Straight answers about pools, hot tubs and keeping them running
Pools Shop Editorial Team 
Hot tub water usually goes foamy because of a buildup of organic material — body oils, lotions, deodorant, sweat and detergent residue — that lowers the water’s surface tension. Once that residue accumulates faster than the filter and sanitizer can handle it, the agitation from the jets whips it into visible foam. What actually causes … Read more
Both bromine and chlorine kill bacteria and other organisms in hot tub water, but they behave differently at high heat and in enclosed spas. Chlorine acts faster and costs less; bromine is more stable in heat, has a milder smell, and is gentler on skin for many bathers. Neither is inherently “safer” — the right … Read more
A hot tub’s running cost comes mostly from heating and pumping water, with chemicals, filters and water changes adding a smaller but steady amount on top. The single biggest factor is how much the heater runs, which depends on climate, insulation, cover use and how often the tub gets used. What are the main things … Read more
Biofilm is a thin, slimy layer of bacteria, fungi and other microorganisms that builds up inside a hot tub’s pipes, jets and pump housing. It forms on wet surfaces that stay damp between uses, and it matters because it can shelter organisms from sanitizer, contribute to cloudy or smelly water, and flake off into the … Read more
Hot tubs need more frequent water changes because they hold a small volume of water that gets used hard: it runs hot, it’s shared by several bodies at once relative to its size, and it’s often covered between uses. Heat speeds up chemical breakdown, and a small volume dilutes contaminants far less than a full-size … Read more
Hot tub water chemistry follows the same core principles as pool chemistry — sanitizer, pH, alkalinity — but everything happens faster and with less margin for error. A much smaller volume of water, higher temperature, heavier bather load per gallon, and constant agitation mean readings shift quickly and need checking far more often than a … Read more
Most pool pumps run well for roughly a decade before the motor wears out, though heavy use, poor maintenance or a harsh climate can shorten that considerably. Filters usually last longer structurally, but their internal media — cartridges, sand or grids — need replacing on a separate, shorter cycle. How long does a pool pump … Read more
A pool pump loses prime when air gets into the suction side of the system instead of water, so the impeller spins in air rather than moving water through the pipes. The usual causes are a low water level, a clogged skimmer or pump basket, a loose lid or O-ring, or a suction-side leak drawing … Read more
A filter pressure gauge measures how much resistance the water is meeting as it pushes through the filter media. A rising number means the filter is catching debris and getting harder to push water through. A low or zero reading usually means low flow, a closed valve, or a pump problem, not a clean filter. … Read more
Pool heaters take so long because they’re raising the temperature of thousands of gallons of water while that same water is constantly losing heat to the air, the ground and evaporation. A heater adds warmth gradually; the pool loses it just as steadily, so the net gain each hour is small. How much water is … Read more
About what you read here. Everything on Pools Shop is general information and our own editorial opinion. We research carefully and we say when the evidence is unclear, but we can be wrong, things change, and no article can know your particular situation. Please do your own research and make your own judgement rather than treating anything here as the final word. Prices, products and specifications around pools, hot tubs and their upkeep change constantly, and what suits one person will not suit another. Check current details yourself, and where a decision involves real money, safety or something you cannot undo, it is worth confirming with a qualified pool or electrical professional before you act.