Can't get the full siphon started on my shadow overflow, please help...

[Kilroy]

Hey Everyone,

After many long nights of trying to get my first tank up and running, I am at the last roadblock (I hope) before I can patiently wait for the cycle to begin. I held off on a build thread because I was hoping to do one once the cycle started but here I am. I cannot for the life of me, figure out how to get a full siphon on my Bean Animal overflow. As far as I can tell it’s because I don’t have enough water in the DT? I have added as much as I can without having to crank the return pump up to 100%. It seems like the airhole at the top of the full siphon should be covered with water but I just can’t achieve the right level. When I adjust the gate valve, I can close it completely and it still won’t cover it. It is super noisy and of course annoying that the job is not done.
You can see that the sump is at this point not even using the bubble trap since the water level is so high. Also, isn’t it odd that I need to have the pump past 68% to even get water flowing into the tank? I am wondering if I am missing something? I have 1.5” reduced to two .5” returns. Could it be the check valves?
As for the drains, my primary is in the middle, emergency on the right. It flows into the basement where I have the first container where it has the clarisea, then it drains into the skimmer portion of the sump tank, followed by a bubble trap and then return chamber. The return also feeds the refugium, approx. 38g.
I hope some of you can shed some light on what I am doing wrong. I have pics of my tank, basement sump and overflow box.

I can honestly say this hobby has already begun teaching me patience!


120g SC Aquariums Peninsula
16” shadow overflow
Giesemann Aurora 48”
Reef Octopus Elite 200 SSS
Clarisea sk5000 roller mat
Abyzz a400
Mp40
Carbisea life rock

below is the overflow box and you can hear the sound if you turn up the volume.

 

[ScottB]

There are some folks around here that are pretty good with this stuff, so we will keep bumping the post until one chimes in.

My first thought is not enough water returning to the display. What was your calculation of head pressure to get the water up from the basement through 2 X .5" inch lines? Here is a calculator: https://pentairaes.com/pump-calculator
Don't forget to include some pressure for the check valves or any T's. Also, don't forget to convert GPH to GPMinute for the calculator.

And these are the specs on that pump, correct?
Max Flow - 6,060 GPH
Max Head - 30.55 feet

That is some pretty good pushing power for sure, but I don't know your head pressure. So calc that first.

 

[Kilroy]

Thanks for the calculator and for your reply. I am unsure how to put in the values though, since I have a 1.5" return for 9.5' then it T's off into two .5" flex hose. Not sure what value to put in the nominal pipe diameter? Do I average the values or add calculate both sections separately and add them together?

 

[Kilroy]

There are some folks around here that are pretty good with this stuff, so we will keep bumping the post until one chimes in.

My first thought is not enough water returning to the display. What was your calculation of head pressure to get the water up from the basement through 2 X .5" inch lines? Here is a calculator: https://pentairaes.com/pump-calculator
Don't forget to include some pressure for the check valves or any T's. Also, don't forget to convert GPH to GPMinute for the calculator.

And these are the specs on that pump, correct?
Max Flow - 6,060 GPH
Max Head - 30.55 feet

That is some pretty good pushing power for sure, but I don't know your head pressure. So calc that first.

Those are the specs yes. Forgot to include that in my reply!

 

[ScottB]

Thanks for the calculator and for your reply. I am unsure how to put in the values though, since I have a 1.5" return for 9.5' then it T's off into two .5" flex hose. Not sure what value to put in the nominal pipe diameter? Do I average the values or add calculate both sections separately and add them together?

I will gladly accept a correction from others here, but I would:
a) calc the 1.5" section
b) calc the 1/2 section and multiply by 2 as there are two lines being pushed. (and don't forget the 90 degree at the return nozzle)
c) then add a + b

 

[justingraham]

If you can completely close the full syphon gate valve and the water in the box isn’t going over the full syphon hole that means Your secondary pipe is to low it needs to be above the primary pipe

 

[justingraham]

It has nothing to do with your pump

 

[Kilroy]

I will gladly accept a correction from others here, but I would:
a) calc the 1.5" section
b) calc the 1/2 section and multiply by 2 as there are two lines being pushed. (and don't forget the 90 degree at the return nozzle)
c) then add a + b

Jeez, that puts me at 1337.6 pump head required :/

 

[lpsouth1978]

My understanding was that on a bean animal there should NOT be an air hole on the main siphon line, only on the secondary drain. The secondary should be at least a couple inches higher than than the main, but is set as high as you want the water in the overflow box. Try covering that hole and see if things improve.

 

[Kilroy]

If you can completely close the full syphon gate valve and the water in the box isn’t going over the full syphon hole that means Your secondary pipe is to low it needs to be above the primary pipe

Seeing as how I don't have a replacement U bend. Could I pop in a 1" pvc standpipe temporarily and see? or would that not work since it needs the air hole?

 

[Kilroy]

My understanding was that on a bean animal there should NOT be an air hole on the main siphon line, only on the secondary drain. The secondary should be at least a couple inches higher than than the main, but is set as high as you want the water in the overflow box. Try covering that hole and see if things improve.

So when I stick my finger over the hole the water level in the box drops until air starts sucking into the U bend of the primary.. That's why I was thinking maybe I needed more water, but I am definitely at the max amount my sump can hold. I don't want to cut down my fuge baffle to make room, but I will if it comes down to it I guess.

