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Unread 05/16/2019, 05:34 AM   #1
hothit
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Is this overflow system gonna work?

I'm planning to make this overflow for my tank. the goal is to drain from bottom.

in theory it will work but in real world i'm a bit worried about the noise that "air in" is going to make and where water level is going to be when power goes off.


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Unread 05/16/2019, 11:50 AM   #2
Dsekula
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If that is a front view with the water exiting from the bottom of the tank and going up then to the sump then that won't work, you need a baffle before the drain line so that the water cannot complete drain from the tank and the line should not go up to the top of the tank or over or water will not drain as it won't flow up. To get the air in behind the baffle you want a line sticking up into the tank with a T, the lower area will let water in and higher will let in air. To make it silent you need a second drain line. The second line would be your main line and stay at a true vacuum while the other would pull air.

Here's a link from Marine Depot that give a better explanation than I can

https://blog.marinedepot.com/educati...nimal-overflow

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Unread 06/11/2019, 06:57 AM   #3
nematode
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Yes, this would work.
If the water pump is in your sump this will work as long as the air in is large enough to fully break a siphon. Essentiallly in this case the wall of the tank is acting as the baffle.
This is a dangerous way to run an overflow as there is no secondary safety feature to prevent one of two potential issues.
1) drain is blocked - pump floods tank emptying the sump
2) air in is blocked - tank drains and sump floods.


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Unread 06/11/2019, 06:59 AM   #4
nematode
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Noise level will depend on the flow relative to pipe size
Water level when off will be bottom of horizontal tube section ar air in or bottom of water in tube if that is lower ( will back siphon).


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Unread 06/11/2019, 02:28 PM   #5
Dsekula
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The points others posted are valid about either the dt or sump running dry. But, the point some of you seem to either be missing or assuming the op just drew inaccurate is that water will not drain upwards (above the fill line of the tank) at high velocity some will travel up but designing that tank assuming this continuous flow is maintained after an anti syphon device (air inlet) would be poor planning. I attached an altered picture of the ops design if I'm articulating this poor. This would work but still lacks the fail-safes mentioned before.

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Unread 06/11/2019, 03:28 PM   #6
nematode
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Dsekula is correct that the original drawing has the horizontal run of the outlet too high. I was just assuming that the original drawing was a little sloppy, but it is certainly very worthwhile for Dsekula to clarify this.


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Unread 06/11/2019, 05:24 PM   #7
BrettDS
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One other thing to consider is that by not using an overflow you will get no surface skimming. When I designed my sump I originally designed it so the water would flow out of the fuge by flowing under a baffle. But this left the top of the water in the fuge stagnant and within a week or two all kinds of nasty oil and stuff built up on the water’s surface. In your main tank this will not only be ugly, but the oil will stop gas transfer and it could cause low oxygen levels in the water. You really need an overflow for it’s surface skimming.


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Unread 06/11/2019, 05:40 PM   #8
nematode
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I completely agree.
The way I run my Q tanks is to have 1/2 full tank (55g for example) and have a internal mechanical and biological filter that is made of a 4inch PVC tube with a tray on top that has a filter pad in it. I pump the water into the tray, and it then runs down the tube that is filled with porus glass hydroponic material, part of which is above the surface of the water and part below.
I use this approach because it is really simple to maintain allows me to have a low volume tank with lots of swim space, but keeping volume down for medicating.
Very effective for filtering, but the water surface gets scummy with oily material over time. That is really the only significant drawback (and that once one of my dartfish jumped into the tray on top (It is now covered).


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