How to Prevent an Overflow
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Category: Specialized Discussion
Forum Name: Equipment
Forum Description: This is the place to ask question about reef equipment.
URL: http://www.utahreefs.com/forum/forum_posts.asp?TID=20841
Printed Date: July 20 2026 at 7:30pm
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Topic: How to Prevent an Overflow
Posted By: acromacromonti
Subject: How to Prevent an Overflow
Date Posted: October 01 2007 at 2:06pm
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So I have a 75 gallon and soon a 32 gallon project and was wondering if anybody has any idea on how to prevent a overflow for when power outages happen which lately seems to be alot, I am running overflow boxes on both and when power goes out it keeps sucking water into the sump and I am going to have a heart attack if I keep worrying about the tank all day everyday I am gone. Any feedback would be greatly appreciated, thanks so much guys.
Chad
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Replies:
Posted By: ReefBones
Date Posted: October 01 2007 at 2:25pm
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if its coming from your returns, Put your returns closer to the water surface .. this will only allow the tank to drain so much .. you can also drill a small hole in your return line .. if you are using Locline you drill it right where it screws into your PVC fitting Make sure that you point the hole you drilled down so it dose not squirt the water out of the tank .. this will cause the siphon to suck air and break the siphon .. if your overflow box is still draining water after the pump is off and your sump is over flowing .. drop the water level in the sump so there is room for the water coming from the tank.
If your over flows are looking siphon when the power comes back on and your tank is over flowing .. the best way is just to drill the tank .. OR I have seen overflows with a little nipple on them that you connect to a power head that (in theory) will suck the air from the overflow box and restart the siphon ... ------------- 140 gallon Reef 65 gallon Reef 55 gallon Aggressive www.thesalttank.com 801-865-6074 "encourage other divers and sea enthusiasts to take nothing but pictures and leave nothing but bubbles" |
Posted By: Mark Peterson
Date Posted: October 01 2007 at 5:35pm
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Feel free to email me and I'll send you the document that I wrote specifically about this. mailto:[email protected] - [email protected] ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member 
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Posted By: BHYDE
Date Posted: October 01 2007 at 6:01pm
| Drilling a hole works well until it gets covered with salt creep or a snail or whatever. I always use a check valve on my return lines. I think it slows my overall flow back to the tank a little, but its better than having a huge mess if the power goes out while I'm gone. I don't understand how its your overflow box causing the flooding when the power is out. If the return pump is off with the power, how is it your overflow box keeps filling with water in order to siphon down to the sump? |
Posted By: pa_reptileman_4
Date Posted: October 02 2007 at 12:16am
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i have my return pipes completly out of the water so that way no reverse siphon can start if power goes out. i also have just enough water in my tank to keep the overflow going and if the water stops going into my main tank my over flow only drops the water about 1/4-1/2 inch which still leaves about 4-6 inches of room in my sump.... i test it alot just to make sure. ------------- pitiful guppy tank. shane |
Posted By: ReefBones
Date Posted: October 02 2007 at 9:24am
Ya thats kinda in my monthly maintenance schedule .. to make sure they are cleaned out ... but again on my system my returns are close enough to the surface that evan if it did clog up it will not drain enough to overflow my sump .. ------------- 140 gallon Reef 65 gallon Reef 55 gallon Aggressive www.thesalttank.com 801-865-6074 "encourage other divers and sea enthusiasts to take nothing but pictures and leave nothing but bubbles" |
BHYDE wrote:Posted By: Mike Savage
Date Posted: October 02 2007 at 10:53am
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but again on my system my returns are close enough to the surface that evan if it did clog up it will not drain enough to overflow my sump ..
A clogged hole in a durso will drain less water and overflow the tank. Try it. Put your finger over the air hole and watch the tank level rise. The only way the tank won't overflow is if the pump area of the sump goes dry first.
