Will my tank flood?
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Scotty LaBeouf
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Thanks for the suggestions thats clever, although I have the return so low because im trying to hide every bit of filtration possible. also to hide the return into the tank it will exit into the tank under this mini tide pool shelfI would remove that elbow going into the bulkhead, use a T to extend it above the waterline and do something like this.
Taken from @143MPCo build thread.
hybridazn
Acro killer.....
Thanks for the suggestions thats clever, although I have the return so low because im trying to hide every bit of filtration possible. also to hide the return into the tank it will exit into the tank under this mini tide pool shelf
You could always elbow it back into the overflow, I'm sure there is a way to make this work. Time to get creative!
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Scotty LaBeouf
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yes i like creative thats what this tank is all about! Man ive never gotten so many quick responses thanks everyone! So what do you mean elbow it back into the overflow?
Drilled holes and check valves are both a false sense of security and can and do fail. All it takes is a piece of sand, flake of food, baby snail, algae or anything to keep a check valve from seating. It does not have to be a catastrophic failure, even a trickle will flood given time in a power outage situation (which usually according to old Murphy is in the middle of the night or when you are away from home!). Drilled holes can be defeated by lack of cleaning and maintanance, food sucking up against the hole, s snail, an anemone, algae, a small fish or anything.
The only foolproof method of controlling backsiphonage or backflow is the simplest thing known to man, an air gap. Stick a black 90 degree elbow on that return and get it up closer to the surface or plug that bulkhead hole and move it up. The next best solution is a larger sump as already suggested. Once the level drops to the bulkhead the siphon breaks and flow stops, it canot be defeated and it is foolproof since we all know water cannot jump uphill.
It is simple to calculate how much freeboard or spare room you will need in the sump by using L x W x H /231. You said the H is 2.5" so provide the other two measurements and divide it by 231 to see how much larger your sump would need to be to contain that 2.5 vertical inches of water in a power outage. My 100G mixed reef has the returns 3/4" below the surface and the tank is 60" L x 18" W so 60 x 18 x 0.75 / 231 = 3.5 gallons of spare room in the sump needed t contain the backflow worst case.
I don't like worrying about floods so no check valves or drilled holes to maintain, only to have plug of fail 5 minutes later. The current system has been set up over 13 years and never lost a drop on the floor from a backflow.
The only foolproof method of controlling backsiphonage or backflow is the simplest thing known to man, an air gap. Stick a black 90 degree elbow on that return and get it up closer to the surface or plug that bulkhead hole and move it up. The next best solution is a larger sump as already suggested. Once the level drops to the bulkhead the siphon breaks and flow stops, it canot be defeated and it is foolproof since we all know water cannot jump uphill.
It is simple to calculate how much freeboard or spare room you will need in the sump by using L x W x H /231. You said the H is 2.5" so provide the other two measurements and divide it by 231 to see how much larger your sump would need to be to contain that 2.5 vertical inches of water in a power outage. My 100G mixed reef has the returns 3/4" below the surface and the tank is 60" L x 18" W so 60 x 18 x 0.75 / 231 = 3.5 gallons of spare room in the sump needed t contain the backflow worst case.
I don't like worrying about floods so no check valves or drilled holes to maintain, only to have plug of fail 5 minutes later. The current system has been set up over 13 years and never lost a drop on the floor from a backflow.
TheEngineer
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I agree with AZDesertRat. There is no way I'd have any sort of setup that relies on a hole or a check valve to prevent a flood. Having a hole to break the siphon is great to reduce the amount of backflow, but it is by no means an effective way to prevent a backflow. Your sump should always be sized to allow the amount of backflow (plus some space) from your DT. I get it that yours is not and you don't want to make a new sump or change your bulkhead location. You need a way for air to get into your return line so that water will stop flowing, that much is clear. HOWEVER, you also need to make sure gravity won't take over and allow the water to flow anyway. The question for you is how to do it so that it is unobtrusive to your aesthetic. The only way you will prevent a flood in a reliable manner is to have the return line sit at a point that is high enough in your tank so that your sump can handle the backflow.
The idea of using a loc-line (or something similar) to bring the return closer to the surface of the water is a good one and the only one I would trust. You might need to rethink your aquascape a bit so you can accommodate a return higher up. hibridazn's idea is a good concept, but there will still be backflow. Water will drain to the lowest point gravity will allow whether or not there is a siphon actively pulling the water. While his idea will break the siphon, it won't stop the flow of water.
The idea of using a loc-line (or something similar) to bring the return closer to the surface of the water is a good one and the only one I would trust. You might need to rethink your aquascape a bit so you can accommodate a return higher up. hibridazn's idea is a good concept, but there will still be backflow. Water will drain to the lowest point gravity will allow whether or not there is a siphon actively pulling the water. While his idea will break the siphon, it won't stop the flow of water.
