Build-up on the bottom/sides of my vinyl lined pool

[jlpetrie]

I have a 18' x 36' vinyl lined inground pool and live in Eastern Canada. For the past 2 pool openings, I have noticed a hard build-up in the spring (varies in colour from white to brown on the bottom and part of the sides of the pool) which takes me a long time to remove with a pool brush. This did not happen for the first 7 years of owning my pool. I am getting ready to close the pool for the winter, and have noticed that the same build up is already beginning to form (I last swam in September). It seems a little easier to remove right now so I will scrub it off before closing. Just wondering if anyone can tell me:
- what this is (calcium build-up perhaps?);
- anything I can do to make it easier to remove; and
- what I can do to prevent this from forming in the future.
Thanks!

 

[YippeeSkippy]

Can you provide a full set of test results for your water? I've got a few ideas but need your specifics.
Is your fill water "hard"?
What are you adding to your pool chemical wise? How do you chlorinate??

A signature line (found under Settings) would help answer some basic questions such as type of pool, gallons, how you chlorinate, how you test, what equipment is in use....that sort of thing.

Maddie