POOL AND SPA OPERATOR HANDBOOK EXAM QUESTIONS AND ANSWERS VERIFIED 2025/2026 EDITION CERTIFIED POOL & SPA OPERATOR (CPO) CERTIFICATION

POOL AND SPA OPERATOR HANDBOOK EXAM QUESTIONS AND ANSWERS VERIFIED 2025/2026 EDITION CERTIFIED POOL & SPA OPERATOR (CPO) CERTIFICATION “whole range chlorine in a pool: ____ to _____ - CORRECT ANSWER 1, 5" "ideal range chlorine in a pool: ____ to _____ - CORRECT ANSWER 2, 4" "whole range chlorine in a spa: ____ to _____ - CORRECT ANSWER 2, 10" "ideal range chlorine in a spa: ____ to _____ - CORRECT ANSWER 3, 5" "breakpoint chlorination equation - CORRECT ANSWER BPC = 10 x CC [BPC = 10 x (TC - FC)]" "whole cyanuric acid range: _____ to ______ppm - CORRECT ANSWER 0, 100" "ideal cyanuric acid range: _____ to ______ ppm - CORRECT ANSWER 30, 50" "acts as a protection for chlorine compounds from UV light - CORRECT ANSWER cyanuric acid" "CyA will act as a stabilizer for _______ but does not stabilize ________ - CORRECT ANSWER free chlorine, bromine" "The only way to reduce CyA concentration is to _______ - CORRECT ANSWER dilute the water and replace it" "whole range of bromine: ____ to _____ - CORRECT ANSWER 2, 10" "ideal range of bromine: _____ to ______ - CORRECT ANSWER 4, 6" "second most common disinfectant in the pool - CORRECT ANSWER bromine" "two types of bromine used - CORRECT ANSWER sodium bromide, solid bromide" "Bromine in natural form is a ______ but is in _____ form when added to pools - CORRECT ANSWER reddish brown liquid, solid" "__________ is similar to hypochlorous acid - CORRECT ANSWER hypobromous acid" "whole range of calcium hardness in a spa: ____ to ____ - CORRECT ANSWER 100, 800" "ideal range of calcium hardness in a spa: ____ to ____ - CORRECT ANSWER 150, 250" "amount of calcium content in the water - CORRECT ANSWER calcium hardness" "calcium hardness is measured as ______ - CORRECT ANSWER calcium carbonate (CaCO3)" "calcium not in solution (as a solid) is called _____ - CORRECT ANSWER scale" "calcium hardness is affected by _______ - CORRECT ANSWER temperature" "when temp rises, calcium hardness becomes ______ - CORRECT ANSWER less soluble" "low calcium hardness leads to (3) - CORRECT ANSWER corrosive water, wall stains, heater failure" "if you have low calcium hardness, add - CORRECT ANSWER calcium chloride" "high calcium hardness leads to (3) - CORRECT ANSWER scale, cloudy water, clogged filters" "the only way to lower calcium hardness is to _____ - CORRECT ANSWER partially drain the water and replace it" "max temperature of a pool or spa - CORRECT ANSWER 104 degrees" "at higher temps, there is an increased tendency for _____ - CORRECT ANSWER scaling" "at lower temperatures, there is an increased tendency for ______ - CORRECT ANSWER corrosion" "maximum total disolved solids - CORRECT ANSWER 1500" "saturation index equation: SI= - CORRECT ANSWER pH + TF + CF + AF + TDSF" "green water - CORRECT ANSWER presence of copper" "red-brown water - CORRECT ANSWER presence of iron" "number one reason for cloudy water - CORRECT ANSWER improper filtration" "too much calcium in the water leads to - CORRECT ANSWER scale" "cause of foaming - CORRECT ANSWER organic waste" "three types of algae - CORRECT ANSWER green, black, yellow" "most common and most easily controlled algae - CORRECT ANSWER green" "algae resulting from poor pool circulation - CORRECT ANSWER black" "algae that is difficult to control and often requires_____ - CORRECT ANSWER yellow, algaecide" "water chemistry and increased bather load can account for _____ - CORRECT ANSWER cloudiness" "used as a water clarifier to help remove small particles from the pool - CORRECT ANSWER flocculent" "lighter, yellow color shows _____ pH - CORRECT ANSWER low" "brighter, pink color shows ______ pH - CORRECT ANSWER high" "phenol red is used to test _____ - CORRECT ANSWER pH" "always add _____ to ______ - CORRECT ANSWER chemical, water" "patrons must wait ______ minutes after adding chemicals - CORRECT ANSWER 30" "pool volume is measured in _____ - CORRECT ANSWER