Need Plumbing Diagnosis Please

[gnashty]

Well, I am trying to diagnose a plumbing issue with my durso's and drain line

I have 2 returns and 2 drains - both drains are identical in almost everyway, down to the turns and length of pipe used. they are 3/4" drains for reference.

The left side surges every so often, say every 30 seconds and may go away for several hours and come back, there is no normal rythym to it at all. I drilled a slightly larger hole in the top of the durso on 2 seperate occasions several weeks apart. It seemed to fix it but i just heard it surge again...what gives?

 

[haninja]

Mine did that until I reduced the flow. How much flow are you running on your return?

 

[gnashty]

haninja;566125 wrote: Mine did that until I reduced the flow. How much flow are you running on your return?

Sorry, I left that part out - I am using a Mag 18 return pump and have the UV plumbed in to the left side return. I am not sure what my overflows are rated at (where do i get that info?). Its dialed back about 15% right now.

I would have thought it would have done it on both sides it is is a flow issue?

 

[haninja]

Regular overflows are rated at about 600gph each. I noticed in my tank that the surge can be affected also by the location of power heads inside the tank casing one overflow to surge and the other not.

 

[rbredding]

your under tank and durso pipes probably need to be larger.

my system has 1"pvc piping for each overflow(under the tank) and 1-1/4" dursos (check out the link in my sig to see why I enlarged the dursos.. )

remember, using pipe diameter to calculate flow is vastly different when you're using gravity to drain the pipe compared to use of a pump to pressurize the flow..



your surge is happening because the pipe is backing up (essentially)

 

[gnashty]

haninja;566130 wrote: Regular overflows are rated at about 600gph each. I noticed in my tank that the surge can be affected also by the location of power heads inside the tank casing one overflow to surge and the other not.

Funny you mention that - I have a MP40w ES on the left side of the tank running in Nutrient Export mode - this could explain why there is no rythym to the surges

Rbredding;566131 wrote: your under tank and durso pipes probably need to be larger.

my system has 1"pvc piping for each overflow(under the tank) and 1-1/4" dursos (check out the link in my sig to see why I enlarged the dursos.. )

remember, using pipe diameter to calculate flow is vastly different when you're using gravity to drain the pipe compared to use of a pump to pressurize the flow..

I would think that both would be surging if that were the issue? I dont disagree with you at all about the benefits of larger durso and Ill check out your thread

 

[rbredding]

water follows the path of least resistance.. more than likely, the dursos are different (ever so slightly) in a way that is not obvious..