There is a procedure for determining pump and filter size.
We do this by determining the Total dynamic head (TDH), turnover rate, and GPH
required to turn your "X" amount of gal of water through the system . TDH is the amout of
resistance on the systems plumbing, and equipment while running the system. You
should turn your water (circulate all the water through the system) within 6-7
hrs. It should be accomplished twice a day min. per day.
The best way to determine pump and filter size is by the exact values method.
If your pool is just being built your builder will be able to get the exact
amount of resistence in the system by measuring all
the lengths, and fittings.
--------------------------------------------
There are several other ways of determining TDH also...
1)Determine gpm (gal per min.)
** "X" gallons / 7hrs(turnover rate)= X gal
per hr.
NOTE (L x W avg. depth x 7.5 = gallons)
X/ 60 min= #gpm needed under the TDH of the system to turn the water over in 7
hrs.
2) determining TDH
**Thread a vacuum guage on
the drain in front of the pump....(the small little
plug)
Note the system must run with the existing equipment to determine TDH this way
It (the vacuum guage) measures inches of mercury...every
inch of mercury equals 1.13 ft. of head
the pressure guage on your filter psi
(pounds per sq. inch)...every 1 psi= 2.31 ft. of
head.
Multiply both out and then add them together. This is
the most accurate way to determine TDH.
_________________________________________
3) A less accurate way of determining TDH...(if the system does not run) is as
follows:
1) Suction side....assume 2 ft of head for every 10 ft. the system is away from
the skimmer(s)
2)Determine how many feet from the furthest return
double that amout to allow for fittings.
3) Consult manufacture for head of specific equiupment desired
add 5 for every maindrain, return, and skimmer.
add em up for TDH
---------------------------------------
One more thing that is very impt. you do not want your
flow rate to be more than 10 ft per second. water
creates friction and can wear pump components, filter grids, valves, and heater
parts......
Some facts
50gpm in a 1.5" pipe=7.9 ft per sec
50gpm in a 2" pipe= 4.8 ft per sec
Take your pipe size into consideration.