From http://www.swimmingpoolsteve.com/pages/pools.html - Learn what can cause your swimming pool plaster to have brown stains. Pool plaster is essentially white sand and white cement which is porous and can stain easily if left unmaintained. This is especially true for new pool plaster as new pool plaster can become stained very easily. Great care must be taken to protect new pool plaster from stains. Iron can also cause brown staining and could be coming from broken or old pool equipment. When brown stains suddenly appear on pool plaster swimming pool technicians will often inspect the equipment specifically for a failing pool heater. ... https://www.youtube.com/watch?v=30frZ7XMKAM

From https://www.swimmingpoolsteve.com/pages/vs-programming.html - In this video we test the flow rates and power consumption of a 24 hour dynamic filtration schedule for a basic swimming pool (around 18.5K gallons at 3 turnovers of the total pool volume per day) that is using a Black + Decker Variable Speed 1.5hp pool pump on 2" pipes with a 150 square foot cartridge filter and approximately 30' total dynamic head. This schedule will result in approximately 56,000 gallons of filtered water for just $0.80 every day (based on the national average electricity cost of $0.13/kWh). Knowing that all pools will have their own individual flow rates and restrictions will help you understand the pools specific requirements. Flow rates can be measured using a properly installed flow meter which can help to dial in your system for maximum efficiency and savings. This same 24 hour schedule can be seen demonstrated on a 1.5" plumbing system here: https://youtu.be/w_B4jUU_5Ds #SwimmingPoolSteve #filtrationschedule #poolpumps ... https://www.youtube.com/watch?v=FnFQgfm11gg