Stubborn Green pool need advice

What test kit are you using?

To get an algae-free pool, you have to follow our SLAM Process step by step without shortcuts. This process can take days or weeks.

Then, adopt TFP pool care methods...

What is your CYA level?

So you added stabilizer...with a CYA of 90.

That's a mistake, as now you need nearly 8 chlorine every day to stay balanced.

Draining is good, but don't add anything except some chlorine until you get filled and tested.

The reason you are going green is an imbalance between your Free Chlorine, and your stabilizer.
Stabilizer is a bad label - CYA essentially 'binds' with the Chlorine to slow down the degradation due to UV from the sun, but in doing so, it makes it less 'available' to kill off the algae and such in the water. It does nothing to stop the chlorine being used up by killing off nasties...think of it as Chlorine-Sunscreen. Hence, if you add stabilizer, you have to add free chlorine to keep them in balance, so there is enough Free Chlorine available to kill off the nasties in a reasonable time, and the rest is sort of in reserve... That, at the heart of it, is the TFP method.

In order to correctly balance your Free Chlorine and CYA (Stabilizer), you need a good test kit. We recommend one of these : Test Kits Compared.

With those in hand, you should then be able to keep your CYA and FC balanced, and you'll never go green again.

Bear in mind, the UV from the sun only stops at night - so if you don't keep adding Chlorine, it will get used up and you'll head back toward Green pretty quickly. Typically you can expect to see 2-4ppm loss per day, which in 4400 gallons is about 2 cups of 12.5% Liquid Chlorine each day.

If you're adding Dichlor (powdered shock) or Trichlor (the little pucks) then you're also adding CYA/Stabilizer back in again...and you'll be back in the same cycle.

You really need to read this - Pool Care Basics

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