Help My Pool Is Very Green

by Sharon

My pool is very green. We have a 24000 gallon in-ground pool with a sand filter. We replaced the sand in the filter about 8 months ago. Four days ago I put 6 gallons of liquid chlorine in the pool. Still green. Then yesterday I put 3/4 gallon of acid the two hours later 3 lbs of shock. Still no available chlorine. Free Available chlorine Low 0 Total Available chlorine Low 0 Calcium hardness OK 250 CYA Low 0 Total alkalinity 110 pH High 8 Acid demand 10 Copper 0 Iron 0 Total dissolved solids 1500 Phosphates 0

It was recommended that I add one bag of powder conditioner in 3 stages or 3 gallons conditioner and 1/2 gallon acid then two hours later add 3 lbs of shock. Is this what would recommend or do you suggest something else. The gallons of conditioner are so very expensive. Thank you for any help you can give me.

Thanks for the question Sharon. Here's what's going on with you pool, according to your readings. Your FC is not holding because you have no CYA/stabilizer in the pool. The CYA helps the FC hold up to 40 - 60% more. Now we need to define what shock is. It's a process of maintaining a high FC in order to kill the algae. This can be accomplished by using grocery store bleach. It's NOT a product you buy. It's marketed as "shock" but in reality it's chlorine.

I can only go on the readings that are provided. Yes it's true that liquid CYA is more expensive, but, it'll get into the pool much faster than granular CYA. Granular is less expensive but it can take a few days to completely dissolve. So there's a trade-off that you need to decide upon.

Another route you can use is buying sodium dichlor which is a stabilized form of chlorine. This is the chlorine that's sold as "shock" but don't concern yourself with the meaningless description on the package. Look for the ingredient sodium dichlor. That's what you want and here's the process for clearing up and balancing your pool. First is to be sure the filter, and filtration system, is running perfectly. Everything cleaned out. You need to check the freeboard in the sand filter. That's the measurement from the top of the sand to the top of the filter. Check your owner's manual or call the manufacturer for that info. Many filters have a freeboard of about 10". If the sand is low simply top it off to the correct freeboard level.

Next is to vacuum the pool very well. This will help get algae and debris out of the pool faster, then backwash. Next is to reduce and maintain a pH level of 7.0 - 7.2. The FC works better at a lower pH. Use 80 oz. of acid around the perimeter and sweep very well. Filter for 10 hours, retest, and make a small adjustment if needed.

Now it's time to add the dichlor. For simplistic purposes, let's say you start this process in the evening. Be careful when using Dichlor as it can get out of hand quickly. For every 10ppm of chlorine added with Dichlor, you'll raise the CYA by 9ppm. Start with 4 lbs. slowly added to the skimmer. If you have an auto tab feeder be sure to take the tabs out and put the dial on "0". What you're doing is adding both chlorine and CYA to the pool. With 4 lbs. of Dichlor you'll be adding 12ppm of CYA and bringing the FC up to 12ppm.

The next morning you'll vacuum, sweep, and add another 4 lbs. of Dichlor into the skimmer. Keep filtering and don't stop.

The evening is the same process, vacuum and add another 4 lbs. of Dichlor. Your goal is to increase the CYA to 30ppm. Once you've done that you'll stop using Dichlor and switch to liquid chlorine for the remainder of the process. Being that Dichlor contains granular CYA it will take a few days for it to dissolve. Don't backwash during this time unless the PSI pressure gets too high. This is normally 15 PSI over the "just backwashed" pressure. Remember to keep the filter ON during this process.

What you've done is maintained a FC level that is high enough to start killing the algae. Using granular CYA will take a couple more days so, again, you need to decide what's best for your wallet.

Once these steps are finished you'll use liquid chlorine. Use 3 gallons around the perimeter of the pool and sweep very well. After 5 days you should be able to backwash and get rid of some of the dead algae that's caught in the filter.

The next morning use 3 gallons of chlorine and sweep very well once again. You MUST keep the FC high, 12 - 14ppm, in order to kill the algae.

