Hi All,
Long time no write.
I just want to add some info to this excellent thread.
Those from countries with 50Hz ( mainly Asian and Europe ) electric supply please request proper pump curve based on 50HZ.
Most US brands like Hayward and Pentair will show 60HZ pump model and they run faster and has approx 23% more output than the 50hz cousin.
I am a victim to such misinformed data on my main pump, the Hayward.
The best solution I have done was, I install a flow meter. Its cheap, under US$150 for mechanical one.
This read all parasitic value of elbows and so on.
As an illustration to what mas985 indicated that check valve will create poorer water flow and some are worse than other.
This is using my trolley pump, a 2nd pump I use to assist main pump. I can easily remove any check valve to test.
With Check Valve. Cheapo ball type.
[attachment=1:1uxulj6g]With check valve.jpg[/attachment:1uxulj6g]
If No check valve at all. Sorry this trolley pump does not have flow meter to show real GPM. The flowmeter need PVC pipe and some straight section to install.
[attachment=0:1uxulj6g]Without check valve.jpg[/attachment:1uxulj6g]
I did use model below :
For my main stationary pump and the vacuum gauge shows improvement.
The mistake my pool builder made which I can not fix is : 2 HP Hayward pump using 1.5" PVC all the way.
I did some math years ago and I paid 20% extra energy bill or US$360 per year ( for approx 7 years now ) for the loss of the flow due to small pipe. In other words, I could get better flow for the same energy bill if 2" PVC as output pipes were used and combined with perhaps 2.5 in suction pipes.
So this thread is so useful. Too bad I join this forum after my pool was built.
Later guys.