Overflow advice needed!

smallreefdave · #1 12/28/2007, 08:01 PM

I have just set up my 180 with 1" overflows in each corner, with 4 3/4 inch returns (2 as part of over flow, 2 running over back of tank via u-tubes). The return pump is a Blueline HD100, rated at 1900 GPH at 0 feet. The overflows can't keep up (that is given),so I added a HOB overflow to supplement. There is still slow build up of water in the tank, which would cause it to eventually overflow....unless....I close a ball valve some.

I have a ball valve on each end of the return pump, in the event I ever need to shut off the water and remove the pump (along with unions to allow the removal). Blueline's website does not state if it is safe close the ball valve somewhat to reduce the flow (on the discharge end of the pump). It seems to me it would be about the same as adding head resistance to the pump. I did some research on Iwaki pumps, and their website says it is ok to do that, to a maximum flow reduction of 50% of the pumps capacity.

Does anyone have any input on this? It would be greatly appreciated.

RobsReefs · #2 12/28/2007, 08:10 PM

I would just t off the return line and put a gate valve or ball valve on one side and return what is not needed to the sump.

poppin_fresh · #3 12/28/2007, 09:32 PM

I would ditch the HOB overflow.

Without knowing the Blueline, I would agree with the above. T some of the output back to the sump.

smallreefdave · #4 12/29/2007, 02:23 AM

Great idea! I will plumb that in today, and I will get rid of the HOB, I hated that idea from the start. Had the thing for like 3 years, and this is the first time it has seen water.

Eldredge · #5 12/29/2007, 12:57 PM

Sounds like you got it figured out, but if you wanted more flow and didn't mind going over the back of the tankwith the reuturn, you could use all of the overflow pipes to feed the sump and return the water over the back (four overflow pipes). I did this and it works great, but you don't have everything contained inside the overflows.

firedogg2 · #6 12/29/2007, 01:10 PM

From what I know it is ok to reduce the flow on the output of a pump just never the input.

sjm817 · #7 12/29/2007, 02:05 PM

Use a smaller return pump or cut back the flow of what you have.

smallreefdave · #8 12/29/2007, 02:12 PM

I have plumbed in the Tee and a ball valve and it seems to work fine. If I don't feel it is giving enough overall flow, I will do exactly as Eldredge mentioned, using all of the holes in the overflow as exactly that, and do allmy returns over the back edge of the tank.

Thanks to everyone for the help on this one!!!!!

Now I have another question in regards to the flow. One corner flow works great, the other however seems to build up water to a higher level. The U in the stand pipes are at exactly the same height. Once it reaches the TOP of the left corner overflow box (way over the level where the grille on the overflow is), it drains fine, but shouldn't both overflows be going to the same height (tank is level according to my 6' level). The right side overflow water level is about 1.5 inches lower than the one on the left. Any thoughts?