Siphon overflows

[MOT]

Hi everybody, I am a new member and am interested what yall have to say about siphon overflows. I have a forty gallon acrylic tank currently holding my minireef. I want to connect it to one of the extra glass tanks i have laying around as a refugium. I have an extra 29g, 50g, and 55g. obviously I want to avoid a flood at all costs. The CPR overflows utilize a small pump which theoreticly sucks any accumulated airbubbles from a small hole at the top of the U-tube. This mechanism will supposedly restart the siphon in case of a power outage also. Sounds pretty fool proof to me. As far as drilling acylic tanks... is there an optimal place to drill the hole? I was thinking the bottom might be best because there is no bowing on the bottom because it is fully supported. Is there a difference in sound for either method? I have read some things about siphon overflows being noisy? If anyone has any advice, words of wisdom or reassurance I would greatly appreciate it. I have lost many many many hours of sleep thinking about it. Thanks Tom

[dandy7200]

Tom, drilling is the way to go on this without a doubt. Acrylic is a fairly soft plastic and a dull hole saw cuts right through the 1/4" material your tank is likely made from. Siphons are indeed loud and far from fool proof. If you decide to absolutely go that direction there is a good reliable one on the market by lifereef.com but it's very pricey. OK so back to drilling cause thats what you really want to do anyways Drill high up on the tank about 2" from the edge of the hole to the top and corner. If a leak happens to form you only want the top portion of the tank to end up on the floor not the entire tank right :wink:

[jason the filter freak]

I agree with drilling, deff the way to go

[YBeNormal]

Oh come on now guys... Both of my tanks have siphon overflows and neither of them have ever been a problem. OK, OK. There was that time that a snail climbed into the u-tube, actually several times, and bubbles almost never gather in the u-tubes and reduce flow. Nope, almost never (at least not while I'm home to take care of it and to mop up the flood).

 

Seriously though, siphons work great when everything is set up and maintained correctly but they will fail eventually. You can use siphon overflows and avoid floods by carefully setting the water level in your tank and in your sump to make sure that a lost siphon will not cause the tank to overflow but a drilled tank is definitely the better choice. If my tanks were acrylic they would have been drilled long ago.

[bbyatv]

I have a glass tank and so drilling is not really a good Idea for me.

 

As a result, I have an overflow with a U-Tube.

 

My tank sits on hardwood floors so I am very paranoid about water spilling out of the tank.

 

I have gone to extremes to keep this from happening.

 

I have redundant float switches installed in the overflow box that cut power to the return pump. These switches make it so that if during a power outage I lose my siphon and then the power comes back on, the water from the sump does not end up overflowing the main tank and on the floor. I have two switches in off chance a snail has one stuck closed the other will cut the power.

 

At the top of the u-tube, I have drilled a hole and connected a piece of air line from it to a venturi on a pump that is in the tank. This venturi sucks up any bubbles that might form in the u-tube.

 

I have also set up a bubble trap in the overflow box to reduce the amount of bubbles that make it into the u-tube.

 

In the return lines from the sump to the main tank, I have drilled small holes very near the surface of the water so if power cuts off a siphon will not take out the first 2 inches of water from the main tank back down into the sump and overflow it.

 

Here is a picture of the overflow box where all of the work is done.

 

If you want to set something like this up, let me know and I can give you any details you might need.

 

Oh ya, my tank is nearly silent. No noise from the overflow at all. Creative plumbing fixes the issue.

