Water pumps and filters

Question

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The text above is a follow-up to ...Thank you for your informative and prompt response.  I hope you don't mind if I gleam more info from you. What size pump and which mfg would you recommend would be sufficient for this pond.
Also I have a Triton II Sand filter--this is another poor selection I've made since sand is too fine.  Could the filter media be converted to a bead filter or another media
without harm to the system or should I also "throw this out"
and invest in another kind.  If so, what?

-----Question-----
Pond Size approx 5200 gallons water.  5ft height waterfall.
Pond spreads half-circle around waterfall and joins a small
pond area (19ft x 12 ft x 1 ft deep).  Operating with 2 Pentair whisperflo pumps 1/2 HP fall, 3/4 HP circulation (115-208 Volts 6-11.5Amp). Is it 115 V 11.5 on amp? 3450 rpm
Elect bill $300+ ea month.  Some says pump too excessive.
Could use a 1/8 & 1/3 HP 1750 rpm pump? I have drawn layout of pond with measurements of pipe lengths and size.
-----Answer-----
Hi,
I would also say your pumps are to big, seeing that the pond is only 1 foot deep you have plenty of surface area with the size of your pond, so apart from the volume of water being moved  which may be for the effect then the pumps are to large.
BUT it is only personal preference.
George

Answer
Hi,
I have never used a sand filter or bead filter so I am sorry that I cannot help with this also I live in the UK so have no idea of the pumps available in the USA,
you can visit my website and click on the links to koi and pond page and find links that will help you, my website is http://koi-z-are-us.20m.com you will also be able to view my Japanese garden and pond.
George.