gallons" "flow rate is measured in ______ per ______ - CORRECT ANSWER gallons, minute" "average turnover rate for a swimming pool - CORRECT ANSWER 6 hours" "average turnover rate for a spa - CORRECT ANSWER 30 minutes" "average turnover rate for a wading pool - CORRECT ANSWER 1 - 2 hours" "flow rate = - CORRECT ANSWER pool volume / turnover rate / 60 minutes per hour" "if there is a problem with the main drain, you must _______ - CORRECT ANSWER close the pool immediately" "hair lint strainer needs to be cleaned when - CORRECT ANSWER the vacuum gauge of a high rate sand filter is elevated" "each electrical system must have ________ - CORRECT ANSWER ground fault circuit interrupters (GFIs)" "who is responsible for taking daily logs? - CORRECT ANSWER pool operator" "What does the SMART stand for - CORRECT ANSWER Specific, Measurable, Achievable, Relevant, and Time Based" "Risk management you take several key factors into consideration, what are they - CORRECT ANSWER Negligence, standard of care, duty of care, record keeping" "Negligence - CORRECT ANSWER Unintentional fault or careless resulting in injury, Negligence is the failure to act in accordance with the corresponding standard of care" "Standard of care - CORRECT ANSWER It's the care that the public expects from the operator," "Duty of care - CORRECT ANSWER The duty of care is the amount of reasonable care owed to individuals using the aquatic facility" "Ounces divided by 16 equals what - CORRECT ANSWER Pounds, so 36 ounces divided by 16 = 2.25 pounds" "Grams divided by 1000 equals kilograms - CORRECT ANSWER 2500 divided 1000 equals 2.5 kilograms" "Yards x3 equals feet - CORRECT ANSWER Yards X 3 equals feet" "Meters X 3.28 equals feet - CORRECT ANSWER Meters X 3.28 equals feet" "Fluid ounces divided by 8 equals cups - CORRECT ANSWER Fluid ounces divided by 8 equals cups Example is 32 fluid ounces divided by 4 cups" "Milliliters divided by 1000 equal liters - CORRECT ANSWER Milliners divided by 1000 equal liters Example is 950 divided 1000 equals 0.95 liters" "Fluid ounces divided by 128 equals gallons - CORRECT ANSWER Fluid ounces divided by 128 equals gallons Examples is 640 fluid ounces divided by 128 equals 5 gallons" "Milliners divided by 1000 equals liters - CORRECT ANSWER Milliners divided by 1000 equals liters Example is 19,000 divided by 1000 equals 19 liters" "Calculating liters in constant slope pool - CORRECT ANSWER Liters = Area times average depth X 1000" "How to calculate multi shaped pool - CORRECT ANSWER Divide the pool into sections to get volume" "Calculating surface area and gallons in Oblong pool - CORRECT ANSWER Area is R X R X3.14 + L times width" "Rectangle pool - CORRECT ANSWER L times Width is area then area times average depth times 7.5" "Circular - CORRECT ANSWER R times R times 3.14. Then area times the average depth times 7.5" "Oval and kidney pools area - CORRECT ANSWER Take A and B and times it by 3.14, then Gallons will equal area X average depth times 7.5" "Average depth for 1 inch of water lose - CORRECT ANSWER 1 foot divided by 12 equals 0.0833" "How to calculate Gallons for multi depth circulars spa - CORRECT ANSWER Section A is to the seats and section B is from the seat down" "Area for section is R X R X 3.14 - CORRECT ANSWER The radius is found by the equation R equals diameter divided by 2" "How many diseases are caused by germs that are easily killed by chlorine or other disinfectants - CORRECT ANSWER One fourth" "What venue had most closures - CORRECT ANSWER Child care pools" "Pool and spa codes are at the state level - CORRECT ANSWER True" "RWI stands for what - CORRECT ANSWER Recreational water illness" "Protozoa - CORRECT ANSWER Are single cell microscopic organisms, are larger than bacteria and viruses and were responsible for 66 percent of the gastroenteritis outbreaks with treated swimming pools" "Crypto - CORRECT ANSWER Is protected by an outer shell that allows it to survive harsh conditions including chlorine disinfections" "Giardia - CORRECT