Brown Spots

[rgswff]

Everything was going great with the pool as far as balancing the chemicals. The water was looking great. Went on vacation this past week on Tuesday and just returned last night. Before I left, I made sure everything was in line. I then put in a couple of 3" pucks in my IC to provide some chlorine while I was gone. I also new it would raise my CYA about 4ppm but that was fine as I had kept it on the low side knowing I would be taking a couple of vacations this summer.

Numbers before I left for vacation:

FC - 5
CC - 0
pH - 7.5
TA - 80
CH - 200
CYA - 35

Number from after vacation using pucks:

FC - .5
CC - 0
pH - 8.2+
TA - 80
CH - 200
CYA - 35


I get up this morning to brush the pool and clean out the skimmer baskets. I see a couple of small brown spots on the swim out. I think maybe they are dirt but they don't come off after brushing. Any ideas on what they may be and how to get rid of them?

Also, any idea why the pucks didn't keep up the FC?

 

[jblizzle]

Looks like rust stains. Try putting a vitamin C tablet on them and they should lighten/disappear.

Did the tablets complete dissolve? If they were only going to add 4pm CYA, that would only be 6ppm of FC .... and remember a pool looses 2-4ppm of FC to the sun everyday. Sounds like you did not add enough tablets to be gone for 5 days.

 

[rgswff]

What causes the rust stains?

Also, I just opened the IC and the two pucks are still in there. They didn't dissolve. Here are some pictures of my setup. Does anything look wrong? Not sure why they didn't dissolve.

 

[jblizzle]

Metal in the pool. I had a few last year, a couple were from a hair band left in the pool that moved around. Another appeared to come back this year, so wondering if there is a tiny piece of metal that got embedded in the pebbleshean.

 

[Richard320]

The tiniest fleck of metal can do that. When we replaced the common fence with a block wall, somebody broke off a nail head and it landed in the pool. Left a rust spot 1/2" across in only 2 days. Vitamin C lifted it.