1 inch overflow ?

I'm seeting up my 90G it came pre drilled with 1inch drain and a 3/4 supply . I bought a Iwiki MD-40rt 1/12hp 822 gph at 21 foot I found a headloss calkulator . With the valves a 90's I should have been in the 650gph area . So the tank would not overflow I had to buy a Valve and put on the discharge of the pump and close it half way . How many GPH should return to the sump through a gravity 1" drain ? It dosen't matter if I use the durso contraption to quite it down or just the open pipe and it dosen't seem to be restrickted in the pluming the pipe is never full ? Thanks for any help

 

Lots of variables come into play but after 45 yrs as a licensed journeyman and master plumber and as many yrs setting up tanks or more on average a 1" will do about 900 gph ..With the head you are dealing with and length of average run and fittings for an under the tank sump set up.. Now if you want to get into the water temps and specific gravity and amount of fittings and degrees of the turns and length of horizontal and vertical runs and valves we can dig deeper . But that pump on average will not over run that drain system if hard piped . Use a ridged hose that will decrease flow rates on the drain ..

 

Tangster thanks for the reply I didn't think the pump should overflow the tank . The sump is in the basement I'm using a 100G rubbermaid stock tank and the return from the tank is hard piped from the water line in the tank it's about a 6 foot drop to the sump .

 

LOL no it will never over the drain then I have 2 1" and pushing close to 2,000 GPH from a Dolphin SAS 9700 to the system and my sump is in the basement and over 30' I did put the 1" lines into a 1.5 " line down to basement then went Horizontal with 2" over to sump