If you are sure it's not algea, then your PH Level is likely low. You need to add PH "Up" to your pool according to the directions, shock it, and brush the liner. You also need to add the maintenance amount of Algeacide weekly.
If you're looking for the plastic pegs for your pool, I would check any store that specializes in pool sales, specifically ones that also do installations. They usually have any spare parts you may need for your pool and are willing to sell them. If that is too expensive then I would check craig's list or the classifieds for anyone selling a pool and see if you can negotiate a price for those parts.
You can use bleach to clean your above ground plastic pool liner. Use one part bleach to two parts water and scrub the stain wearing rubber gloves. Make sure to rinse the bleach thoroughly from the liner before adding more water in.
I do think that you need to change the Filter. It not suppose to be brown. You can buy them at any pool store in your area or retail store that sells pools.
Drain pool and clean with muriatic acid
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the chlorine, it also turns blonde hair green, trust me
You have to treat pool water with pool chemicals and use a pool filter to get and keep the water clear.
It turns white and brittle.
A swimming pool cover is generally a long piece of plastic covering that is generally green or blue. When you pull this piece of plastic over your pool it will keep out leaves and bugs as well as protect against the elements.
Recycling plastic to make useful pool chairs is a great idea. There are many online retailers that sell these chairs including:http://www.resinfurniturestore.com/recycled-plastic-furniture-sets/ http://www.poolfurnituresupply.com/category/4-recycled-plastic-chairs.aspx
your pool filter is turning orange because it is collecting Iron deposits in your water. Iron deposit is actually brown however it turns a really pretty rusty orange color when being filtered.
Epoolshop.com has a thorough catalog of swimming-pool parts for different sizes and types of pool. Their inventory includes such diverts products as filters, pumps, drains, and robotic pool-cleaners.