by Kayla
(Kingston, MA)

I have a saltwater pool and it is such a dark color green I can't see the bottom anywhere. I put a little bit of salt in the other day and that helped a little bit but almost barely noticeable.

I have been dealing with green water since I installed the pool in about May. I have had a pool before and have never had so many problems as I do now. I have tried everything the water test has recommended and nothing has helped at all. The other day I shocked it and I watched the water turn an even darker shade of green in about 20 minutes.

I am hoping you can fix this or give me some advice to start to fix this mess.

Here are my stats:
CYA: 94
Tot. Chlorine: 1
Free Chlorine: 1
pH: 7.5
Tot. Alkalinity: 105
Adj. Tot. Alkalinity: 77
Tot. Hardness: 82
Minerals: 2500
Borates: 31
Copper: 0

This is what I was recommended to buy:
93 lbs Mineral Springs Beginnings
1 lb Balance Pak 100
0.25 lbs Lo 'N Slo
24.25 lbs Balance Pak 300

I am so upset and frustrated and I don't know what to do anymore please help me!

Thanks for the question Kayla

Yes I can help and you may not need what your pool store recommended, so here we go. We'll start with what was recommended to fix your problem.

This is what I was recommended to buy:
93 lbs Mineral Springs Beginnings - this is nothing more than regular pool salt. You might be able to get it cheaper somewhere else. Here are some links to help with that. If you have a local feed store, check with them. I got the Y salt pool from our feed store. Just be sure the salt you use is a FOOD grade salt. Very important.

1 lb Balance Pak 100 - sodium bicarb which is the same thing as baking soda. Get some Arm & Hammer or a generic brand from the grocery store for 1/3 the price.

0.25 lbs Lo 'N Slo - Sodium bisulfate a.k.a pH and alkalinity reducer. Muriatic acid is the same, although a bit more dangerous. See which one is cheaper.

24.25 lbs Balance Pak 300 - calcium. If you have a plaster pool it would be good to have the hardness between 150 - 250ppm, otherwise you're wasting your money. If you have a vinyl pool, forget about the calcium. The only function calcium serves in your pool is to prevent the leeching of calcium carbonate from the walls of concrete, plaster or tiled pools. Regular calcium chloride will do the job so don't overpay for something that has colorful or flashy markings on the container. Just ask for normal, average, everyday, run-of-the-mill, no frills and nothing fancy calcium chloride.

Now for the fun part. I can tell you exactly why your pool is green and why the chlorine won't hold. The pH and total alkalinity (TA) are fine, but the CYA/stabilizer is much too high. There's a CYA/chlorine relationship that needs to be met, and this is what many pool store employees don't know or understand.

The chlorine is 7.5% of your CYA and that's 30 - 50ppm. As the CYA increases the chlorine level must increase to keep this relationship. To have a CYA of 94ppm you'll need to keep the chlorine level at 7ppm.

Your chlorine is inactive and causing the algae because of the higher CYA. To keep the chlorine level at 7ppm will require alot of chlorine, something that you probably don't want to do.

The remedy is this - you need to do a partial drain and refill, I would say about a 2/3 drain and refill. There's no easy way to reduce the CYA and no chemical. A water change is needed. By doing a 2/3 drain and refill you will, in effect, reduce the 94ppm CYA down to about 30ppm, which is in the right range of 30 - 50ppm.

You can dump 100 gallons of chlorine in the pool, and spend thousands of $ on algaecides, flocs, and clarifiers, and it may clear it up for a little while, but I can almost guarantee your pool will turn green again for the reasons stated. I've been doing pools, and cleared up hundreds, since 1999 and have seen this many times.

Once you do a partial drain and refill, it will be time to re-balance the chemicals. I strongly suggest taking the readings on the fill water. This way you know what's going into the pool. If the TA of the fill water is 200ppm, there won't be any surprises because you'll know the TA needs to come down to 80 - 100ppm. Same with the pH and hardness.

I have no idea what the readings will be once you do a 2/3 drain and refill. When you get to this stage you can email back and we can go from there. The pH might be very high or low, along with the hardness and alkalinity. After the refill, allow the filter to run for 24 hours, then do a full test on the water. This will show what course of action to take. Please don't get "pool stored".

If you would like personal assistance, I do phone consultations for a donation of your choice. It makes things go much faster. If you choose to not go that route, we can correspond by email.

Contact Me


Hope this helps and have a great Summer.



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Jun 06, 2015
Re: Clear Green Water
by: Margaret

Thank you for you're advice. I did everything you recommended,but used what products were available to me. HTC Metal Control helped,but pool is still clear green. Added the acid and liquid chlorine. Changed the filter twice a day,the filter and the water in the fliter were a copper color and super dirty. Numbers are:

Thanks for the follow up. The pH is fine at 7.8. for salt pool a pH level of 7.6 - 7.8 is good. The reading that is a concern is the CYA. The first reading was 30 - 50ppm, or maybe 100ppm. The newest reading is now 0 CYA. You need to be sure what the CYA level is. Some salt pool owners choose to not use CYA due to the chlorine cell's ability to constantly produce chlorine. I'm of the opposite opinion that all outdoor pools should have at least 30ppm of CYA, maybe not tabs, but some CYA. I'd encourage you to do another test to determine the actual CYA level. Your pool store is able to test for it.

