So what stops the return from back syphoning when the power goes out? and if the returns are under the sand doesn't the water flow blow the sand out of the way to reveal the nozzels?
Plumbing questions.
- Thread starter krytan
- Start date
There will be no back siphoning from the return nozzles in a closed loop, simply because it is going to a pump--there is nowhere to flood. If you are referring to the return pump from the sump, the best idea is to have any returns close to the surface of the water. They do make check valves that work well, but the question there is for how long. I have had check valves fail enough that I don't use them any longer.
Right...you can put your CL intakes and returns anywhere you want because its a closed system. Again, think of a canister filter. When you unplug your canister, does the tank overflow or flood anywhere? No, because its a closed system - no place for the water to go.
With the return line from your return pump, I would recommend a siphon break - a small hole (or several for redundancy) drilled just below the water line. When the power goes out, the water level drops a few mm and exposes the hole, letting air into the line and stopping the siphon. I agree with Amph...I wouldn't bet my floors on a check valve.
With the return line from your return pump, I would recommend a siphon break - a small hole (or several for redundancy) drilled just below the water line. When the power goes out, the water level drops a few mm and exposes the hole, letting air into the line and stopping the siphon. I agree with Amph...I wouldn't bet my floors on a check valve.
I agree, do make a siphon break. I meant to say that those are all I use now, in addition to the return being as close to the surface as possible (without splashing) for redundancy.
So if i was to have my returns on the bottom of the of the tank similar to how Niko has done do i not need a siphon break?
Also if the power went out i take it the overflow pipes would still empty into the sump on a closed loop system?
My understanding is that for 40mm bulk heads i need to drill 55mm holes in the tank, is this right? and do the measurements from different manufactures of bulkheads very? I'm asking because i would like to order the drill bit so i can get started.
Sorry for all of the noob questions but i think i'm getting to grips with it all now.
Also if the power went out i take it the overflow pipes would still empty into the sump on a closed loop system?
My understanding is that for 40mm bulk heads i need to drill 55mm holes in the tank, is this right? and do the measurements from different manufactures of bulkheads very? I'm asking because i would like to order the drill bit so i can get started.
Sorry for all of the noob questions but i think i'm getting to grips with it all now.
I don't think you're quite understanding the systems. A closed loop is completely independent of the sump and return pump. A closed loop has intake and outlet underwater, with an external pump in between them Water goes into a pipe from the tank, through the pump, and into another pipe back into the tank. Completely sealed system. This is what niko posted. You don't need a siphon break on this because there is no place for the water to siphon to (closed system).
A sump and return pump is totally separate. You will need an overflow (internal/drilled or HOB, doesn't much matter), a sump, a return pump, and some sort of return line. Water drains through the overflow, into the sump, goes through whatever the sump does (fuge, skimmer, reactors, etc), then the return pump pumps the water back up to the tank. This is the line that can siphon, so its the one you want a siphon break on. Any residual water in the lines will flow back into the sump, as well as any water that is above the level of the overflow, and above the level of the return line siphon break. You can usually get away with this volume only being a few gallons.
A sump and return pump is totally separate. You will need an overflow (internal/drilled or HOB, doesn't much matter), a sump, a return pump, and some sort of return line. Water drains through the overflow, into the sump, goes through whatever the sump does (fuge, skimmer, reactors, etc), then the return pump pumps the water back up to the tank. This is the line that can siphon, so its the one you want a siphon break on. Any residual water in the lines will flow back into the sump, as well as any water that is above the level of the overflow, and above the level of the return line siphon break. You can usually get away with this volume only being a few gallons.
The return would realistically (not total rated, but the actual flow you should have coming from the main pump) be something like 5x-8x, whereas the closed loop should be 10-20x+. I personally wouldn't bother with a closed loop that was under 20x turnover, though. Something like a Reeflo dart @ 3600 gph would be the minimum, IMHO.
Closed loop should be the majority of your turnover. Flow through the sump can basically be determined by your skimmer - there isn't much reason to put more flow through the sump than your skimmer will handle. If that ends up being 1200gph or whatever, then shoot for that through your sump. Go for 20-25x or more turnover with the closed loop.
Keep in mind, you can also get that turnover in the tank with powerheads, a closed loop isn't a requirement. You could just use some Koralia 3s and 4s, Tunze Streams, or any other number of powerheads available to make up that turnover rate as well. I am partial to closed loops because, on a nice display tank, I hate looking at powerheads stuck all over the place...just personal preference.
Keep in mind, you can also get that turnover in the tank with powerheads, a closed loop isn't a requirement. You could just use some Koralia 3s and 4s, Tunze Streams, or any other number of powerheads available to make up that turnover rate as well. I am partial to closed loops because, on a nice display tank, I hate looking at powerheads stuck all over the place...just personal preference.
The upside to powerheads vs. closed loop centrifugal pumps is energy efficiency. They use far less electricity (and less heat). For example, I can get more mass flow (high volume but far less velocity) than a Reeflo Hammerhead for ~28w. The trade-off is that you must look at them all the time, clean them more regularly, etc.