ANSWER Similar to crypto but not as resistant to chlorine" "Shigella - CORRECT ANSWER Is an infection that is present in the diarrheal stools of infected persons while they are sick for up to two weeks after the diarrhea ceases. Oral most common way, controlled by chlorine" "E coli - CORRECT ANSWER Is hundreds of strains of the bacterium escherichai coli." "Viruses - CORRECT ANSWER Smaller the Protozoa and bacteria, cannot grow outside a human body unlike bacteria" "Norovirus - CORRECT ANSWER Group of viruses" "Adenovirus - CORRECT ANSWER Cause respiratory illness, as well as other things such as ey infection skin irrational, etc." "What hepatitis can contaminate a pool - CORRECT ANSWER Hepatitis A, because it is transmitted throug feces" "Best way to prevent Hepatititis A - CORRECT ANSWER Get vaccinated" "Chlorine level and PH level for formed stool - CORRECT ANSWER 2 ppm and ensure the PH is 7.5 or less and a temperature of 77 degrees or higher, maintain levels for 25 minutes before opening" "Chlorine level and P'h level for diarrheal discharge - CORRECT ANSWER 20 ppm and maintain p'h of 7.5 or less and a temperature of 77, maintain levels for 12.75 hours" "What is the CT inactivation value? - CORRECT ANSWER Value is the concentration of free chlorine in ppm multiplied by time I minutes" "What can also be referred to as hot tub rash - CORRECT ANSWER Pseudomonas Æ rugosa found in warm water normally and is normally in a rash form" "Chlorine the most common disinfectant used in commercial pools is also a oxidizer - CORRECT ANSWER True" "Disinfectants that either do not act quiclkly against pathogens can only be considered a what - CORRECT ANSWER Supplement and should be used with a disinfectant" "What is free chlorine - CORRECT ANSWER Is the active available disinfectant in water. It is the HOCI plus OCI" "What is the common practice to maintain free chlorine - CORRECT ANSWER 2 to 4 ppm and minimum in us is 1 part per million" "What is combined chlorine - CORRECT ANSWER When free chlorine reacts with two types of contaminants in the water , ammonia and nitrogen compounds" "Available chlorine content is a comparison of the relative amount of chlorine released into water for different chlorine disinfectants. - CORRECT ANSWER Active chlorine percentage is the percentage by weight of the technical grade active ingredient in the product." "Most common chlorine in commercial pools - CORRECT ANSWER Sodium hypochlorite" "What chlorine is in tablets or granular tablets - CORRECT ANSWER Calcium Hypochlorite" "HOCI is what - CORRECT ANSWER Hypochlorous Acid or also referred to as chlorine" "Any form of chlorine plus what're equals what - CORRECT ANSWER Hypochlorous acid" "What is Hypochloroud acid - CORRECT ANSWER It is the active killing form of chlorine" "Free chlorine - CORRECT ANSWER Is the active available disinfectant in the water" "Free chlorine equals what - CORRECT ANSWER HOCI plus OCI(Hypoclorite ion)" "What is Combined Chlorine - CORRECT ANSWER It is a form of free chlorine threat reacts with two types of contaminants in the water. It when it reacts with ammonia and inorganic chloramines which do not contain carbon" "What is OCI - CORRECT ANSWER Hypochlorite ION" "What is NH2CI - CORRECT ANSWER Combined Chlorine" "What is FC - CORRECT ANSWER Free chlroine" "What is HOCI - CORRECT ANSWER Hypochlorous acid" "What is H+ - CORRECT ANSWER Hydrogen ION" "What is XCI - CORRECT ANSWER Any form of chlorine" "What is XCI plus H2O - CORRECT ANSWER HOCI" "What is NH3 - CORRECT ANSWER Ammonia" "Is combined chlorine a effective disinfectant - CORRECT ANSWER No, that's why it is important to know how much combined chlorine you have in the pool" "Sodium Hypochlorite - CORRECT ANSWER Liquid chlorine releasing disinfectant that the most common disinfectant used to treat commercial pools. Active strength is 10 to 12 percent ACC is 10 to 12 percent Ph is 9 to" "PH - CORRECT ANSWER PH is the acid level in pools" "What do unstabilized disinfectant not have - CORRECT ANSWER Carbon atom" "Calcium Hypochlorite - CORRECT ANSWER Strength is 65 to 78 percent ACC is 65 percent to 78 percent PH is 8.5 to 11" "What is Clacium Hypochlorite CA{OCI}2 - CORRECT ANSWER Is a dry form of chlorine often called Cal hypo, available in granular, or tablets. Normal ACC is 65 to 78 percent" "Lithium Hypochlorite - CORRECT ANSWER LIthium Hypochloriet is a dry, grnaualar compound of chlorine." "Chlorine Gas (CI2) - CORRECT ANSWER 100 percent strength with ph of 0" "Equation when chlorine gas enters water is as follows - CORRECT ANSWER CI plus H20 equals HOCI + HCI" "Cyanuric Acid also called stabilizer - CORRECT ANSWER The free chlorine provided by unstabilized chlorine compounds can be protected from the effects of UV lights in sunlight by addition of cyanuric acid, in short if stabilize the free chlorine to last longer in the pool" "Stabilized disinfectants - CORRECT ANSWER In is a disinfectant that has cyanuric acid built into the molucul structure, the two types are trichlor and dichlor" "Bromine HOBr - CORRECT ANSWER Bromine belongs to the same chemical family as chlorine, it is a disinfectant and is an oxidizer. It is not as strong as chlorine which make it a good choice for spas" "Two types of chlorine generated systems - CORRECT ANSWER In line generation and brine mehthod" "In line - CORRECT ANSWER Salt is added to the pool water then it passes thought the circulation device that contain electrochemical cells. These cells convert the sodium chloride into free chlorine." "Brine method - CORRECT ANSWER Has a tank containing salt and water the salt water is then converted to free chlorine with an electrochemical cell." "Ozone - CORRECT ANSWER O3" "What factors contribute to the balance of water - CORRECT ANSWER PH, total alkalinity, calcium hardness, temperature, and total dissolved solids" "PH Level - CORRECT ANSWER PH stands for potent hydrogen, which is Latin for the power of hydrogen. PH. Has the most impact on properly balanced water and user comfort. PH is the a measurement of the hydrogen T ion in concentration in water" "What is neutral when it comes to PH level - CORRECT ANSWER 6 to 8" "If less than 6 PH level what do you add, which means increasingly acidic - CORRECT ANSWER Add soda as or caustic soda" "If higher than 8 ph which is called increasingly basic you do what - CORRECT ANSWER Add muratic acid or sodium bisulfate" "What is the PH of human tears - CORRECT ANSWER 7.5" "What is the recommended ph of pool/spa water is slightly alkaline. What is this - CORRECT ANSWER 7.2 to 7.4" "The acceptable range for ph is what - CORRECT ANSWER 7.2 to 7.8" "Should you fix the ph or alkalinity first - CORRECT ANSWER Fix alkalinity first then ph level, normally ph will correct spelt after alkalinity is fixed" "Most common chemical used to lower ph in pools - CORRECT ANSWER Muratic acid" "What is Alkalinity - CORRECT ANSWER It is the the measure of the ability of water to resist changes in PH levels, it's like a anchor to keep pool water were it needs to ne" "What makes up alkalinity - CORRECT ANSWER Bicarbonate, carbonate, and hydroxide ions" "What is ideal level for alkalinity - CORRECT ANSWER 80 to 120 parts per million" "4 types of solid chlorine - CORRECT ANSWER calcium hypochlorite, lithium hypochlorite, trichlor, dichlor" "liquid chlorine - CORRECT ANSWER sodium hypochlorite (NaOCl)" "how active is gas chlorine - CORRECT ANSWER 100%" "the active killing form of chlorine in water - CORRECT ANSWER hypochlorous acid (HOCl)" "HOCl = ______ - CORRECT ANSWER H+ (hydrogen ion) + OCl- (hypochlorite ion)" "most common granular chlorine (pH range) - CORRECT ANSWER calcium hypochlorite (8.5 - 11, used to super chlorinate water)" "not common form of chlorine due to low active strength (pH) - CORRECT ANSWER lithium hypochlorite (10.8)" "tablet/stick chlorine usually used in erosion feeder (pH - what will it do?) - CORRECT ANSWER trichlor (2.8 - 3.5, lower alkalinity and pH over time)" "salt used as a disinfectant (pH) - CORRECT