 

 

Bruce

Hi everybody, I am a new member and am interested what yall have to say about siphon overflows. I have a forty gallon acrylic tank currently holding my minireef. I want to connect it to one of the extra glass tanks i have laying around as a refugium. I have an extra 29g, 50g, and 55g. obviously I want to avoid a flood at all costs. The CPR overflows utilize a small pump which theoreticly sucks any accumulated airbubbles from a small hole at the top of the U-tube. This mechanism will supposedly restart the siphon in case of a power outage also. Sounds pretty fool proof to me. As far as drilling acylic tanks... is there an optimal place to drill the hole? I was thinking the bottom might be best because there is no bowing on the bottom because it is fully supported. Is there a difference in sound for either method? I have read some things about siphon overflows being noisy? If anyone has any advice, words of wisdom or reassurance I would greatly appreciate it. I have lost many many many hours of sleep thinking about it. Thanks Tom

Edited March 13, 2007 by bbyatv

[MOT]

Hey guys thanks for the advice. I think I will drill the tank although setting up a siphon overflow with float switches keeping it in check also seems a viable solution. The tank is only forty gallons though and I would like to simplify it as much as possible so there won't be too many things cluttering the space like an overflow; one of the many reasons I am adding a sump/refugium. So anyone ever drill an acrylic tank? I have read a few things. They say that you need to keep the acrylic cool or it will crack, also never to stop the drill while it is in the acrylic or it will fuse to it. I suppose I am going to have empty my tank while I do this...a good opportunity to buff the acrylic I would imagine; anybody know anything about buffing acrylic? I did use a hole saw to try and cut a hole in a 3 gallon eclipse (1/8 inch acrylic) and I see some small cracks, so I am not very confident though the 1/4 inch acrylic on my forty will likely be easier. Methinks a sharper saw would help, but dandy 7200 you say dull? por que? Oh yeah, and does silicone bond to acrylic? that I might seal the bulkhead with something more than the O-ring? Does anyone know of a glass shop that might cut this hole for me with diamand bit saw if I bring them an empty tank? I am pretty scared to drill the tank myself. I would just man up and buy a reef ready tank, but I am just a poor college student who unknowingly stumbled into a rediculously addictive(and incredibly rewarding) hobby, I'm sure you know what I mean. Tom

[Almon]

I have glass tanks and was never comfortable with drilling them, although I believe that having drilled tanks would be much more convenient. You probably should drill your tank, but have one of the WAMAS members come over and help you. It sounds like Dandy (and others) is an expert on the subject.

 

With that said, I have 3 glass tanks on the same system and use siphon overflows for all of them. The key to never losing the siphon is to have plenty of water flow. I use two overflows on the main 220g tank going to the sump below. Until recently, I had a gravity siphon from the 220g to a 40g that was about 1' away which then emptied through another siphon overflow back into the sump. That was 3 overflows handling approximately 250 gph each, all being pumped back up to the main tank via one Little Giant pump.

 

I have recently added a 55g refugium to the setup. The 55g and 40g tanks are back to back allowing me to use a homemade siphon overflow from a customized specimen container and a U tube that flows into a hangon Aquaclear filter that is used to add water flow and current to the 40g. The gravity siphon from the 220g now flows into the 55g refugium, which overflows into the 40g, which overflows into the sump, to be pumped back up to the 220g. Below is a picture of the 3 tanks and a closeup of the homemade overflow.

 

 

 

During a power outage, all overflow siphons remain intact, but the gravity siphon will draw air once the water level of the 220g has fallen. However, with a sufficient loop in the gravity siphon tube, the gravity siphon is restarted when power is restored as the water level in the 220g increases from the excess water that has drained into the sump.

 

I use a APC450 Battery Backup for the main pump so I always have water flowing through all of my tanks due to the siphon overflows.

[rooroo]

On my old 65 I had two siphon overflows handling about 300 gph each. I NEVER had a flood with them, but I was very vigilant about watching for bubbles and algae buildup in the u-tubes. When I had enough flow and the water level set properly, I didn't even have to watch for bubble buildup. But it was a habit that I always checked my tank and the overflows every morning and evening to ensure they were functioning properly. I still have that habit of looking at my tank twice a day to ensure everything is functioning properly. Rather than drill the old 65 which was glass and of an unknown manufacturer, I got a new reef ready tank. My mom took the old 65 and drilled it for a frag tank, so it was drillable but I wasn't willing to do it.

 

Anyway, if you have acrylic, its very easy to drill (I've watched). You should def go that route because I would frequently get up in the middle of the night to check on my tanks overflows when I had them. Good luck!