How to prevent a flood

[mets17127]

It could lead to a huge expense, and there are many different tricks. Since each person has their own ways, lets share them to make a comprehensive list.
I have a 90 gal undrilled with a HOB overflowbox into megaflow sump with a quietone 4000 return.

To detect a leak of any sort, I got a few flood alarms from HD. They are $10, next to the sump pumps, and sound an alarm when they are sitting in even a little bit of water. What's even cooler, you can leave the base in one spot and run the actual alarm to another area (via a long wire) so you can hear it better. I put black plastic sheeting under my sump, and put one alarm next to in (in my stand) and one on the floor behind the stand.

For DT flood (syphon break, overflow clog, etc..):
large u-tubes that always stay submerged
turn tank side of tubes inward (toward middle of box) to avoid air bubble accumulation
Ultralife float switch in DT to shut off return if level gets too high
Keep teeth on inner box clean
Keep sump level low
Keep DT level on low side
Can also- put an aqualifter on the U-tubes to keep the air out
put a float switch in the sump to turn off when water gets too low

For sump flood (reverse syphon in return line with power outage):
check valve on return line
drill a few holes in return just just below DT water level to break syphon (only one hole might get blocked by a snail)
Keep the sump water low

I have an idea that if the inner box for the overflow falls into the tank, then it will continue syphoning until the u-tube is above the water line, meaning a lot of water! The only fix there is drilling the connection plate and putting a screw through so it can't slide off. Low sump water may also prevent a huge flood.

Thats all I have done, or thought to do...anyone else?

 

[fppf]

Flood risk is all about system design.
Flood alarms are great for telling you that you screwed up.

There are a few things in your system design that you can do to avert any chance of a flood baring a container breach. IE the tank leaks or your sump cracks.

First, check valves are great, until they get gunked up with growth and other stuff in our systems. They will leak, no doubt about it. So I skip check valves all together. Instead of check valves just make your sump large enough to handle all of the back flow when the pump is off. This way there is no way to overflow the sump.

Then there is the what if my return line is blocked. Design your sump so that when the system is operating the return pump is just slightly below water level. Then make sure the water level in your tank is a little lower then the top. This way you can totally block the return, the water in the tank will rise close to the rim but then the pump sucks air. This way there is no way to overflow the tank. You may damage your pump, but in most cases the back flow when the pump looses prime keeps it lubricated enough.

The last piece is your top off water. DO NOT hook your RO system directly to the tank with a valve. Your asking for something to stick and overflow your tank. This is the one and ONLY way I ever made a flood. So now I have a small top off reservoir. It holds enough top off water for about a week. And I can add all that water at once and still not overflow the tank in the case of a return failure. Then once a week I top off the reservoir.

With these 3 design goals you should be able to reduce the flood risk to near zero. I have not had any release of water in my systems in the last 6 years. I only started 7 years ago.

 

[RyanTurner]

My advice would be to drill the tank and plumb it. Ditch the HOB overflow. From what I hear, they are a flood waiting to happen.

 

[mets17127]

true, a drilled tank offers less flood risk and can be placed closer to the wall, but seeing as MANY people have HOB overflows, lets try to be more helpful in either setup

 

[fppf]

My advice would be to drill the tank and plumb it. Ditch the HOB overflow. From what I hear, they are a flood waiting to happen.

I have had my HOB from the very beginning and never had an issue. Again, the key is to have a proper design. To small and the water will back up into the tank with the slightest restriction. To large and there wont be enough water velocity to keep bubbles from forming.

Also, if you follow the design strategy of having only enough water left in the sump for the pump to operate. If you loose the HOB no big deal, the tank fills to the rim and the pump does not have anymore water to put in there.

Drilling the tank has its risks as well. You just put seals at the bottom of the tank. If they fail you could loose ALL the water in the tank.

To help reduce the risk of loosing the siphon on the HOB you can place a power head in the tank and run a tube from the venturi fitting on the power head into the top of the HOB. This will suck out any air bubbles that try to form.

 

[petemattersen]

im putting at 1/4 inch bulkhead in the top of my ro reservoir today to prevent flooding, that way if the float valve on the ro doesnt work it just drains off into my washing machine drain

 

[andyrm66]

Dont leave your RODI making water and good to bed, to wake up the next moring wondering why it sounds like rain in the house, all over your newly laid floor. Twice.

 

[TheFishMan65]

FYI those flood alarms from HD aren't perfect. I got one for my RO (in case I didn't hear the timer). I did not miss the timer, but the hose fell out of the bucket. The alarm failed. The reason was (I think) a tile floor. It is slippery enough (I guess) that the water did not form a deep enough pool. So it you use one test it periodically to to make sure the battery is good. I am going to try setting it on a paper towel - just in case some one else needs an idea.

 

[fppf]

Actually there was nothing wrong with the alarm or the floor.

It's the water.

RODI is up near 18 meg ohms in resistance. So high the alarms wont trigger.
So don't bother trying to use it with pure RODI water. Saltwater however is very conductive.

 

[TheFishMan65]

I would agree, but my RO/DI water read 0 TDS, but it still triggers my alarm. Do you think my RO/DI system is faulty?

 

[jcolley]

im putting at 1/4 inch bulkhead in the top of my ro reservoir today to prevent flooding, that way if the float valve on the ro doesnt work it just drains off into my washing machine drain

Bingo...