Mike -------------  |
Posted By: GARFVolunteer
Date Posted: October 02 2007 at 11:20am
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Calculating the sump size and configuration can be very critical. I like to have as large of sump as possible. However, in my opinion, compartmentalizing the sump is the key to success. You will need to calculate the amount of water that the display tank can hold if the overflow fails. This is done by measuring the distance from the display tank's normal water level surface to the rim of the tank. Let's call this measured value the height (H). All measurements will be in inches. Measure the length (L) and the width (W) of the tank. The calculation to determine the volume in gallons it can hold above the overflow is H x L x W / 231. Let's use my tank as an example for this calculation. I have 1.5 inches from the normal water level in my tank to the top rim of the tank. My tank is 48" long and 24" wide with 1/2" glass so the calculation is 1.5 x 47 x 23 equals approximately 7 gallons (I round down just to be safe). So when I made my sump, I made the volume of the last compartment from the pump intake to the rim of the compartment a little less than 7 gallons. Now if my overflow fails, I can not flood the living room. Using this method has saved me more than once. The next thing that we need to do is determine the overall size of the sump. During a power outage water will drain from the display tank to the sump. This water will come from two sources. The first source is the overflow. The water in the tank will drain down to the top of the internal overflow box. The second source is from the return pump line. This is the easiest source to miss since many of us will forget that the water will siphon fr om the tank to the sump from this line though the pump. One trick I like to do is to drill a 1/8" hole in the return line just below the water surface. This hole will allow siphon to break when the water level drop below the hole. The calculation to determine the extra volume needed during a power outage is similar to the one we used before. Measure the distance in inches from the normal water level to the level the water will drop to when the return pump turns off. Let's call this measurement height (H). We will use the length and width measurement we used before. The calculation to determine the additional sump water volume needed above normal water levels is H x L x W / 231. Using my tank as an example, the water level drops 3/4" when the return pump turns off. So the minimum additional volume needed in the sump is 3/4" x 47" x 24" = 3.5 gallons. To be on the safe side always round up when doing this calculation. My current sump is a 30 gallon breeder tank that measures 12" x 36" x 18". The last compartment holds 6.5 gallons and
the maximum water level in the sump is 8". This leaves me with ~11 gallons (4" x 36" x 18" / 231 ) of volume remaining for any extra overflow. I have a 150 gallon Tall Perfecto Reef Ready tank. I have noticed that algae likes to build up on the overflow. This slowly raises the tank level over time. For monthly preventive maintenance, I clean the algae out of the overflow teeth. If I did not, there could be an overflow and the lovely and gracious Monica would be disappointed with me...
Thanks,
Scott ------------- President Idaho Marine Aquarium Society A fair and biased reef hobbyist "How do you make poor people rich by making rich people poor" Rush Limbaugh on Obama taxes |
Posted By: ReefBones
Date Posted: October 02 2007 at 11:38am
Mike,
Not talking about the Durso .. I am talking about the siphon break in the return line a small hole is drilled into the locline just before entering the PVC fitting ...
It has also been my experience that a clogged hole in the durso will cause a "Flushing" effect issues most common with durso`s ... if the hole is too big than you can have over flow issues ... when I cover the hole in my durso on my frag tank I get the loud "flushing"effect breaking the siphon but as soon as the water rises above the elbow on the durso it quickly starts a siphon again sucking the water out of the over flow area ...
It all depends on how much water you are pumping from your sump .. the more water you are pumping the smaller the hole in the durso needs to be.
------------- 140 gallon Reef 65 gallon Reef 55 gallon Aggressive www.thesalttank.com 801-865-6074 "encourage other divers and sea enthusiasts to take nothing but pictures and leave nothing but bubbles" |
Posted By: jfinch
Date Posted: October 02 2007 at 4:02pm
Just the opposite, Mike. Without an air hole a durso will just be a syphon and will cycle your overflow box level up and down making a flushing sound at the bottom of the cycle. A hole too big can sometimes cause overflows (but not due to power outages). It just seriously decreases the capacity of the Durso.