 

[lpsouth1978]

Seeing as how I don't have a replacement U bend. Could I pop in a 1" pvc standpipe temporarily and see? or would that not work since it needs the air hole?

that should work temporarily to test it, but you will want to extend the U bend in the long term.

 

[lpsouth1978]

So when I stick my finger over the hole the water level in the box drops until air starts sucking into the U bend of the primary.. That's why I was thinking maybe I needed more water, but I am definitely at the max amount my sump can hold. I don't want to cut down my fuge baffle to make room, but I will if it comes down to it I guess.

You want it so suck all of that water out, sort of. That is the point of that siphon line. You need to cover the hole and adjust the gate valve closed until the water going in matches the siphon capacity. as you close the valve you will limit the amount of water that can be siphoned, and the water level in the overflow will begin to rise. This may be easier if you start with the valve closed ALL the way (hole covered) and start opening it until the water level is where you want it. I would start with 1/4 turns and then make TINY adjustments once you get close. You may be surprised by how little you actually need to open the gate valve.

 

[JoshH]

As @justingraham mentioned it looks as if you're siphon and secondary lines are the same height. This needs to be changed first and a quick way to do that is just pull the elbows out of the primary and leave it an open bulkhead. Then start adjusting from there. Also, looking at your setup, Calculating your total head height is only one part of the equation. You need to factor in friction loss as well as total head height which gives you your TDH (Total Dynamic Height). With a long run and choking down your return to 2 1/2" lines, I'm not entirely surprised it takes 68% power just to get water up to the display. The calculator @ScottB Linked is a decent one but I'll dig around for one a little more comprehensive I stumbled upon a little while ago

Found it! http://www.freecalc.com/fricfram.htm

Add this calculation to your actual head height and it will give you your TDH.

 

[Kilroy]

@lpsouth1978 That did it! I took out the U bend and slapped on a spare 1.5" coupling and raised closed the valve until it hit the edge of the pipe and it is dead silent! Thanks to all for the assist! Its odd that u bends and internal piping the shadow overflow came with would not have the drains farther apart in height. Now I just have to figure out the head loss issue.

 

[Kilroy]

As @justingraham mentioned it looks as if you're siphon and secondary lines are the same height. This needs to be changed first and a quick way to do that is just pull the elbows out of the primary and leave it an open bulkhead. Then start adjusting from there. Also, looking at your setup, Calculating your total head height is only one part of the equation. You need to factor in friction loss as well as total head height which gives you your TDH (Total Dynamic Height). With a long run and choking down your return to 2 1/2" lines, I'm not entirely surprised it takes 68% power just to get water up to the display. The calculator @ScottB Linked is a decent one but I'll dig around for one a little more comprehensive I stumbled upon a little while ago

Found it! http://www.freecalc.com/fricfram.htm

Add this calculation to your actual head height and it will give you your TDH.

Ok, I hope you can find it. I am bummed that I had to bring it to .5" return bulkheads. Not sure if there is anyway I could have done it differently. Maybe made my sump a little higher? Or split it to .5" right at the last minute as it approaches the tank?

 

[JoshH]

My understanding was that on a bean animal there should NOT be an air hole on the main siphon line, only on the secondary drain. The secondary should be at least a couple inches higher than than the main, but is set as high as you want the water in the overflow box. Try covering that hole and see if things improve.

I'll add that you CAN have an air hole in the top of the primary drain elbows BUT, if you do, the top of the primary elbows have to be lower than the Crest point in the secondary drain or a full siphon will never happen unless your flow exceeds the secondary as well to a point where the hole is covered. This would require an unusually tall overflow box to accomplish.

 

[JoshH]

Ok, I hope you can find it. I am bummed that I had to bring it to .5" return bulkheads. Not sure if there is anyway I could have done it differently. Maybe made my sump a little higher? Or split it to .5" right at the last minute as it approaches the tank?

If you absolutely HAVE to go with the 1/2" returns, the solution to get the best flow possible would be to split them as close to the actual return outlets as you can. Either way you are looking at a serious choke point but bringing it as close to the outlets as possible you will reduce the effect. If it was me I would cap the 1/2" returns and go over the top of the tank with 1" on either side. Or use a reducing T at each return outlet, and go from 1" to the 1/2" regular returns then run the other outlet of the T across the length of the tank to the other side and have return outlets at the far end of the peninsula as well. This would all be hidden in the canopy and will provide you with extra flow from the far end.

 

[Kilroy]

Should I take out these check valves and just use an 1.5" one in the basement? Or just drill a hole in the lock-line? I would imagine this is not helping my head pressure issue... I am still messing with that calculator you sent me @JoshH

 

[JoshH]

Should I take out these check valves and just use an 1.5" one in the basement? Or just drill a hole in the lock-line? I would imagine this is not helping my head pressure issue... I am still messing with that calculator you sent me @JoshH

Personally... I don't use Check valves and go with a modified version of the hole in the loc-line approach. I honestly don't know how much they are limiting your flow (probably negligible compared to the drop in pipe size). I would think that the closer a check valve is to the pump the better as it will hold back more water than if it were up by the tank. It would also make maintenance easier to do in the basement vs behind the tank itself.