Light green tint and a little cloudy


Bronze Supporter
Oct 26, 2014
Pearl River, Louisiana
I lurk on here quite often and soak up a lot of knowledge. Thanks!
Here is a problem I don't understand and ask for any guidance. Here is the short story. My pool has been clean, clear and balanced for months but is now starting to turn green. F.C has not gone below 4 since late spring. I am thinking of doing a SLAM but not sure why I have algae with chlorine staying over 4 and usually around 5.

Latest test results: 9/24/18
Salt 4200 PPM
FC 4.5 (only by SWG)
PH 7.6
T.A. 60
CH 70 (Does that really matter in a vinyl pool?)
CYA 70

All filters have been cleaned and were not really that dirty.

Info that may or may not have anything to do with my problem.
Big party 2 weeks ago. Many pool users all day.
After 12 yrs, I realized this spring I need to raise CYA to 70 or more. It has usually been low or non existent.
My PH has been being high for the past few months. I tried the box store powder to lower PH but it never would come down. About a month ago I finally went to M acid which worked a little too well which brought it down to 7.0.

Anyway, I ran out of F.C. test supplies today and may start SLAM after I get re-supplied.

Random question. Can test supplies go bad? I wonder if my F.C. test supplies are giving bad results.

Please let me know if you have any thoughts.



Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
Tucson, AZ
Yes test reagents can go bad after a year or so, faster if not stored in a dark climate controlled location.

Heavy use likely dropped your FC too low and allowed the algae to start. Always a good idea to bump the FC up before and/or after heavy use with bleach (no one would even notice the higher FC levels).

Sounds like time for the SLAM Process process.