Green pool

[NatashaLea]

Hello! I’m new to TFP but have been reading your forums for years. I maintain my pool myself and have had great luck with minimal effort in years past, but am struggling this year with a consistent green pool. I’ve purchased my Taylor kit and am awaiting delivery, but in the meantime received a pass from the local pool store regarding chem balance. Judging by the photo, does this appear to be algae? It’s been at shock level for weeks and it usually doesn’t take but a few days to turn blue. CYA is around 70 (per the strips and pool store). Just purchased new cartridge filters and running 24/7 for weeks now. Any advice in the interim?

 

[Texas Splash]

It might be algae, but that's an interesting clear hue of color. By any chance are you on a well? If not, have you used copper-based pool products in the past like algaecides, mineral packs, or products with the word "Blue" in them? Is there any staining around the pool ? How do you chlorinate on a daily basis. Also, don't forget to update your signature with all of your pool and equipment info. It will help us later.

 

[Grayman43]

By at shock level do you mean you followed the slam process? What are you using to test your FC levels ? I had this problem last year and I just had to follow the slam process . Don’t skip steps. Thanks

 

[IceShadow]

More importantly - you can't really do a SLAM without doing your own testing because without knowing your CYA levels it's a crapshoot, and you can't reliably measure FC over a certain level with anything but the FAS/DPD tests.

Texas Splash's question about metals is a good one, but other than that you need to get your test kit in so you can properly SLAM. Until then just add 5ppm of FC per day via liquid chlorine to try and keep it from getting worse until the text kit is in.

 

[NatashaLea]

Ok, test kit arrived and here are my results...

FC 4.2
CC .4
PH 7.8
Alkaline 130
CH 200
CYA 100

I know from reading TFP forums that I will need to drain part of the pool. Is there an alternative? We are on a well and have drained the pool to the first step twice already in the past two months and am afraid of burning up the pump.

Any suggestions on the amount I should drain, how to go about balancing and next steps afterwards would be greatly appreciated!
Thanks so much!

 

[IceShadow]

You may need to do a diluted test on your water for the CYA test. Mix half pool water with half tap water and test that. Multiply result by 2 and let us know what it is.

 

[NatashaLea]

Hello We ended up draining a little more than half the pool. The great news, it’s sparkling blue and clear!
Here are the results of my new test. Please let me know your thoughts on which to adjust first.
FC 6
CC .5
PH less than 7 (below level on test kit)
Alk 100
CH 120
CYA 45

 

[IceShadow]

You have to round the CYA up - it’s a logarithmic test so you can’t extrapolate between the lines. Consider your CYA to be 50.

Aerate the water a bit to get the pH up - if you have water features run them, aim the jets up to break the surface, etc. Your TA should push the pH up with aeration.

Maintain the FC at the right level on the FC/CYA Levels and once the pH is up enjoy the pool