Green water despite FC

[btz30]

Hi all. I've been using the TFP method for 2 years now and never had any trouble. This year, I'm struggling and could use some help. My pool water is persistently green despite adequate FC levels (typically 1-3 ppm). It started off the season clear, but this week went green and won't go away. Last night, I added 10 gallons of 10% liquid chlorine to try and SLAM the pool. FC only got to about 6 after that (I ran out of chlorine and the store was closed, so I couldn't go any higher). In the morning, here are my levels:

• Location - central PA
• Pool type - Fiberglass
• Sanitizer - SWG
• FC - 3.0
• pH - 6.8 (I know this is low - I dropped it to lower my TA and will be aerating to increase)
• TA - 100
• CH - 300
• CYA - 40
• Salt - 3300

I started the season with new filters, and washed them out last night before trying to SLAM. They looked fine. I brushed and swept the pool, and there really wasn't any growth or debris on the floor or walls. They seemed very clean.

PoolMath says only 3 gallon should take me from FC 3 to FC 16 for SLAM, but after 10 gallons I only got to 6 so something must be eating it, right? Should I just keep adding more and more liquid chlorine? It is starting to get pricey, and I'm worried I'm wasting my time.

Any guidance is much appreciated! Thank you!

 

[Texas Splash]

Should I just keep adding more and more liquid chlorine?

Yes. A key compnent of the SLAM Process is achieving and maintainng that elevated FC levle while you inspect & clean the pool each day. The better you do that the quicker the SLAM will work for you. Remember it's a process and take several days. Each pool is different. You may get lucky and get it done quicker, just depends on the severity of algae and owner diligence. But it works.

Hang in there and welcome to the forum.

 

[Texas Splash]

I also want to point out something you said above .....

despite adequate FC levels (typically 1-3 ppm)

Remember, that's pool store and/or generic industry recommendations, not TFP. At TFP we go a step further and clarify that the FC needs to be balanced to the CYA as noted on the FC/CYA Levels. That's very important to avoid algae in the first place.

So once you complete the SLAM Process, be sure to follow the FC/CYA Levels for an algae-free swim season.