edit: What Steve said. I didn't see his post when I posted.... ------------- Jon https://www.youtube.com/channel/UC6y_EzjI_ljbIwf2n5uNzTw" rel="nofollow - What I've been doing... |
Posted By: bbeck4x4
Date Posted: October 02 2007 at 4:52pm
don't ever rely on a check valve in aquarium systems, they will fail, they are not designed to overcome the algae and the coral buildup that will occur inside the pipes, light getting in there or not, also a wayward snail (dead or alive) could be stuck inside the hinge area, any leakage from it will still cause a siphon and drain your tank, best bet is to use it (if you are going to)in addition to the above mentioned methods. ------------- Family Portraits /Google trusted Photographer for Google Maps for Businesses |
Posted By: Mark Peterson
Date Posted: October 02 2007 at 5:47pm
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Check Valves have been the demise of many floors and carpets. It's not if, but when they get stuck open. ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member
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Posted By: BHYDE
Date Posted: October 02 2007 at 6:12pm
| I set up my first tank with a sump about five years ago and have never had a problem with a check valve since that time. Maybe I'm just lucky. I do run a flexible hose brush through it once in a while. |
Posted By: Mike Savage
Date Posted: October 02 2007 at 9:39pm
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When the air hole in my durso would close in with salt creep the level of the tank would keep raising to the top. Maybe it didn't get high enough to flush? Mike ------------- |
Posted By: jfinch
Date Posted: October 03 2007 at 9:26am
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The level in your overflow box is really the only level that should cycle (although on some very taxed dursos the tank level might rise just bit as the overflow box overfills). Your duro elbow should be about 3-6 inches below the overflow box weir (i.e. the level in your overflow box should be about 3-6" below the tank level). Without a breather hole, the durso siphons, pulling the level down to the bottom of the under turned elbow, then breaks and the level in the overflow box rises until it gets high enough to start a siphon again. Properly sized overflow box and durso will keep all this cycling in the overflow box and not in the tank.
Mike, maybe your durso is too high in your overflow box? ------------- Jon https://www.youtube.com/channel/UC6y_EzjI_ljbIwf2n5uNzTw" rel="nofollow - What I've been doing... |
Posted By: ReefBones
Date Posted: October 03 2007 at 9:39am
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Mike like jon stated .. your elbow may be to high in the over flow box .. it can and usually dose rise a inch or 2 above the elbow (pending on your pump) before a full siphon is created again. if your elbow is only a few inches down from the top of the water than I can see where your tank can over flow ... ALL of my tanks have the durso elbow mid way up the tank .. so their is no chance of a over flow if the siphon is broken .. this also aids in gas exchange as the water has to fall half way down the tank ... there are a lot of tanks that I have seen where they keep the water level in there over flow box at water level with the tank or just under ... this is a bad idea IMO ... again IMO you should set your overflow at 2 to 3 inches minimum below the water line in your tank ------------- 140 gallon Reef 65 gallon Reef 55 gallon Aggressive www.thesalttank.com 801-865-6074 "encourage other divers and sea enthusiasts to take nothing but pictures and leave nothing but bubbles" |
Posted By: Mike Savage
Date Posted: October 03 2007 at 2:21pm
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Thanks Jon and Steve!
I learn things on this site every day. I'm sure that my durso was too high for two years! I no longer have that tank. Early on I had problems with it making noise and I had a LFS that does a lot of tank maintenance come to my house and adjust it properly and that is how they adjusted it!
Mike ------------- |
Posted By: Jake Pehrson
Date Posted: October 03 2007 at 4:14pm
Thanks Mark. That is what I was just going to post.
I think that you should always have more then one defense against problems. Holes will plug and check valves WILL fail.
I like to use check valves for extra security, but I also like to setup your return so that it can stop the syphon by itself (holes, strategically paced returns, etc.) ------------- Jake Pehrson Murray http://coralplanet.com" rel="nofollow - coralplanet.com http://utahbeeranch.com" rel="nofollow - :) |
Posted By: rdbrown
Date Posted: October 30 2007 at 9:22pm
| The easiest solution that I have found and done is goto Lowes and put an anti-siphon valve inline on the return line. They cost about 4 or 5 dollars and allow water to flow only one way. |
Posted By: jessedidthis
Date Posted: October 31 2007 at 12:27pm
careful when selecting the check valve and be sure it doesn't have any metal. Some have a metal spring inside and not only is this NOT GOOD for your tank, they tend to not close when water is going the other way. The best check valves are made with rubber and gravity and close them. |
Posted By: jessedidthis
Date Posted: October 31 2007 at 12:40pm
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90g tank, 29g sump. I use a dorso standpipe in an All-Glass 90g with drilled bottom and overflow box. This makes it so that the water only drains below the overflow box and then breaks the siphon. The siphon always starts back up when water overflows into the box. I have one return low into the water and the other more shallow in the water. This makes it so that when the water drops below the return, the siphon is broken. It was a lot cheaper to just move my return than to spend $30 on a check valve from the aquarium. When i turn off my pump, the water starts to flow into the sump. I marked where it stops and i have about 10g remaining. |
Posted By: Bryguy514
Date Posted: October 31 2007 at 10:56pm
| Ugghhh check valves terrible memories |