ANSWER dichlor (6.7 - common in vinyl lined pools)" "most common type of chlorine used (pH) - CORRECT ANSWER sodium hypochlorite (NaOCl - 13)" "______ needs special training to use and has a pH of ____ and will _____ when added to water - CORRECT ANSWER gas chlorine, 0, lower pH" "chlorine is most effective as a pH of _____ - CORRECT ANSWER 7.5" "active disinfectant in the water - CORRECT ANSWER free chlorine (FC)" "FC is determined by the ______ test and is maintained between ____ and ____ ppm - CORRECT ANSWER DPD, 2, 4" "equal to the amount of hypochlorous acid (HOCl) and the amt of hypochlorite ions (OCl-) - CORRECT ANSWER free chlorine (fc)" "the result of free chlorine reacting with organic compounds - CORRECT ANSWER combine chlorine (CC)" "common name and max for pools and spas for combine chlorine - CORRECT ANSWER chloramines, 0.2, 0.5" "CC = - CORRECT ANSWER TC - FC" "what will a DPD measure - CORRECT ANSWER TC, FC" "how much CC should a pool have ideally - CORRECT ANSWER zero" "shocking the pool is also called - CORRECT ANSWER breakpoint chlorination" "breakpoint chlorination is the conversion of ________ into ______ - CORRECT ANSWER combine chlorine, nitrogen gas" "bromine releases _____ and _____ when added to water - CORRECT ANSWER hypobromite ion, hydrogen ion" "bromine will ______ pH when added to water - CORRECT ANSWER lower" "whole range of pH: ____to_____ - CORRECT ANSWER 7.2, 7.8" "ideal range of pH: ____ to ____ - CORRECT ANSWER 7.4, 7.6" "things that influence pH (6) - CORRECT ANSWER swimmer waste, disinfectants, water source, air borne debris, chemical balance, evaporation" "low pH leads to (3) - CORRECT ANSWER corrosive water, surface staining, surface etching" "if you have low pH, you must add - CORRECT ANSWER soda ash (caustic soda - sodium carbonate)" "high pH leads to (5) - CORRECT ANSWER scaling water, cloudy water, clogged filters, reduced circulation, eye/skin irritation" "if you have high pH, you must add ____ or _____ - CORRECT ANSWER muriatic acid, sodium bisulfate" "whole range of total alkalinity: ____ to _____ - CORRECT ANSWER 60, 180" "ideal range(s) of total alkalinity: ____ to _____ - CORRECT ANSWER 80, 120" "the measure of the ability of the water to resist change in pH - CORRECT ANSWER total alkalinity" "acts as a pH buffer - CORRECT ANSWER total alkalinity" "_____ will affect total alkalinity - CORRECT ANSWER cyanuric acid" "if your pH is high, you will require a ______ total alkalinity - CORRECT ANSWER lower" "if your pH is low, it is acceptable to have a ______ total alkalinity - CORRECT ANSWER higher" "low total alkalinity leads to (4) - CORRECT ANSWER pH bounce, heater failure, surface etching, green water" "if you have low total alkalinity, add ______ - CORRECT ANSWER sodium bicarbonate" "how much sodium bicarbonate should be added to increase total alkalinity? - CORRECT ANSWER 1.4 pounds per 10000 gal of water" "high total alkalinity leads to (4) - CORRECT ANSWER pH lock, cloudy waters, clogged filters, reduced circulation" "if you have high total alkalinity, add _____ or ______ - CORRECT ANSWER muriatic acid, sodium bisulfate" "whole range for calcium hardness in a pool: ____ to ____ - CORRECT ANSWER 150, 1000" "ideal range of calcium hardness in a pool: ____ to ____ - CORRECT ANSWER 200, 400" "pool capacity (in gallons) is equal to the pool _______ times _______ - CORRECT ANSWER volume, 7.5 gallons" "minerals that cause stains (3) - CORRECT ANSWER iron, copper, manganese" "chemicals used to neutralize chlorine (2) - CORRECT ANSWER sodium thiosulfate, sodium sulfite" "acceptable range of free chlorine in a pool: ____ to ____ppm - CORRECT ANSWER 1, 3" "ideal chlorine in a spa - CORRECT ANSWER 4" "what causes the chlorine smell in an indoor pool - CORRECT ANSWER chloramines evaporating" "what are caused by chlorine combining itself to organic maters (like ammonia)? - CORRECT ANSWER chloramines" "which chlorine has a pH of nine and raises the pH of water? - CORRECT ANSWER liquid chlorine" "_____ deteriorates quickly into exposed air - CORRECT ANSWER sodium hypochlorite" "When using CA to stabilize a pool the chlorine level must stay above _____ ppm - CORRECT ANSWER 2" "how is bromine different from chlorine? - CORRECT ANSWER combine bromine can be used as an effective sanitizer" "Breakpoint chlorination is an effective technique to reduce ________ which cause _______ - CORRECT ANSWER inorganic chloramines, chlorine odor" "what can be performed after a pool has been drained to remove stains? - CORRECT ANSWER acid wash" "what does a sequestration agent (chelating) do? - CORRECT ANSWER form chemical bonds to metals dissolving them in the water" "pump cavitations may be caused by (4) - CORRECT ANSWER debris in skimmer, debris in hair lint strainer, partially closed/restricted suction lines, dirty vacuum filter" "the more particles and dirt that a filter removes, the slower the _____ - CORRECT ANSWER flow rate" "removes the smallest particle size of any pool spa filtration device - CORRECT ANSWER diatomaceous Earth filter (DE)" "what occurs over time in a sand filter - CORRECT ANSWER channeling" "channeling in a filter causes - CORRECT ANSWER a bypass in the filtration process, causing unfiltered water back into the pool" "when the water in the pipe is ______ then backwash is complete - CORRECT ANSWER clear" "As dirt and debris collect in a sand filter the ______ pressure increases and the _______ pressure decreases - CORRECT ANSWER influent, effluent" "are cartridge filters backwashed? - CORRECT ANSWER no (removed and hosed off)" "are sand filters backwashed? - CORRECT ANSWER yes" "depth markers should be at - CORRECT ANSWER horisontal surfaces, vertical surfaces, and twenty feet apart" Public pools are classified in the following manner - CORRECT ANSWER Class A pools, Class B Pools, Class C Pools, Class D Pools, Class E Pools, Class F pools" "Class A Pools - CORRECT ANSWER Competitive pools, but is not limited to competitive events" "Class B pools - CORRECT ANSWER Pool intended for public recreational use, refereed to as a public pool" "Class C Pools - CORRECT ANSWER For use by apartments, condominiums, property owners associations, etc. also referred to as a Semi Public Pool" "Class D Pools - CORRECT ANSWER Special operated pools, examples are wave pools, surf, action, activity, leisure rivers, ect. Referred to in code books as other pool or Aquatic Recreational Facilities" "Class E Pools - CORRECT ANSWER Any pool used for physical therapy and operated above 86 degree Fahrenheit. This type of pool is sometimes referred to as a therapy pool" "Class F pools - CORRECT ANSWER Kiddie pools or Wading pools" "Four Management work functions - CORRECT ANSWER Planning, Organizing, Leading, Controlling" "Planning - CORRECT ANSWER Deciding the course of action before the work is started" "Organizing - CORRECT ANSWER Defining and connection the work to be done so it can be excuted" "Leading - CORRECT ANSWER encouraging people to take proper action" "Controlling - CORRECT ANSWER Measuring and regulating all work in progress and evaluation the results." "What is the pool volume deviation from the actual volume when trying to obtain the volume of the pool - CORRECT ANSWER Plus or minus 5 percent" "Surface area equals length times width - CORRECT ANSWER The surface area of any aquatic facility is that area o ft he pool water exposed to the air." "For every cubic foot of water there are 7.5 gallons of water - CORRECT ANSWER For every cubic meter of water there are 1000 liters of water" "How do you calculate volume - CORRECT ANSWER To. Calculate pool volume in gallons, multiply the surface area by the average depth and a conversion factor of 7.5. This factor requires the length, width, and depth to be measured in feet." "Calculating gallons in constant slope pool - CORRECT ANSWER Gallons equals area times average depth times 7.5" "Average depth equals shallow en plus deep end divided by 2 - CORRECT ANSWER So if 3.5 feet plus 8.5 divided by 2 equals 6 feet"