Loc line is not always water or air tight and a risky solution. As the ball joints age they get dirty and get corraline build up on them which breaks the seal. As you flex or move the Loc line it scratches the plastic and over time it leaks. Sort of like the drilled holes, it will slow the backflow to a trickle but in time you will have water on the floor, in the middle of the night when only the wife is at home and you are in deep doo doo. Don't aske me how I know this and it wasn't the sump or display but it may have been an RO or ATO storage attempt but I will never admit to it.
Keep It Simple. Nothing to maintain and nothing to fail. We all get ahead of ourselves sometimes and hindsight is 20/20, like the old measure twice and cut once saying. If it is worth doing, it is worth doing right the first time. Correct it now and sleep soundly at night.
Keep It Simple. Nothing to maintain and nothing to fail. We all get ahead of ourselves sometimes and hindsight is 20/20, like the old measure twice and cut once saying. If it is worth doing, it is worth doing right the first time. Correct it now and sleep soundly at night.
TheEngineer
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EDITED
I re-read what you said and I think what you're saying is that loc-line will beat the siphon, but you could still have a leak through the joints. This is true, no arguments from me.
Yes.Loc line may be water tight when new but as it ages it loosens up or builds up and that seal goes away. Not a good long term idea to raise a return and prevent backsiphonage.
You can have your return line go up and use the lock lines .just have them set just below your water line in tank.when power drops the siphon will break as soon as the opening of the lines are exsposed to air,I have this on my 375,never had a problem.the inside pipe in tank you can use gray schedule 80 pipe so it's not white.
john.m.cole3
cyclOps
Could you post a picture of this. I'm having a hard time visualizing this...
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john.m.cole3
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Ok, so it would only apply for the drain portion. I thought he meant in the return some locline is discussed next. This would not apply to me bc I'm running a ghost overflow
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The OP is asking how he can prevent a flood given that the bulkhead for his return is significantly below the waterline.
Drill your top elbow into your return and install a drip emitter fitting and run a the drip tube from the emitter fitting to make a top lupe inside the overflow box for your anti siphon. A 1/8 tube emitter will do just fine and break the siphon when the return pump is off
john.m.cole3
cyclOps
I was sleepy when I posted this. Sorry to be off topic.
Now I am more awake and mostly get it, but wouldn't adding a black 90 that points up make your return water pressure point upwards also. I'm guessing @AZDesertRat has done this before w/o water shooting up and out of the tank, but that was/is whay I was having a hard time imagining this. great idea!
I didn't know locline could fail. And that equation to determine extra sump space is quite helpful.
Ya'll have a nice weekend!
This tank is not going to back-siphon, it's going to DRAIN. (assuming the check valves fail)
(well, it is going to back-siphon as well, but even if the siphon is defeated, the tank is going to drain down to the level of the bulkhead fixture in the overflow. No siphon required.)
You need your supply line to go up past your bulkhead fixture, have a siphon break at the apex of the line, and then back down to the bulkhead. This means you'll probably have to use a smaller diameter piping in order to fit it all within your overflow. A couple of 45s and three 90s should allow you to step-aside your pipe as it comes in the bottom of the tank, and make an inverted U at the top, and then back down and out your bulkhead. A small hole on the bottom surface of the inverted U will keep a continuous (and easy-to-verify clear and open) stream of water that shoots downward, back into your overflow.
The other plan B is to install an overflow bulkhead in your sump that drains into a container that's large enough to hold a lot of water. But that's really not ideal because you'll permanently lose nearly half of your DT volume if there's a power failure. When power is restored, your return pump will run dry unless you have it on a controller that considers sump level.
Simple solution that achieves your goal: Smaller diameter return piping, allowing an inverted U with a siphon break, all neatly contained within your overflow.
(well, it is going to back-siphon as well, but even if the siphon is defeated, the tank is going to drain down to the level of the bulkhead fixture in the overflow. No siphon required.)
You need your supply line to go up past your bulkhead fixture, have a siphon break at the apex of the line, and then back down to the bulkhead. This means you'll probably have to use a smaller diameter piping in order to fit it all within your overflow. A couple of 45s and three 90s should allow you to step-aside your pipe as it comes in the bottom of the tank, and make an inverted U at the top, and then back down and out your bulkhead. A small hole on the bottom surface of the inverted U will keep a continuous (and easy-to-verify clear and open) stream of water that shoots downward, back into your overflow.
The other plan B is to install an overflow bulkhead in your sump that drains into a container that's large enough to hold a lot of water. But that's really not ideal because you'll permanently lose nearly half of your DT volume if there's a power failure. When power is restored, your return pump will run dry unless you have it on a controller that considers sump level.
Simple solution that achieves your goal: Smaller diameter return piping, allowing an inverted U with a siphon break, all neatly contained within your overflow.