In the evening, vacuum, backwash, and another 3 gallons of chlorine. Yes, you are going to go through the chlorine because the size of your pool. Shocking is a process, not an event. The trick is to get AND keep the chlorine above 12 - 14ppm for a period of time. You'll need to manually dose the pool with chlorine to keep it at 12 - 14ppm ppm. Make the adjustment at night, then retest in the morning. Be sure to have the pump running 24/7 and backwash once per day. You can go up to 15ppm, but no higher. Anything after that and you're wasting money and chemicals. You'll know this is working because the pool will go from green to a white/grey cloudy and the chlorine will begin to hold better. First you may lose most, then 2/3, then 1/2, and so on. Once you only lose 1 - 2ppm of chlorine 8 - 10 hours after the last application and the water starts to clear you know the algae is dead. Now it's just a matter of filtering and backwashing once per day. Broadcast the chlorine around the perimeter of the pool and brush well. This will loosen up any algae adhering to the walls and bottom. Shocking a pool isn't adding a bag of chlorine to a pool and expecting it to clear up the pool. Shocking a pool means to kill/eliminate the algae and organic matter. This is done by dosing the pool with enough chlorine to reach a high enough FC level and keeping it at this level to allow the chlorine to kill the algae and organics in the pool.

By this time the water should be either white cloudy or start to clear. What you've done is maintained a high FC level AND increased the CYA to the right level of 30ppm. The range is 30 - 50ppm. You've superchlorinated 5 - 6 times so that's a very good start. Once the FC holds at no less than 10 - 12ppm and the water is clear can you stop this process. This absolutely takes consistency to maintain a high FC level but it's the only way to kill the algae.

If you feel your situation is more complex than this, I do phone and/or SKYPE consultations. It makes things go much faster and many people have found it extremely beneficial, saving them time and money in the long run. All your questions will be answered. I have nothing to sell you so you know I'm not bias. If you purchase a personal phone consult you'll get all 3 eBooks for free.

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Green Inground Pool with Sand Filter

by Reyna Gomes
(Granite Bay, CA)

I have an inground plaster pool with a Superflo PF-50 sand filter. The pool is very green and you can't see the bottom in the deep end. I took a water sample to the local pool store and they gave me a printout with the following readings:

Free Available Chlorine. 10
Total Available Chlorine. 10
Calcium Hardness. 290
Cyanuric Acid. 140
Total Alkalinity. 130
pH. 7.4
Copper. 0
Iron. 0
Total Dissolved Solids. 1000
Phosphates. 1000

We haven't done anything to the pool yet. We just would like a blue pool again.

Hi Reyna. According to the readings provided. You're going to need to do a 3/4 drain and refill. That's the most effective way to reduce it. There's not an affordable chemical on the market to properly reduce the CYA. Your CYA is way too high. Normal range is 30 - 50ppm.

If you've been using any kind of granular stabilized chlorine for weekly chlorination, you need to stop. Only use liquid chlorine. This will take care of 99% of your chlorine needs.

Once you've accomplished the 3/4 drain and refill you'll be able to re-balance the chemicals once again. If you take the pool store's advice you'll be in this for $500 in chemicals and you'll still end up doing a drain and refill.


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Clear Green H20 Help Readings

I have used stabilizer shock treatment the 4 one. My readings are free chlorine bromine zero / 0. PH between 7.8 8.4 alkalinity 240 hardness between 400 and 800 closer to 8 I think. Cya 100 I'm using HTH multi-purpose 6-way test strips.

Permit test results on the site and the chemicals I could find in hand in town I am preparing to add muriatic acid according to the alkalinity chart although I am concerned about lowering the pH too much please help.!! Thank you!!! I have an above ground Bestway pool no sand filter 4000 gal. We are used our well water to fill the pool. Mandie;)

Hi Mandie. First is to STOP using stabilized chlorine for weekly chlorination. The CYA range is 30 - 50ppm. You've gone way over the recommended mark and the most effective way to reduce the CYA is a partial drain and refill. To get the CYA to the desired range of 30ppm you'll need to drain and refill 2/3 of the pool water, then re-balance the chemicals. There's no reason to add any more chemicals until you get the CYA down. Liquid chlorine or unscented bleach will take care of 99% of your chlorine requirements.

For you metals, I recommend Jack's Magic (Pink, Purple, or Blue Stuff) or ProTeam Metal Magic. Dose the pool according to the directions on the bottle. Phosphonic acid is what they both have and what is best for a metal sequestrant.

The reason the pool goes clear emerald green is because of the metals, chlorine, and high pH combination. Once you do the water change, keep the pH lower, between 7.2 - 7.6 and FC at 3 - 5ppm.

Remember if you need more assistance or want your questions answered faster there are eBooks and consults available.

Clear Blue Pool eBook
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