Home How-To & Tips How to Clean a Green pool or spa

How to Clean a Green pool or spa

Green Swimming Pools are not fun. Here are our Green Pool Service Tips on How to turn a green pool blue again. A nice blue swimming pool is all we’d ever want to see in our backyard, and have never been a really big fan of the “pond look” so, let’s learn how to fix that.

how to clean and clear a green swimming pool

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WHY IS MY POOL GREEN?

A pea-soup pool can be the symptom of a number of other factors. You may need to clean your pool filters, your pool pump impeller might be clogged, or maybe it rained for 3 days straight – among other reasons a pool can turn green.

Short Answer: Something about your chemicals or equipment has caused bacteria to grow out of control in your pool.

See Related: Why is my pool always turning green?

HOW GREEN IS YOUR POOL?

Since there are varying stages of a green swimming pool, there are a few methods of handling this type of swimming pool water condition.

Algae & bacteria growth is what causes your pool to look green and murky. Which means that something has gone wrong with either your pool chemicals, or the pool equipment – but sometimes forces of nature.

Water is clear-green but I can see the bottom

You are in the best shape to quickly turn the pool blue again. Light green water and you can still see the bottom means algae is in early stage growth.
Water is clear-green but the walls are slimy

This stage of algae growth is going to take a little bit of labor, but you can usually turn the pool blue again in about 2 – 3 days.
Water is pea-soup I can’t see anything

In this situation, it might be best to drain most or all of the pool water and re-fill.
Water is dark green like stagnant pond

This is an extreme situation and an obvious health concern. As above, this will certainly require draining the pool and re filling, but may also require pressure washing or special disinfectant treatment.

WHAT DO I NEED TO CLEAN A GREEN POOL?

TOOLS

- pool pole
- pool brush (Nylon & Metal combo for gunite, nylon only for fiberglass & vinyl liners)
- pool net
- pool vacuum head & hose

CHEMICALS

- Sodium Bromide 99%
  We recommend: Jack’s Magic “The Yellow Stuff”
- Stabilized Pool Shock
  We recommend: Regal “Dy-Chlor II”
- Regular Pool Shock
  We recommend: Regal “Re-Fresh”
- Muriatic Acid for pools
  We recommend: Home Depot “2×1 GAL Muriatic Acid”

See Related: How to shock a swimming pool

STEPS TO CLEANING A GREEN SWIMMING POOL

This is probably going to take 2 to 3 days for minor, and 3 to 5 days for major green pool situations. The overall method will be to determine what caused the green pool problem in the first place, kill the current bacteria in the pool, collect it all to the pool filter, clean it all out from the filter system, and re-balance the pool chemicals.

Steps below are for minor to moderate green pool conditions.

TIP: You need to know how many gallons your pool holds.
how to measure a swimming pool for water volume calculation
Find out here Pool Capacity Calculator

STEP 1: (Day 1) KILL-OFF THE ALGAE & BACTERIA

1. 1. Begin by brushing the pool in all of the visible algae spots you can see, brush as hard as you can.
  2. Use the granular regular pool shock first (calcium hypo-chloride) at 3-lbs per 10,000 gallons.
  3. Wait 2hrs time then add the Jack’s Magic “The Yellow Stuff” per directions.
  4. Wait another 2hrs, then brush the pool again.
  5. Set the pool pump timer to run continuously for the next 24 to 48 hours.

By the next day the pool should be showing signs of clearing up, if not already. But there is one thing – your chlorine levels are probably at zero and the pH has probably increased, so let’s fix that.

NOTE: (Sodium bromide will cause the shock to react very quickly reducing free chlorine to 0-ppm, and the shock will add a bit of calcium thereby increasing pH levels a little.)

STEP 2: (Day 2 – 3) Re BALANCE POOL CHEMICALS

All of what you have brushed around the pool will begin to settle, and can be vacuumed when the water is clear again, for now you need to monitor and keep the chemicals back in normal range.

1. If chlorine is reading 0-ppm, then it’s time to use the Regal Dy-Chlor II per directions to raise free chlorine.
2. Make sure that your chlorine feeder is working and is full with the output set to 100%.
3. Check the pH level, and if high – add muriatic acid as needed.
4. Now, just run the system until the water is clear allowing for the debris to settle for vacuuming later.
5. Take note of the filter pressure while the pool is running, if the pressure seems high see our post on how to clean the pool filter.

Ideal Chemical Ranges:

pH = 7.4
ChL = 3.5 – 5ppm

TIP: Our goal is to catch all of the dead algae & dust inside the filter so that it can be removed from the total system when the filter is cleaned.

STEP 3: (Day 3 – 5) TOTAL SYSTEM CLEAN-OUT

At this point, the chlorine levels should be holding within a range of 2.5ppm to 4ppm and pH at about 7.4 – and you should be able to see clearly through the water. It’s time to clean everything up, starting at the pool and working back to the equipment.

vacuum a green swimming pool

1. IMPORTANT: do not brush before vacuuming! Using the pool vacuum head & hose vacuum the bottom of all the pool / spa. (This is hopefully going to catch all of the crud that settled to the bottom and get it all to the filter.)
  TIPS: If you have major debris like sticks, branches and leaves in the bottom you may want to use a Leaf Master – don’t run all that stuff into the pool system!
2. Only after you have vacuumed all that you can, THEN brush the pool.
3. Take this time to clean out the in-pool cleaner if you haven’t already.
4. Time to service the pool equipment. Everything is now inside of the filter, so you need to clean it out. How to clean your pool filter: Here
5. Clean out the pumps strainer baskets (all of them).

From here, there may be a little dust, maybe a hint of cloudiness, but that should be from vacuuming & brushing. Simply run the pool continuously (with the auto pool cleaner on) for another 24hrs and you should be looking really good by the next day or two.