the local frogs to wash their swim trunks, but they just croak at me before jumping in.

[kurtvandelden]

One Tool: Pressure Washer. For a Gunite pools, jump in and get close with the wand tip, wash the walls, remove the black spots.. Then shock with chlorine. Works every time.

[drdrew]

This is too much work. How many bags of concrete to fill in a 15, 000 gallon pool?

[christ]

Hi there, great video and thanks. We struggled with black algae but using chlorine tablets like chalk and rubbing the black dots and patches away works absolute wonders. I didn’t find the extra brushing or using an algae brush to be as useful. Also an algae brush can scratch your marbelite and there is no need to crack the chlorine tablet in half just use it whole. Cheers 👍

[gailhardy]

We have an above ground 18x33 vinyl pool, I kept hearing black algae does not form on vinyl above ground pools, your video does show above ground pool in this video...I have tiny black spots forming that I scrub, and most come off with some effort...I guess I need to follow this video process and see if that helps. Thanks for the video.

[TheBaltherion]

Thanks! I have a black algae problem at one of my pools.

[THEJavelinX]

Pressure washer works well to scrub it as well, in fact, it works the best. Soooo much easier than scrubbing

[SteveWarner]

I honestly didn't think this would work, but it did. I have a pebbletec pool and the black algae was just stuck in the grooves. I had double shocked the pool and brushed it in the past but it made no difference. But I followed the steps here. 4x shock. Power wash everything I could reach without getting into the pool on day 1. Brush 2 or 3 times per day. Clean the filter 2x per day. Double Shock the next day. Brush 2 or 3 times per day. Clean the filter 2x per day again. I ended up buying a whole new filter along with Ph Down and Alkaline Down to keep the levels within reason. Normal shock on day 3. Same process of brush and filter. On day 4, there was no active chlorine in the pool. But the algae was 80% gone. So I repeated the entire process from the beginning all over again. Having a new filter really helped as it kept the circulation going. Going into day 6, I did the normal shock. Day 7 there was no active chlorine left in the pool, but there was no black algae, just what appeared to be "stains.: So I bought a giant tub of chlorine pucks and threw 2 in the skimmer basket, 2 in the pool, and 6 in the automatic feeder. Continued to brush 3x per day. Clean filter 2x per day. Day 8 the water was clear. It's day 9 and the pool is now crystal clear. The "stains" are gone as well. It was a lot of work, but far less expensive than draining the pool and acid washing it, which is what I thought we'd have to do. Thanks, Swim U!

[anmolgupt]

Thanks! That's helpful. I had black algae in my pool and I have been working my a$$ off to remove it :-).

[jonkocen]

Basically to get rid of any type of algae from a pull over shock your pool, brush, run the pump for 24 hrs, then clean the filter, repeat as needed

[CraigOffTask]

I have a pebble tech pool with a salt system. The pebble tech material seems to breed this stuff. What type of a brush should I use on the pebble? I don't think a metal bristle bush would work for my material. Also, I've heard you say not to use cal-hypo shock for a salt system pool. What shock should I use?

[sutherlandws]

What are your thoughts on using the SLAM method for removing black algae. It is not unlike what you described, but requires keeping the pool chlorine above a target level (based on the current CYA levels, which, for my pool, was 30, so a target chlorine level of 12 ppm) for several days or even a couple of weeks, all while brushing 2-3x daily. At least that is what I have read. I have been doing this for almost 10 days now. I did not use the chlorine tablet scrubbing process, but did see it mentioned, as well as some sort of tablet holder to help in the process. My issue is that, after the SLAM process, I still have residual stains from the black algae and want to remove those. I ALSO appear to have significant metal staining (steps, pool wall where hot tub flows into pool). These are brownish. I ALSO noticed signifcant additional staining during the SLAM process. Not sure what that is. Finally, a reasonable amount of the black algae is on the pool bottom, or in the deep end walls near the bottom, making it very difficult to reach. I have been using the algae brush for these, but it is hard to apply much pressure.

Any suggestions would be appreciated.

[ithirstyforknowledge]

You never mentioned Algaecide. Is it not necessary?

[eddiksa]

How do you get at the deep end to scrub? Go in with snorkel to scrub? Would the chlorine be dangerous in high concentrations? How about letting a chlorine tab lay on it and move every few hours?

[Ohlawd]

This must be not in FL because in FL the ideal ranges vary due to the harsh humidity in the summer.

[horacelee]

I have a 15K gal inground pool that has Two Skimmers .I don`t have a suction side cleaner yet so I have to use one of the Skimmers.Which skimmer should I use for vacuuming or does it matter and during normal operation should both skimmers & drain be wide open when pulling water?

[emilyrodriguez]

How can I remove black mold from my above ground pool that’s has a vinyl lining?

[tomnguyen]

Lol I would have to quit my job and be a full time pool cleaner!!!

[rebeccahill]

Hello, I have an inground 30'x40' vinyl liner (over cement) salt water pool w black dots in it which im assuming is black algae. I saw 1 response for an above ground vinyl liner however there was no return reply. Is the removal process for black algae the same as a gunite inground pool? If not could u please give me a step by step process of it. I'm no pool guru so PLEASE be specific as I'm the teacher mom home during the summer taking care of the kids so needless to say poolcare is NOT my forte'😁 thanks in advance!!!!