Does a hot tub have a filter that runs like in a pool? If so, how often should it come on?
Answers:
They do have filters. Generally cartridge filters. Most are located in the skimmer. There are lots of exceptions, though. Some are under the skirt. Run the spa at least 4 hours a day to filter the water, and keep it hot.
Other answers:
A hot tub does have a filter. But it's always working. When the water is circulating (ie the jets are on) it gets sucked through a rough filter (usually located at the bottom of the tub. It goes through the filter and comes back into the tub via the jets. That's also how the water gets heated. Therefore, whenever you circulate the water, the filter is working. It does need to be changed every so often, though.
A hot tub does have a filter. But it's always working. When the water is circulating (ie the jets are on) it gets sucked through a rough filter (usually located at the bottom of the tub. It goes through the filter and comes back into the tub via the jets. That's also how the water gets heated. Therefore, whenever you circulate the water, the filter is working. It does need to be changed every so often, though.