SamH Posted March 24, 2010 Report Share Posted March 24, 2010 I'm trying to install an overflow system on a small tank but my trials so far have failed. Looking for some inspiration, ideas and/or comments on what you have, how it's worked out and how you did it. Drilling the tank is not an option unfortunately so no drilled tanks allowed. Any and all advice, photos and comments are welcome. Thanks! Quote Link to comment Share on other sites More sharing options...
smidey Posted March 24, 2010 Report Share Posted March 24, 2010 http://fishkeepers.co.nz/forums/viewtop ... low#p18055 here's a thread that may help Quote Link to comment Share on other sites More sharing options...
SamH Posted March 24, 2010 Author Report Share Posted March 24, 2010 http://fishkeepers.co.nz/forums/viewtopic.php?f=14&t=1869&p=18055&hilit=over+flow#p18055 here's a thread that may help but those all look drilled? Quote Link to comment Share on other sites More sharing options...
smidey Posted March 24, 2010 Report Share Posted March 24, 2010 it is an interesting concept not drilling for an overflow. would that not make it a syphon system? how about into a plastic bucket with media & a pump with a return pipe??? :lol: Quote Link to comment Share on other sites More sharing options...
R32GOTMLK Posted March 24, 2010 Report Share Posted March 24, 2010 viewtopic.php?f=28&t=44098 Quote Link to comment Share on other sites More sharing options...
smidey Posted March 24, 2010 Report Share Posted March 24, 2010 is there any advantage for a small tank like sam's to do a syphon overflow? a canister would be alot easier i would have thought. Quote Link to comment Share on other sites More sharing options...
SamH Posted March 24, 2010 Author Report Share Posted March 24, 2010 Well I have a spare, munted tank that'd be no good for a display and no heater for it. Killing two stones with one bird by using the same heater, already have a pump and acrylic for dividers so it's essentially a free filter. Plus I can use the extra space below for more plants and fish. http://www.fnzas.org.nz/fishroom/viewtopic.php?f=28&t=44098 Thanks! Quote Link to comment Share on other sites More sharing options...
Morcs Posted March 24, 2010 Report Share Posted March 24, 2010 You can actually buy syphon overflow units off ebay. Or you can make your own using a hang-on filter casing. Quote Link to comment Share on other sites More sharing options...
SamH Posted March 24, 2010 Author Report Share Posted March 24, 2010 Or you can make your own using a hang-on filter casing. Tell me more! I have a couple of spare HOBs, I never thought of that Quote Link to comment Share on other sites More sharing options...
Morcs Posted March 24, 2010 Report Share Posted March 24, 2010 Tell me more! I have a couple of spare HOBs, I never thought of that Ill have to google it, but basically you use the HOB casing, (empty) and drill a hole in the bottom to route the pipe for the syphon overflow. Quote Link to comment Share on other sites More sharing options...
Scottie841 Posted March 24, 2010 Report Share Posted March 24, 2010 Yep if you use a HOB and either drill a hole at the desired water level or a hole in the bottom and a pipe up to the water level you will have something like this Quote Link to comment Share on other sites More sharing options...
SamH Posted March 25, 2010 Author Report Share Posted March 25, 2010 So I use the HOB motor to draw water from the tank? If so, I need to cut the pipe down right? If not, then how do I get water into the HOB? Thanks! Quote Link to comment Share on other sites More sharing options...
Ira Posted March 25, 2010 Report Share Posted March 25, 2010 So I use the HOB motor to draw water from the tank? If so, I need to cut the pipe down right? If not, then how do I get water into the HOB? Thanks! No, it siphons out of the main tank into the hob. As long as the main tank water level is higher than the hob the water will siphon out. Quote Link to comment Share on other sites More sharing options...
SamH Posted March 25, 2010 Author Report Share Posted March 25, 2010 Ira, will try some tests tonight Quote Link to comment Share on other sites More sharing options...
spoon Posted March 25, 2010 Report Share Posted March 25, 2010 you could use the hob motor at the start to prime the u-tube but you will need to turn it off quickly and block your outlet tube when you do this until the you tube is full Quote Link to comment Share on other sites More sharing options...
