Shall i change my ball valve?

I stand by by what I said, never restrict and over flow, ever period. I have seen the Herbie style overflows which to me are overly complicated for something that should be simple, remember the KISS principle?

You want an unrestricted flow so noting like snails, food, algae etc can lodge in the restriction and cause a flood. The smoother and mor laminar the flow the better. This not only flows more water but it will be quieter too since wate rdoes not have eddies or back currents or air pockets. I prefer reinforced vinyl tubing over PVC for this reason. If you use PVC it should have long radius sweeps or 45's instead of 90 degree elbows.

A simple standpipe design like the Durso or I prefer the Stockman works very well for injecting just enough air to really make the flow good and almost silent. I recently bought a couple Maggie Mufflers for my 1" standpipe and was very disappointed, they are much louder than my modified Stockman design and the level goes up in the display so I know the yare not flowing as well. I ended up drilling out the air hole in one of the Maggies and inserting a piece of airline tubing down into the standpipe and it helped by the Stockman is still quieter and flows more. I see no reason to complicate a siphon which is all an over flow is, if you need to throttle do it with the pump, not the siphon.

 

I've just purchased the pump so i don't really want to change it , how would i adjust my overflow box to allow the correct amount of water to flow without the need of a valve?

I'm going to look into the stockman overflow , thanks for the info

 

If it is a hang on back style overflow the inside tank portion of the overflow box should have an adjsuatble height, usually a couple nylon screws you loosen and adjust up or down.
If it is a built in overflow it should be factory set for the optimal height when using the correct return flow rate. My internal overflow has teeth cut about 3/4" long across the top of the box. When I am running say 400 GPH the water level barely comes up the teeth maybe 1/4" and the tank surface level appears low. When viewed from the front I can see a noticable distance between the plastic tank trim and the water level. When I increase the flow to 600 the level rises and its not as noticable but when I increase the flow to around 850 to 1000 GPH the water is close to the tops of the overflow teeth and there is no noticable gap between the trim and water level. As I said before, the return flow rate determines the surface level, along with the adjustable hang on back overflow box if you have that style overflow. Restricting the overflow to set water level is a recipe for disaster and will lead to floods or burnt up return pumps or both.

What size is your overflow and what GPH is it rated for? What size piping or tubing are you using and how is it plumbed? Does the overflow have a standpipe and how is it configured? Do you have an air intake on the overflow? How big is your sump, your return pump chamber and what wate rlevel do you keep it at? What brand and model pump do you have and what does the pump curve show it delivers at 4 or 5 feet of head? My overflow is internal and 1" with zero restrictions and enters the sump with a long radius sweep so no blockages. The return pump has been an OceanRunner 3500 (900 GPH at 0' and around 650-700 at 4' head) for 9 years but was changed to a WaterBlaster HY5000 about two months ago and the flow is around 900 GPH now. I think they are very conservative with their ratings as it almost exceeds my 1" overflows capacity. I do still have a ball valve on the retrun pump discharge if I feel the flow it too much but the overflow remains unrestricted at all times.