Sump / Display Tank (DT) Levels -- Confused.....

[thecoolguy]

*sorry for the long post....and thanks in advance for reading*

system: 1.5" herbie drain via hole in back of tank with elbow up, then sideways, then elbow down (just an elbow up would cause micro whirlpools no matter how dialed down the valve was...) and due to sump size, i needed to be able to stop the siphon earlier via a hole in the down elbow slightly below waterline

ok, so for the past month or so, all was 100% fine - the flow was dialed, full siphon was perfect, levels always constant

now, something has changed, and im confused.....(i obviously havent touched the valves or anything)

before: i would set the sump water level @ 10" (for example), and it remained constant - i did this by closing a secondary valve on the drain until the water was at the level i wanted, then opened it up

now: regardless of where i "set" the sump level, it wont equalize until 13" (for example - meaning more water in the sump)

even when i close the secondary valve 100% to let the pump drain out water from the sump to where it is back @ 10" - it will rise to 13" and then stay there

now, given the overflow and pump are still balanced perfect (once sump levels, it stays there indefinitely) - i am assuming all is well

but now the annoyance is - the small hole i drilled in the down elbow of the herbie drain in the tank to stop the siphon early, sucks in air every 10-15 seconds because the water level in the DT is lower

so......i added water to the DT thinking because the flows are already level, the water would stay in the DT - but no....it finds its way into the sump and raises the sump level....

im sure im missing some critical understanding of this all....someone please help me!

given the herbie is a full siphon - increasing the water level in the DT wouldn't increase its flow would it? meaning, do i have too much water in the entire system?

blah......im lost.....

 

[jcardona1]

Pictures would really help. I'm at a loss trying to visualize what you're describing. But I can tell you a true Herbie system shouldn't have any holes drilled in the line. That part confuses me.

 

[thecoolguy]

hey jose - here is a pic

as you can see - i drilled the hole so that the siphon would break before reaching the bottom of the down elbow

what you see is as if you are looking straight into the tank (basically an inverted "U")

 

[jcardona1]

Where is your valve placement? And your second emergency drain?

 

[thecoolguy]

not pictured

1) emergency drain is via another bulkhead with an up elbow - no worries there

2) valves are @ the sump per the norm

 

[jcardona1]

My thoughts are that all those elbows are messing with the flow of things. Do you have any water trickling down your emergency drain? When running a true full siphon at overflow's maximum capacity, you should have a small amount of water going down the emergency line. If the water level in the sump rises will the level in the tank drops, that tells me that the valve on the main drain needs to be closed off more (I think). But like I mentioned, I have a feeling it's all those up and down elbows that are screwing with your system.

 

[LoganBlade]

COUld the return pump be slowing? IF it slows down the water exiting would rise I think. just an idea.

 

[thecoolguy]

thanks for the help jose, some questions

1) water does not enter my emergency drain - i have always kept it about .75" above the waterline -- why would water going down the emergency line indicate a full siphon?

* isn't water going down the e-drain fully dependent on the water level in the tank? (or in the overflow, for tanks with overflows) -- i.e. if my main drain was 10" below the waterline, and obviously @ full siphon, and my e-drain was 10" above the waterline, i will still be at 100% siphon, no? *

2) the water level is "constant" in the tank and sump -- its just that i can't raise the water level of the tank for some reason? i add water into tank, and it raises the sump level - once it levels - nothing fluctuates, which tells me the main drain/valve is tuned correctly to match the pump and flow?

if i close the valve (ball valve w/ mallet adjustment that took a long time!) any more - then the flow will no longer match the pump output, therefore slowly draining the sump

so, i am thinking

* rear drilled tanks running herbie, may behave slightly differently from those that have overflow boxes either in/out of the tank
* my addition of 3-4 elbows may be affecting the siphon slightly

but, im still confused on why the tank/sump level does not fluctuate once it reaches a certain level

oh, another thing - as filter socks clog - sump level typically slowly decreases correct?

 

[Jc1119]

Odd. The only things on mine that affect the level in the sump at all, are the gate valve and how dirty my socks are. Display level never changes since Im using overflows with weirs.

You said the display level is lower? Is your pump output the same or has anything changed on that side? If you have less water in the display, i would suspect something on your return end. If your pump was pumping less, for some reason, your sump level would rise as well.

It might not be on the drain side at all.....

Check power and your pump(s) first. I know when I've run mine one one pump, the display level drops and the sump rises in mine

 

[thecoolguy]

and the confusion grows.....

im finding some answers from the RC guys....will chime back in when my head is a bit clearer.....

but it seems like in a system with just bulkheads to drains (no overflow boxes) - the system will level off where it levels off....with excess water dropped into tank (just like an overflow box) finding its way to the sump

as for pump power ---- not the problem, as the sump level is not moving/fluctuating - it has just found a new "level" - which i now think is simply because i have too much water in the system...