posiden
Active Member
Ok, with some assumptions on my part I have come up with a little info. This is gonna melt your mind.
As mentioned, when the system is not running but full of water. Your DT will have a water level in it that is right at the bottom of the teeth on the OF. When you fire up the return pump water will then spill into the OF box and then out the drain pipe. The extra water in the system will be seen when the system is running. You will see this extra water at your OF. I mentioned that teeth provide extra resistance and therefore causing more water to deal with when the pump shuts off for what ever reason. After a little math......your tank runs about 4.783 gallons of water for every 1" in height. This is kinda important to know because of the back flow question. Here's why. With your OF with the teeth on it, it will cause the water to rise about 5/8-11/16" before it levels off and runs steady. That is about 3.1 gallons of water. So......you need to plan on about 3 gallons draining from the display tank JUST in the OF side of things.
Your refug tank is going to be running a max capacity with very few ounces to spare or worry about. It wont contribute to any back flow water into the sump. To speak of. That's if you split the drain line. Your wont be running much through there.
Now, you need to look at the return line. Just the pipe alone will hold about .115 gallons (or 14.72oz) Not too big of a deal there. But that will change if the output of the return line is farther under water then the bottom part of the teeth on the OF. So, if you keep the outputs up high.....you wont need to worry about this "much". With a DT level running about 5/8" above the bottom of the teeth, your outputs "should" be easy to place in a safe place.
I wouldn't really worry too much about the amount of water in the drain line. It will be minimal. Again, only about the 14oz. at the most. Your drain will need air in it to remain quiet during operation. You will want the water to coat the walls of the pipe. That's why its been mentioned to have a bigger then needed drain. Which is why I mentioned the Herbie. Full siphons don't need or use air to run silent.
Your 20L is going to be the one that holds all of the back flow. Going by its dimensions, internally. Cause I have one here sitting on the floor. It will hold a max of 17.25 gallons. Giving you 1.5 gallons of water for every 1" in height. So figuring a back flow on the minimum side of 3.5 gallons of water. You will need 2.34" (I would figure 2.5-3") of full tank that is unobstructed for the head height needed. This is a bare minimum IMO. A little extra wiggle room is always welcome. So your baffles at 9" tall all the way across is the very tallest your gonna want your baffles to be IMO.
On a side note. I mentioned about teeth causing more back flow issues. If you were running a smooth OF (no teeth) the water level would only rise by about 5/16" or 1.49 gallons of water. A little less then half the amount of water to worry about. However, like anything else. That route has its pros and cons. It wont keep you livestock out of the OF like teeth will. You take the good with the bad.
I'll draw something up for you. No problem. It will be a pic of paper cause I'm luck to be able to type on these computers. Take care man.
Edit a day later; I forgot to mention that this is all based on 650ish GPH. If you run more water things will change and the level will rise a bit more. Also the opposite will happen if you run lees water. So, depending on how big of a pump you buy and how much you actually get from it comes into play.
As mentioned, when the system is not running but full of water. Your DT will have a water level in it that is right at the bottom of the teeth on the OF. When you fire up the return pump water will then spill into the OF box and then out the drain pipe. The extra water in the system will be seen when the system is running. You will see this extra water at your OF. I mentioned that teeth provide extra resistance and therefore causing more water to deal with when the pump shuts off for what ever reason. After a little math......your tank runs about 4.783 gallons of water for every 1" in height. This is kinda important to know because of the back flow question. Here's why. With your OF with the teeth on it, it will cause the water to rise about 5/8-11/16" before it levels off and runs steady. That is about 3.1 gallons of water. So......you need to plan on about 3 gallons draining from the display tank JUST in the OF side of things.
Your refug tank is going to be running a max capacity with very few ounces to spare or worry about. It wont contribute to any back flow water into the sump. To speak of. That's if you split the drain line. Your wont be running much through there.
Now, you need to look at the return line. Just the pipe alone will hold about .115 gallons (or 14.72oz) Not too big of a deal there. But that will change if the output of the return line is farther under water then the bottom part of the teeth on the OF. So, if you keep the outputs up high.....you wont need to worry about this "much". With a DT level running about 5/8" above the bottom of the teeth, your outputs "should" be easy to place in a safe place.
I wouldn't really worry too much about the amount of water in the drain line. It will be minimal. Again, only about the 14oz. at the most. Your drain will need air in it to remain quiet during operation. You will want the water to coat the walls of the pipe. That's why its been mentioned to have a bigger then needed drain. Which is why I mentioned the Herbie. Full siphons don't need or use air to run silent.
Your 20L is going to be the one that holds all of the back flow. Going by its dimensions, internally. Cause I have one here sitting on the floor. It will hold a max of 17.25 gallons. Giving you 1.5 gallons of water for every 1" in height. So figuring a back flow on the minimum side of 3.5 gallons of water. You will need 2.34" (I would figure 2.5-3") of full tank that is unobstructed for the head height needed. This is a bare minimum IMO. A little extra wiggle room is always welcome. So your baffles at 9" tall all the way across is the very tallest your gonna want your baffles to be IMO.
On a side note. I mentioned about teeth causing more back flow issues. If you were running a smooth OF (no teeth) the water level would only rise by about 5/16" or 1.49 gallons of water. A little less then half the amount of water to worry about. However, like anything else. That route has its pros and cons. It wont keep you livestock out of the OF like teeth will. You take the good with the bad.
I'll draw something up for you. No problem. It will be a pic of paper cause I'm luck to be able to type on these computers. Take care man.
Edit a day later; I forgot to mention that this is all based on 650ish GPH. If you run more water things will change and the level will rise a bit more. Also the opposite will happen if you run lees water. So, depending on how big of a pump you buy and how much you actually get from it comes into play.