SamH Posted March 25, 2010 Author Report Share Posted March 25, 2010 I was planning on priming with HOB motor Block the outlet? I was planning on having the outlet slightly higher than the end of the U tube in the HOB. Quote Link to comment Share on other sites More sharing options...
SamH Posted March 25, 2010 Author Report Share Posted March 25, 2010 So let's see if I have this right. Water flows through the U tube into the HOB casing and only reaches the top of the "To Sump" pipe before draining down to the sump. The water level in the tank will not rise further than the height of the "To Sump" pipe and the U tube will siphon more water so long as the water level in the HOB casing is lower than in the tank. Right? Quote Link to comment Share on other sites More sharing options...
Ira Posted March 25, 2010 Report Share Posted March 25, 2010 Yup. There will be some differences in water levels of course due to limitations of flow rates but close enough. Quote Link to comment Share on other sites More sharing options...
SamH Posted March 25, 2010 Author Report Share Posted March 25, 2010 but close enough Is close enough okay? Does it matter that the HOB is rated 370lph (not using the motor but still) and the return pump is rated 500lph? Also, what should the diameter of the pipe to sump be? Quote Link to comment Share on other sites More sharing options...
ryanjury Posted March 25, 2010 Report Share Posted March 25, 2010 He means close enough in that the tank water level will always be higher than that in the overflow (or HOB filter in this case) in order for the siphon to work, have you ever tried to siphon water uphill? The bigger the size of the U coming out of the tank the less difference there will be. I would also recommend having 2 siphon tubes into your HOB filter just in case one gets some air bubbles in it or something happens and it stops working. The rating of the motor in the filter means nothing the max flow rate will be governed by the size of the pipe to the sump and the size of the pipes out of the tank. Quote Link to comment Share on other sites More sharing options...
Ira Posted March 26, 2010 Report Share Posted March 26, 2010 He means close enough in that the tank water level will always be higher than that in the overflow (or HOB filter in this case) in order for the siphon to work, have you ever tried to siphon water uphill? The bigger the size of the U coming out of the tank the less difference there will be. I would also recommend having 2 siphon tubes into your HOB filter just in case one gets some air bubbles in it or something happens and it stops working. The rating of the motor in the filter means nothing the max flow rate will be governed by the size of the pipe to the sump and the size of the pipes out of the tank. Also what some people have done is put a small nipple at the top of the U and run it to a powerhead with a venturi inside the tank. The venturi will then suck a tiny bit of water out of the U constantly, not enough to matter though. But if air starts to collect in it then the air just gets sucked out. Might even be enough to start the siphon on its own, given time. Quote Link to comment Share on other sites More sharing options...
SamH Posted March 26, 2010 Author Report Share Posted March 26, 2010 Thanks for the tip Ira The pump came with a 10mm attachment so I'll hook some 10mm Boston tubing onto that, not too sure how to put it in the tank without it kinking though. Would a 20mm bulkhead be too much? Can I use Boston tubing attached to the bulkhead? Quote Link to comment Share on other sites More sharing options...
SamH Posted March 28, 2010 Author Report Share Posted March 28, 2010 Hold on, how does the HOB system regulate the amount of water going out of the tank? Or does it just take water without regulating it? Thanks Quote Link to comment Share on other sites More sharing options...
Ira Posted March 28, 2010 Report Share Posted March 28, 2010 Hold on, how does the HOB system regulate the amount of water going out of the tank? Or does it just take water without regulating it? Thanks It doesn't regulate it. You do not want it to regulate the water leaving the tank. It just removes everything you pump up from the sump. That's why they're called overflows. It's a bit easier to see how it works with an in tank one. When the pump is off the water is at the edge of overflowing down the pipe into the sump. You turn the pump on it increases the height of the water in the tank and it overflows down the pipe. It's all regulated by the return pump. Quote Link to comment Share on other sites More sharing options...
SamH Posted March 28, 2010 Author Report Share Posted March 28, 2010 Thanks for the explanation Ira If the bottom of the U tube was lower than the end in the tank, it'd create a siphon right? Quote Link to comment Share on other sites More sharing options...
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