Almost all pool heaters use a copper heat exchanger (looks like a radiator; water flows through it; fire heats the outside = hot water). Salt water or fresh water, all pools have chlorine. Over time, chlorine corrodes copper. (As a pool service provider, I have never seen rust stains caused by a copper heat exchanger: the most common causes of rust stains are iron based lawn fertilizer in the pool and metallic objects resting on the bottom too long) Copper will, however, eventually leave blue-green deposits on the plaster surfaces. While I haven't yet seen one, it is my understanding that one or more of the larger pool equipment mfrs. makes a heater with a titanium heat exchanger which does not corrode. Check with Hayward, Pentair, Jandy, etc., but expect to pay big bucks.
Deposits from water heater, usually whiteish colored.
Most water heaters have a 4 or 6 bolt flange in the front where it can be removed, thus allowing you to take a broom to scrub the inside of the water heater to remove any debris and clean the inside tank, scooping out the rubbish by hand is recommended.
Deposits from water heater.
You don't. If it is a gas water heater and you have hard water, the sound you hear is the lime deposits being heated and releasing gases. The only way to fix this is to buy a new water heater and install a water softener. This is also true for electric water heaters.
MINERAL DEPOSITS ON THE BOTTOM OF THE TANK
All of the above. Mineral deposits form on all piping and water appliances.
Depends on the size of the heater Commerical etc
perhaps the water heater is clogged with lime deposits.. ? but I have no clue
It depend of what filter system you are using. If you drain your heater roughly every 6 months then you should get about 20 years out of your water heater. If your water heater lasts longer than the average life span of 20 years then it would be highly recommended that you replace it.
It's possible hard water deposits have built up inside. To prevent this and the early demise of your water heater, drain and flush the heater at least once a year.
High temp stove pipe paint recommended.
Fixing a water heater on your own can be dangerous and difficult, it's recommended to get a professional to look at it. If it's just a problem, it's probably only 50-150 dollars. If you have to replace your water heater you're looking at $750-800.
Water heaters are recommended to be set at one hundred and twenty degrees. This is to help save energy as well as prevent scalding. It also helps to remove bacteria from water.
Causes mineral deposits that inhibit heat transfer thus robbing you of fuel
Mineral deposits on the bottom of the tank and a failure is very near
Heater cores are usually well protected from mechanical damage but they can be damaged by corrosion and sediment deposits. If you change the coolant in accordance with the manufacturer's recommendations you will extend the life of the heater core, the water pump and the radiator.
form_title= Water Heater Maintenance form_header= Have your water heater looked at by a professional! How old is your water heater?*= _  How old is your home?*= _  What is your water heater model?*= _ 
form_title= Tankless Water Heater form_header= Repair or install a tankless water heater in your home! Do you need a tankless water heater repaired or installed?*= () Repaired () Installed What size water heater do you need?*= _  What is your budget on the water heater?*= _ 
form_title= Water Heater Installation form_header= Stay warm with a water heater. Are you replacing an old water heater?*= () Yes () No What is your desired capacity?*= _  Have you ever used a water heater?*= () Yes () No
It is a water heater, not a hot water heater. There would be little point in using a hot water heater. I assume that is your point.
form_title= Tankless Hot Water Heater form_header= Save money with a tankless hot water heater. Do you need to remove an old water heater?*= () Yes () No Do you want an energy efficient water heater?*= () Yes () No Where will you be installing the hot water heater?*= _ 
I am considering buying a gas water heater. How does a gas water heater work?
form_title= Water Heater Replacement form_header= Get rid of a broken water heater. What size water heater do you need?*= _  DO you want a tankless water heater?*= () Yes () No Do you want to purchase an extended warranty?*= () Yes () No
It is just a water heater. People just say hot water heater without thinking.