Design the system failsafe so you don't have to be there when the alarm goes off.

I'm using a Beananimal to provide safety for the tank to the sump then a 1.5" bulkhead near the top of the sump with a 90 elbow downturned as an emergency drain. I plumbed mine as part of the water change system that dumps to my household DWV sewer, but you could easily do the same with a piece of rigid tubing or PVC out an exterior wall.

And for backup, use a float switch and a relay to kill power to the return pump if you want, then you would at least maintain recirc on power heads or CL. I can't think of a scenario off the top of my head where they could be the source of the problem...anyone else?

 

[fppf]

I would agree, but my RO/DI water read 0 TDS, but it still triggers my alarm. Do you think my RO/DI system is faulty?

It does not take much to add enough free ions to the water and drop the resistance. Your filters are most likely fine.

 

[TheFishMan65]

That is what I figured, I checked with a second meter and get a TDS reading of 1. The other thing I realized was that unless we have a really clean floors there is probably enough dust and such to drop the resistance. I expect even the soap residue from cleaning would to it.

 

[rfalvey89]

My advice would be to drill the tank and plumb it. Ditch the HOB overflow. From what I hear, they are a flood waiting to happen.

...yeah , get rid of that thing. I had a 60 gal hex with a HOB overflow. It would constantly be a PITA .With the noises at all hours of the day/night and you have to "siphon" to start -on top of the fact that it did get clogged and overflowed the tank onto a powerstrip which burnt my carpet and wall. NEVER is a long time , but I will assure you that I will NEVER have a HOB overflow on a SW tank again. Get it drilled or buy a nice aquarium, whether it's 10 or 100 gallons I think alot of reefers would agree that saltwater is the LAST thing you want on your carpet/floors....:fun5:

 

[ruiny]

I have had several floods from overflowing skimmers.
So now all skimmers are in sump or the cup is overflowed back into the sump.

I have also had sumps overflow from there not being enough room for backwash with pump off. What can happen is that alge grows on the overflow grating increasing the water in the display a bit, this worked out to 10 gallons an inch in my last tank. But it isn't water tight so the water will still drain slowly. Add that to a basement sump and you have about 20 gallons of water to drain back. The autotopoff still keeps the sump at the same level, result is more water in the system than you planed on = flood.
So make sure that the sump can hold all the drain back water x2.

 

[Ron Reefman]

Flexible PVC shower pan liner under the entire bottom of the stand. So the sump, refugium, frag tank, reactors and external pumps are all inside. The liner even has a bulkhead and drain line going thru the wall and out of the house!

 

[obaptista]

Build your overflow and pipe to handle a clog. A snail or fish finds it's way into an overflow, drilled or HOB and your tank will overflow. So, dual pipes in an overflow box or dual overflows or large diameter pipe. Had a hawkfish partially clog a factory reef-ready overflow. Luckily it was only partial and the tank trickled over.

 

[reefkeeper78]

I have an auto shut off for my ro/di system that is tee'd into the feed line of the first filter. I have flooded my entire basement with over 2000 pictures filled with water. the feed line blew out of the filter and sprayed water to the ceiling which rained down onto open totes filled with years and years worth of pictures. It only ran like this for about 2 1/2 hours but it was enough to put almost an inch of water into the basemnt. After that the $40 for the unit to kill the water supply was a no brainer. It is so sensitve that the moisture accumulation on the floor will set it off when its super humid outside. So far its save my butt twice.

As for the tank itself, there are water on floor sensors for some of the contollers on the market. If set up right, they will shut down the pumps in the event of an overflow. Best to have redundancy in your flood prevention but a sensor can save alot of water from hitting the floor as well. My basement sump can pump a sick amount of water in a very short time, I have forgotten to turn a valve back on when changing out a sock filter and iin a matter of a minute, it overflowed the tank. with the sensor on the floor, yes you get water on the floor but the controller is faster than I am when it comes to running downstairs to turn off a pump.

Probally the best prevention to water on the floor though is to take up a different hobby altogehter..... but I like the challenge to much

 

[wildman926]

Modified Pump Stopper kit from Aquahub with dual float switches in the event the overflow sticks, if that is possible with mesh screens and bio ball.

Coralvue Waste container with built in overflow switch.

Pics -

 

[dan3949]

I would also say that redundancy is key to good flood prevention. Never rely on a single float switch for a top-off system. Also I use a float switch wired to a Reef Keeper controller and a separate float switch wired to a independent relay that provides power to my ATO pump. Thus, either of the float switch and/or systems could fail and the other would prevent a flood. Also, use of a simple mechanical float valve (often used in RO/DI systems) is a inexpensive additional level of defense when used where the ATO adds water to the sump (if the water level goes too high, the float shuts-off all flow into the sump).

I also use float switches in the main tank to trip the return pump if the level gets too high.

I also strongly agree with use of leak detector/solenoid shut-off valve for a RO/DI system that is automated. I have had the plastic hose on my system split and spray water (luckily it is in my garage so no damage resulted). I have my RO/DI connected to a stroage tank with a DIY latching controller (a high a low float switch and a DPDT relay). Also, I included an emergency drain that is plumbed outside if the water ever gets stuck in the on position.