Relatively new pool is green and has elevated CYA

[Adiharce]

We have had our pool since March and since May I have been struggling with the pool turning green (not swamp green, but not pretty clear water).
I tried using bleach for a week, but was having to add so much that I have gone back to chlorine tabs, which I know lead to higher levels of CYA. Would like to go back to something without the added stabilizer, but not sure what steps to take. I am new to the TFP method and would really appreciate some guidance.

Here is my info as well as I understand it.
In ground plaster pool with a spa. Sand filter.
17,000 gallons.

Numbers yesterday were:
FC: 5.0
CC: 1.0
TC: 6.0
CH 275
TA: 130
CYA:90
PH: 7.8

I added 22 oz muriatic acid per pool math instructions. 8 hrs prior to testing yesterday I added a bag of shock that we had on hand.

Today's numbers:
FC: 3
CC:1
TC 4
PH: 7.5
CH: 300
TA: 100
CYA: 100

I have small patches of green algae on the limestone steps and seat in the pool. No algae in the spa. The algae scrubs off easily with a wire brush.

Do I need to SLAM? If so can someone please lead me to the link for step-by-step instructions? Is this going to be an ongoing problem due to CYA levels? Also, why is CYA level so high after only 4 months of pool operation? Can the tablets cause that much build up in 4 months. I am hesitant to drain the pool at this point as we are in drought restrictions and I believe will incur a hefty surcharge if we refill. I would appreciate any suggestions, guidance, help! Thanks in advance!

 

[duraleigh]

Welcome to the forum.

Let me comment first that if your pool has algae, chlorine is the cheapest way to fix it and keep it from coming back. There is no substitute and bouncing back and fort5h "trying" different things will only cost you more money. There is no escaping that fact.

That said, I would suggest you start by reading "The ABC's of Pool Water Chemistry" up in Pool School. That'll get you some basics and it should provoke you to ask a few questions.

Ultimately, you will have to SLAM the pool but you really need a better grasp of what's occurring in your pool before you start.. Keep us posted.