Here's a piece of info I found on a professional pool/hot-tub website, this should solve your question:

"This depends on the size of the spa and the average daily bather load. Water should be checked three time per week for those using chlorine, bromine or a mineral … Read more

Many things, metals are usually melted and made into something else. Newspapers and books are made into newsprint, cereal boxes, paper egg cartons, and ceiling tiles etc. Glass bottles are crushed, melted and recycled into more glass bottles, or used along with sand and gravel in asphalt roads.

Plastic bottles such as milk, shampoo and … Read more