This might be a really stupid question but what are the advantages of having a drilled tank for a sump vs. an overflow? Wont both flood your room if the power goes out if you dont drill a siphon break in the return line?
Sump...advantages of drilled tank?
- Thread starter Bristlenose Chuck
- Start date
it wont flood if you have the right size sump. i think some overflow boxes are made to restart the siphon if it stops but with a drilled tank i dont worry cause once the sump water goes into the tank it just flows back down.
Well, I think I might get it now.
With a drilled tank you only have to worry about the sump overflowing if the power goes out. this can be easily taken care of if you leave enough room in the sump for the extra water.
For a HOB overflow you have to worry about the main tank overflowing right? This would happen if the siphon failed and the return pump continued to push the sump water up to the display tank.
Do I have it right?
With a drilled tank you only have to worry about the sump overflowing if the power goes out. this can be easily taken care of if you leave enough room in the sump for the extra water.
For a HOB overflow you have to worry about the main tank overflowing right? This would happen if the siphon failed and the return pump continued to push the sump water up to the display tank.
Do I have it right?
You can and should never rely on the function of the return pump to keep the sump or tank from overflowing. Power outages happen. Pump clogs and/or failures happen.
Any technique for moving water from one tank to another should be fail-safe. Power off situations should be assumed, and in the reality the tank should stop draining down at the point determined by the height of the standpipe in an external over-the-side or bottom drilled standpipe/constant level siphon setup, by the position of the drain bulkhead in a through-the-side drilled setup or of the constant-level siphon or standpipe beyond it, and the sump must be of sufficient size/footprint to accept that power-off drain down volume of water from the display without overflowing. To have a setup done otherwise guarantees a flood.
Any technique for moving water from one tank to another should be fail-safe. Power off situations should be assumed, and in the reality the tank should stop draining down at the point determined by the height of the standpipe in an external over-the-side or bottom drilled standpipe/constant level siphon setup, by the position of the drain bulkhead in a through-the-side drilled setup or of the constant-level siphon or standpipe beyond it, and the sump must be of sufficient size/footprint to accept that power-off drain down volume of water from the display without overflowing. To have a setup done otherwise guarantees a flood.
Even the most thorough fail-safes fail...and to believe otherwise is asking for trouble.
Based on what I've been reading on sumps and sump design lately, in a properly design HOB filter, the bigger worry isn't in the siphon breaking but in it getting clogged or the drain into the sump getting blocked (A fish gets in the wrong place at the wrong time...a large piece of vegetation...etc). Besides the "egg-crate" method to help prevent this, it is also recommended to have two paths for the water to flow to the sump in case one DOES get blocked. The main tank -will- flood if water is somehow prevented from getting to the sump while the power is on...that's a risk you take when setting up these things.
When the power is off, as long as you have enough space for all the water in the pipes to drain back down into the sump without the sump overflowing, you should be fine. You must also worry about any water the outlet from the sump siphons back down into the sump, but this can usually be prevented with a check valve and/or a few siphon-break holes. Again, there's always a risk, but the risk is minimal when proper planning is done.
Remember, there's always a chance that the glass/acrylic will one day give out on the tank. We trust that it won't because it doesn't happen often and strong enough bonds/materials are used to help prevent it...but the risk is always there. When you have large amounts of water in a small area, you're always risking a flood.
Based on what I've been reading on sumps and sump design lately, in a properly design HOB filter, the bigger worry isn't in the siphon breaking but in it getting clogged or the drain into the sump getting blocked (A fish gets in the wrong place at the wrong time...a large piece of vegetation...etc). Besides the "egg-crate" method to help prevent this, it is also recommended to have two paths for the water to flow to the sump in case one DOES get blocked. The main tank -will- flood if water is somehow prevented from getting to the sump while the power is on...that's a risk you take when setting up these things.
When the power is off, as long as you have enough space for all the water in the pipes to drain back down into the sump without the sump overflowing, you should be fine. You must also worry about any water the outlet from the sump siphons back down into the sump, but this can usually be prevented with a check valve and/or a few siphon-break holes. Again, there's always a risk, but the risk is minimal when proper planning is done.
Remember, there's always a chance that the glass/acrylic will one day give out on the tank. We trust that it won't because it doesn't happen often and strong enough bonds/materials are used to help prevent it...but the risk is always there. When you have large amounts of water in a small area, you're always risking a flood.
Thanks for the help
After endless searching online I think I finally found some really good explanations of what a sump is and how they work. They are written more for a saltwater tank but the idea still applies to Freshwater.
http://www.melevsreef.com/what_sump.html
http://reefkeeping.com/issues/2003-01/gt/index.php
I hope those help others who are interesting in learning more about sumps.
After endless searching online I think I finally found some really good explanations of what a sump is and how they work. They are written more for a saltwater tank but the idea still applies to Freshwater.
http://www.melevsreef.com/what_sump.html
http://reefkeeping.com/issues/2003-01/gt/index.php
I hope those help others who are interesting in learning more about sumps.
LesbianChap said:
When your power comes back on and the pump starts to put the water back in the display tank you're in trouble right? The siphon would be broken when the power went out therefore the water would not drain back down to the sump and you would overflow your dispaly right?
Not if you design your HOB overflow right. Basically, you're making a water-bridge between the display tank and a smaller HOB tank. In order to keep the siphon from breaking, you create a small tank in the display tank below the water line (Remember reading about skimming area?). You do the same in the HOB tank (a small compartment that the siphon is in that will always have water, that overflows into a drain compartment).
The only way the siphon will break is if you have an airstone blowing bubbles into it. With a properly designed skimmer, this is highly unlikely (and less-so during a power outage). The only other thing you have to worry about is vegitation or fish blocking the siphon...which is solved by putting an egg-crate over the skimmer (to keep stuff out) and, if you can afford the space, making two siphons.
This site has some (poor) animations that show the process: http://www.cyberreefguru.com/general/overflow/overflow.html
http://camelreef.free.fr/decant/index.htm has an interesting design, unfortunately it's in what looks like French to me.
And one of the best diagrams I've found:
http://www.csd.net/~cgadd/aqua/overflow.htm
The only way the siphon will break is if you have an airstone blowing bubbles into it. With a properly designed skimmer, this is highly unlikely (and less-so during a power outage). The only other thing you have to worry about is vegitation or fish blocking the siphon...which is solved by putting an egg-crate over the skimmer (to keep stuff out) and, if you can afford the space, making two siphons.
This site has some (poor) animations that show the process: http://www.cyberreefguru.com/general/overflow/overflow.html
http://camelreef.free.fr/decant/index.htm has an interesting design, unfortunately it's in what looks like French to me.
And one of the best diagrams I've found:
http://www.csd.net/~cgadd/aqua/overflow.htm
the main concern with hob overflows is siphon losing suction. im not worried about flooding becuase that wont happen if its designed right. im just worried about losing suction and then without more water flowing back into the sump im going to burm out a waterpump.