Pool Green and No Alkalinity

by Stephanie
(Inverness, FL)

I have been working on this pool for a month, never had an issue with not having clear water.

I have shocked multiple, multiple times, added at least 25 lbs sodium bicarbonate, 2 gals liquid chlorine, kept a floater full of 3" tabs, new cartridge filter (cleaned a few times already), algeacide and clarifier.

Today at the pool place, these are my readings:

Chlorine Free-1.6, Total 2.3, combined .7
pH UNR6.5 (unreadable?)
Alkalinity - 0
Hardness - 60 ppm (vinyl 24 ft round above ground pool)
Cyanuric Acid - OVR150ppm
Sand, Cartridge, DE Filter - cartridge

Pool place gave me 2 bags of shock, told me to put both in tonight as well as the remainder of the bottle of algeacide I bought from them on Saturday....clean filter and continue to run pump.

Any other suggestions?

Thank you


Thanks for the question Stephanie

My first suggestion is to run, don't walk, from the guys at the pool store. You've been what is called "pool stored", to put it nicely. Be nice to them because you need your routine chemicals, but be weary of their advice.

Thanks for the readings, and here's what's going on. First is the CYA. Normal range is between 30 - 50ppm. Anyone who has ever worked on a pool will tell you that 150 ppm is way too high. The reason for its increase is the use of Trichlor tabs, which are a combination of chlorine and CYA. As you use them they will chlorinate your pool, but also consistently dose your pool with CYA.

Or you've been using Dichlor chlorine which is a stabilized form of chlorine. NEVER use this as your weekly pool maintenance chlorine. Only use liquid chlorine, bleach, or in some cases calcium hypochlorite (granular chlorine). Dichlor should only be used when the CYA is a bit low, below 20 ppm. Use it to quickly raise the chlorine and CYA. When the CYA gets to 30 ppm, stop using it and go back to liquid chlorine.

There's good news and bad. First the good. You can have a perfect pool. Now for the bad. You've wasted alot of time and money, but you already know that.

The reason the chlorine can't hold is because there's a relationship between the free chlorine (FC) and CYA. The chlorine needs to be 7.5% of your CYA. When you have a CYA of 150 ppm, you need to run the chlorine at 11 ppm for it to be effective.

They see a green pool and their first order is to shock it. They MUST look at the readings and know how to decipher them.

There's only one way to quickly and effectively reduce the amount of CYA and that's a partial drain the refill. If you haven't put the shock in yet, please don't do it. You're wasting chemicals, time, and money.

You need to drain 3/4 of the water, refill, and FILTER for 24 hours, then re-test everything to know where you are. Now, your CYA is 150 so if you drain 3/4 of the water you'll remove 113 ppm and keep about 37 ppm, right in the target area.

You're adding alot of new water and I don't know what the alkalinity and pH of the water right now so the readings you have won't match the new fill readings. That's why you FILTER for 24 hours and re-test everything.

I've received hundreds of questions, exactly like yours and they start out with "the guy at the pool store said". Here's a link to a woman I helped in Chicago. Same kind of issue. About 2 weeks and $60 later her pool was perfect without clarifiers, flocs, phosphate removers, tones of expensive algaecides, etc...

High Phosphates Over 1000 & Cloudy Water

There are many others but I like to use this one.

Sorry to tell you but this is the only way to get your pool back. Do the above and give me the new numbers.

Hope this helps and have a great Summer.


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Low Total Alkalinity and PH

by George
(New York)

I have a 10,000 gallon fiberglass pool. Been having this problem for a long time. Had a pool service, talked to pool techs and everyone has their own solution, but none were ever effective. For years I had trouble with staining and algae. To remove stains I had to purchase ascorbic acid (vitamin C) which is pricey. I was in a vicious cycle. The water turned cloudy quite often so I would shock the pool. Soon thereafter brownish staining would appear on the floor of the pool. I added the acid and all was fine until a few days later the water got cloudy, then I added more shock then the stains.

Total alkalinity was perfect but difficult to raise PH to the proper level. For some strange reason starting last year, the water has remained crystal clear, filtering 4 hours instead of 8, using very little chlorine. But I cannot get any ph or total alkalinity reading. This had caused the water to acquire a sour taste and I am concerned that this will cause damage to filter, heater, etc.

Everyone wants me to do the baking soda thing. I am afraid that once I get the total alkalinity back I, will be susceptible to the pool staining cycle that I mentioned above.


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