This is my first post with this group. I had stains appear during the winter. Pool center said high in minerals. As a result of several conversations, we disconnected the ozone system and Nature2 system. Changed the sand. Water is clear but stains won't leave. When I add shock the stains go to a darker gray or black. Won't stub off. Over 24 hours, darkness fades, but stains are still there. I am truly stumped. Am I fighting algae or metals or both? Getting different recommendations from pool centers. We have a leaf problem in the winter, which we skim up. Pool runs all year long. This is the first time we have had this problem in 5 years. Even the return gets have turned a dingy yellowish brown. I hope someone can help me. Thanks
Fighting stains that turn black after adding shock.
- Thread starter drgarymartinez
- Start date
Welcome to TFP.
A couple of things to try:
Rub a vitamin C tablet on the stain. If that shows improvement you probably have a metal issue
Rub a chlorine puck on the stain. If that shows improvement you are likely dealing with algae.
How are you chlorinating your water? And posting a full set of test results will help us help you.
A couple of things to try:
Rub a vitamin C tablet on the stain. If that shows improvement you probably have a metal issue
Rub a chlorine puck on the stain. If that shows improvement you are likely dealing with algae.
How are you chlorinating your water? And posting a full set of test results will help us help you.
Tried the test you recommended. It seems that this is algae after all. Tested the water: total alk:101.00ppm; pH: 7.30; temp: 89.1; Cal H: 203.00 ppm; FC 2.53 ppm; Stab: 75.00 ppm. What are your suggestions?
Hopefully you tried the Vitamin C first. It lifts metals but not organics. A Trichlor puck will lift either. So you might have just given yourself a false positive for organics when it's metals. Vitamin C will work fast -- check out the picture here: Yellow Stains
If it is organic, then time and chlorine will lift it. You just have to maintain the FC/CYA ratio and be patient. I suspect it's metals because it darkens with chlorine.