Hi Guys,

Ok I was called to come by to see brown blotches which only appear at dawn and dusk.

I've been servicing this pool for around 1 1/2 year and the chems are kept in check. This is Tuesdays report:

============ T E S T R E S U L T S ==============

Pool Equipment = Good working condition.

C.S.I. = -0.06 (Balanced)

Free Chlorine = 4

Chloramines = 0

pH = 7.8

Total Alkalinity = 70

Calcium Hardness = 300

Stabilizer = 60

Salt = 2900

Temp = 86F

Generator Output = 35%

Filter PSI = 20

============================================

The pool is about 22,000 gallons. It was built in 2007. Please click here for pic: http://a6.sphotos.ak.fbcdn.net/hphotos- ... 1218_n.jpg

In the sunlight you do not see hardly any discoloration but when the sun goes in you see it. Today at dusk the discoloration looked much worst.

I know why there is this discoloration. All the contractors on the island mix the Diamond Brite with unclean city water. I have read they highly recommend using clean water to mix otherwise discoloration can happen. All the pools I have seen on the island have discoloration. No one seems to know how to mix Diamond Brite.

My question is:

Does this discoloration get worst over the years and can a good thorough acid washing with pressure cleaner remove these brown blotches? Or at least make it look better?

Thanks.

My questions are; Did it take a few years for the discoloration to appear? If the mix (tap) water is unclean, wouldn't the discoloration show up very soon after plastering? Is the tap water dirty, or does it have a lot of iron content?
If it is the mix water that is the cause, then I wouldn't think an acid wash would help, or at least, the discoloration would reappear in time again.

discoloration shows up after the curing. actually starts to show up like a couple days later but after about 30 days the full discoloration can be seen. This pool had discoloration for years. I met it with discoloration. All the pools on the island have discoloration. some worst than others depends on how dirty the water was. One gated community was built in a swamp and the well water is full of sulfur.

I need to order an iron tester. actually need to order copper and some other testers. The city water is known to have rust in it. you can see it when you fill a pool. we let the filter clean up the rust and then have to backwash. its not much rust but you can see it in the newly filled pool. its yellowish water.

Just to be sure, does it look like rust? Have you tried scraping a vitamin C tablet on it and see if it lightens?

Thanks for the reply. no wouldn't be rust as it can only be seen when the sun goes in or at dawn/dusk. this is telling me its discoloration due to bad mix water. when the sun is out the finish looks great. I'm guessing the quarts in the diamond brite is reflecting the sunlight and so we don't see the discoloration as much. but I'm no expert.

probably is rust. rust from the mix water..and with swg and chlorine over time it should turn rusty.. anyway an acid wash would help I think.

finding a vit c tablet around here is near impossible. I've looked before. only can buy online. no worth it. Its not that bad.