As for the emerald green water I'll give the same advice to look for Jack's Purple Stuff. It's HEDP and is the best for your issue. You need to dose your pool per the directions on the bottle until the metal issue is finished.

Jun 02, 2015
Clear Green Water
by: Margaret

I havr an Intex 20ft X 4ft Ultra Frame Above Ground pool With a Intex Crystal Clear Salt Water System. Filled it with 6400 gallons of city water and the rest with our well water. After using 1 time it turned clear green. I used HTh Ultra Complete Shock, 1 bag, and the pool is still clear green. Here are my numbers using HTH 6way test strips
TH 200
FC/Bromine 10/20
PH color between 7.8 and 8.4
TA 240
CYA color between 30-50 and 100
Salt at 3470
We do not have the option of draining it and starting over -drought-
What's the next step?
Thank you

Thanks for the question Margaret

The first thing is to get a good test kit, the Taylor K-2006. Test strips are good but are prone to inaccuracies. The CYA is what I would be concerned about. There's a HUGE difference between CYA of 30ppm and CYA of 100ppm. The first is fine. The 2nd requires a partial drain and refill. Without knowing the exact number I can't tell you which one to do. Unfortunately there's no chemical on the market that will effectively reduce the CYA.

The reason your pool turned an emerald green is because of the metals in the water. You need to get a good metal sequestrant. I recommend Jack's line. You can see if Walmart has it. Amazon is a good choice as well. A metal sequestrant does not remove metal from pool water. It holds it in solution until it can get filtered. Then you backwash the metal out. Because metal sequestrants break down over time and get filtered and backwashed out, you will need to add a bottle once per week or when your pool needs it. Follow the directions on the bottle.

Let's say the CYA is fine, between 30 - 50ppm. First is to get the pH and TA down with muriatic acid. The pH should be between 7.0 - 7.2. Chlorine works better at a lower pH level. 12 oz. per 10k will reduce the pH 0.2 and TA 10ppm. Yours is a smaller pool so it won't require much acid at all. Start with 20 oz. around the perimeter and sweep well to mix it up.

Be sure your filter is working properly. Is it a cartridge filter? If so it must have less than 2000 filter hours on it to be effective. You cannot clean dirty water with a bad filter. If you're unsure as to the hours it's best to get a new one.

Next is to NOT use HTh Ultra Complete Shock. It's calcium hypochlorite which has a pH of 12. You're reducing the pH with acid but then raising it back up with HTH. Only use liquid chlorine to shock. Use 1 gallon around the perimeter and sweep well. We need to define our terms, and this is very important to understand. Shocking is a process, not an event. It's not something to buy, it's something you do. The trick is to get AND keep the chlorine above 10 - 12ppm for a period of time. You'll need to manually dose the pool with chlorine to keep it at 10 - 12ppm. 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 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.

Once again, what I've just described is for a CYA of 30ppm, NOT 100ppm. CYA of 30ppm is fine while 100ppm requires a 2/3 drain and refill.

The salt level seems to be fine but be sure the cell is OFF during this process.

If you feel your situation is more complex than this, I do phone 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.

Pool Consultation

Swimming Pool Care eBook

How To Clear Up A Green Pool eBook

Hope this helps and have a great Summer.


Apr 30, 2015
Salt Water Pool Clean Up
by: Anonymous


Thanks for the question

First is to remove as much debris as you can using a leaf rake. Then be sure your filter is running and in good order. Without knowing the kind of filter you have I can only make general statement i.e. if the cartridge is torn or has more than 2000 filter hours it needs to be replaced.

Next is to get all of the chemical readings. You need the actual numbers which you can get using the Taylor K-2006 kit or go to the local pool store. Be sure the water is topped off, between 1/3 - 1/2 up from the bottom of the skimmer. Remove any plugs in the skimmer and returns.

Again without knowing your chemical numbers it's hard to say what to do first. The pH and TA may be high or low, etc...

Be sure the pH is down to 7.0 and shock the pool with liquid chlorine. It's 1 gallon to increase the FC 10ppm per 10k gallons. Check the CYA and adjust if needed. The range is 30 - 50ppm.

You probably need to shock a few times to kill the algae. Keep filtering 24/7 and clean the filter once per day. At the very end of the process you can use a clarifier to help with the filtration process.

If you feel your situation is more complex than this, I do phone consultations for $37 donation. 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.

Pool Consultation

Hope this helps and have a great Summer.


Feb 22, 2015
BioGuard Mineral Springs Beginnings & Balance Pak
by: Kayla

Robert you are a life saver. I will definitely follow your advice!!! You are the best thank you thank you thank you!!!!!


Sep 04, 2012
Green Salt Water
by: Anonymous

Algae killer, baking soda, vacuum. Algae killer will kill algae, baking soda will make it sink to bottom. Then vac.

Bleach will help clear the water takes about three days, use powder.

Thanks for the comment, however, you need to be more specific. What kind of algae killer are you referring to and how much would be needed? How much baking soda would one need per 10,000 gallons? Baking soda raises both the pH and TA so how would you take care of any increase? How much acid would you use per 10,000 gallons? Are there any sid effects?

And then there's the bleach. Although bleach can chlorinate pools, the comment fails to say how much would be needed.

What does "use powder" mean? Powder algae killer?

You may know, but when giving information or commenting it's best to be specific and give detailed instructions because others may not know or understand.



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