Inline filter

[Ulu]

I have about eight tanks running & the overflows are all different on the ones with sumps but the one common thing about them is there's an inside pipe that sets the height. Engineers call it a weir, which just means a low Dam that the water flows over the top as it drops a little.

Aquarists can call it an overflow but usually that term means the part on the outside of a tank.

 

[Ulu]

This is my latest tank and it does not have a weir, yet it does, because it is bottom drilled with a 1.5" drain pipe and a valve.

When you open that valve, the entire 75 gallons will not drain into the sump. Once again the top of the pipe sets the water level.

 

[johnnymax]

The bottom of the Tee fitting is the overflow pipe which will maintain the water level.
I am a civil draftsman and have designed many weirs for detention ponds.
I designed it with an overflow pipe not a weir. A weir is narrow on the bottom and gets wider as it goes up. It is in the shape if a V which allows more water to flow through it the deeper it gets allowing for 100 year flood rain events.

 

[Dloks]

Engineer vs engineer who shall win

 

[johnnymax]

Engineer vs engineer who shall win

No interest in winning...
I just try to design things as simple and affordable as possible. It must be the Scott in me, makes me "Cheap" The wife says "Frugal"

 

[BichirKing]

what happens if you lose the prime in your overflow tube? doesn't look like a way for it to self prime?

 

[johnnymax]

The white PVC tube inside the tank is my weir, and you cut it to approx your desired water depth. I cut mine a little short and then I have a foot on the bottom of the tube which I can use to weight it down in the tank...

I took a close look at your setup. I am doing the same thing. The difference is I have my "weir" outside the tank and you have yours inside the tank. The siphon hose I have keeps the level in the pipe outside the tank the same as the tank.
When water is added to the tank and the level rises, so does the level in the pipe outside because of the siphon.
As the level in the outside pipe rises, it overflows through the overflow pipe (or weir) which in turn removes water from the tank above the elevation of the overflow.
This was the simplest way I could design an automatic water changer. I am always open to ideas to make things Simpler

 

[johnnymax]

what happens if you lose the prime in your overflow tube? doesn't look like a way for it to self prime?

That was a real concern. So, I need to have both ends of the siphon secured well below the water level, or I will have tank overflow.
But it will function even if the power is off.

 

[Ulu]

The bottom of the Tee fitting is the overflow pipe which will maintain the water level.
I am a civil draftsman and have designed many weirs for detention ponds.
I designed it with an overflow pipe not a weir. A weir is narrow on the bottom and gets wider as it goes up. It is in the shape if a V which allows more water to flow through it the deeper it gets allowing for 100 year flood rain events.

My friend, I never did hydrology professionally. I do know there are different kinds of weirs for different applications, and some serve multiple applications. If I seem scatterbrained, you'll have to forgive me. I've been keeping long hours remodeling and the brain is tired.

For such a low flow as yours though it won't do much more than a sponge or strainer. You won't get aeration, which is real benefit to me.

I was totally panicking over the long siphon. Long siphon tubes freak me out for several reasons. As long as the air break is open it can't drain the tank. Your real problem is keeping the drain clear.

Low flow, plus long tube, plus buildup of bio-film, means rapid increase in restriction for small tubes.

 

[johnnymax]

My friend, I never did hydrology professionally. I do know there are different kinds of weirs for different applications, and some serve multiple applications. If I seem scatterbrained, you'll have to forgive me. I've been keeping long hours remodeling and the brain is tired.

For such a low flow as yours though it won't do much more than a sponge or strainer. You won't get aeration, which is real benefit to me.

I was totally panicking over the long siphon. Long siphon tubes freak me out for several reasons. As long as the air break is open it can't drain the tank. Your real problem is keeping the drain clear.

Low flow, plus long tube, plus buildup of bio-film, means rapid increase in restriction for small tubes.

Yes your right a weir can me flat (like a dam) I thought I was addressing the issue of my system draining my tank dry???
I understand, our systems are different and serve to different purposes. Mine is not for filtering or aeration. It is just to allow water to slowly flow out as fresh filtered water flows in from the tap. I will adjust the water going in to be very slow, about 5 gallons over an hour once per day.
I aerate and filter in the tank.
The pre-filter on the end of the hose is to make sure nothing gets sucked up into the siphon like sand, etc. as water flows out of the tank and to my garden outside.
It is just an "Automatic Water Changing System" so I don't have to do water changes manually every weekend.
Thanks for the tip, I won't use a siphon hose too small. I am using clear hose so I can see if there is any build up that could clog it. Once water leaves the tank the line it goes through will be garden hose. Without light it should not have much growth. Maybe I could flush it periodically.

Good luck on the remodel and take care of that brain...