View Full Version : Tips to avoid leaks or flood in FOWLR tank

11-12-2009, 04:49 PM
Hi, I am new to the hobby and I am planning to setup a FOWLR system at some point but still in the planning phase.

One thing that came out from some of the research I made was that some people get leaks or flood from either
their sumps or fishtanks do to different reasons (Poweroutage, siphon from main tank, not enough room in sump etc...)

I was wondering if there was a way to build the system to avoid having flood or leaks as much as possible.

For instance, does a pre drilled tank with a sump still could flood ? I tried to do research and could not find
anything to provide tips on what to do to totally avoid floods.

At some point I was even looking at something like the Red Sea Max 250 as everything is in the same tank and therefore would remove the flooding potential, but would not be suited for bigger fishes and is more a reef tank than a FOWLR.

Could you guys direct me on how this could be achieved.


11-12-2009, 05:09 PM
In my case, I have a 180G DT with a 105G refuge, the display has 2 overflows on either side with Standpipes. What this means is that if the return pump fails, only a certain amount of water will flow out of the main tank into my refuge. With the refuge, it isn't full, maybe half, so it has more than enough room for this display tank water in that case.

Also make sure to match your return pumps with your flow, or have valves so you can adjust this. When I first got my tank, I regretted it, the first night I had water flowing over the top of the main tank on my head. NOT FUN!!! I couldn't get things matched up.

Over the next few days all was good, but one night I couldn't sleep, when I went out to check the tank, it was just starting to again flow over the top of the display. I ran, swearing and opening all valves wide open....

After that I looked into durso standpipes. I made some put them in my overflows and I can say they have been the best creation I have done to this thing. All my valves (downward and upward flow) are wide open, so no more worries about overflows, and they also quited down the noise to nothing on the overflows.

If buying a used tank, maybe have it resealed, if buying new, buy from a reputable LFS and brand. If custom made, again have it made by someone that knows what they are doing.

I hope this helps some.

Tom R
11-12-2009, 05:22 PM
One of the main reasons you have a sump is to help eliminate floods.

Your sump has to be big enough to be able to absorb the excess water in the system when the power goes off.
The amount of water to be absorbed is the excess water in the water level above the overflow and the water in the lines to and from the sump. The tank can also syphon down to the level of the inlet nozzle you can help offset the amount of syphon water by having a small hole in the nozzle that will allow air into the nozzle line to break the syphon. You have check the system from time to time to ensure that the sump is still able to absorb the excess water without overflowing into a flooded room. Both the nozzle and the air hole have a tendency to clog with algae over a period of time.

Tom R

new but handy
11-13-2009, 01:24 AM
keep the aquarium outside:mrgreen:

11-13-2009, 03:16 AM
keep the aquarium outside:mrgreen:

I was just gonna say ...dont get into fish....:mrgreen:... I could tell you about the time I first filled up my 110g to leak test it with the garden hose(I was by myself that day)....lets just say that, a garden hose under pressure coming loose from where you had it wedged, when you go outside to turn it off is a baaaaaad thing:redface::lol:

new but handy
11-13-2009, 03:29 AM
I have flooded my basement suite twice, both times I was working out of town.
I have a very patient girlfriend.

11-13-2009, 02:28 PM
Thanks for the replies guys, much appreciated.

By the way you guys have very nice setups.

We had a flood two years ago in the middle of July during a thunderstorm and our sump pump in the basement decided to stop working that day. My wife and I were both at work and 4 inches of water across the basement cost nearly 35K to the insurance to repair and change a lot of the furnitures. That's why I want to try to avoid any more floods as much as possible.
I am sure there are lot of people that have had aquariums for years and never had floods.
I guess I just want prevent rather than fix things that could have been avoided right from the start.


11-14-2009, 10:03 PM
I woke up to about 40G of water on my floor this morning :)

RO/DI water though...left it on overnight and forgot. I still haven't set up a float valve, been putting it off but I will be doing that this weekend now!

That doesn't help much but I think if your in the hobby long enough, you end up with some sort of flood, big or small. Try to do a bunch of research and do your best to keep the water in the tanks. Over the years, none of my displays have ever flooded. Actually only ever RO water.

11-15-2009, 04:03 AM
Ro/DI water tip:
Buy the 4 gallon blue rectangular pail at walmart($5)- it has a small spout on one end. Put the pail next to the sink. Pt a 18" 2x4 flat on the counter under the pail on far side from sink. When you forget about your RO/DI (which I do all the time) it will just overflow into the sink since the pail is on a slight angle with the spout facing the sink. Negative of this is you only do 4 gallons at a time and then pour into bigger pails- positive is that you don't destroy your house when you forget about it. My 2 cents.

golf nut
11-15-2009, 04:49 AM
It really isn't difficult, you just have to understand it.

Water enters the tank from the sump at a known gph, it needs to be drained, if you select the correct size return pump and the correct size drain the will never be any noise and never be a flood, you will not need a Durso nor will you need siphon holes if the return pipes go just under the surface.

If you decide to use a smaller drain hole than is required then you will get noise, caused by the drain turning into a siphon then losing siphon due to the flow increase, and repeating it's elf, then you read about Dursos and spend money buying something to fix the problem that you created in the first place by not using a bulkhead big enough to handle the flow.

Feeds from the sump need to go just slightly under the water, the depth they penetrate is a simple math formulea to tell you how much reserve space you need in the sump.

Fill the tank add water to the sump, turn on the pump once the tank and oveflow box are full then turn off all the power, the tank will drain to the sump as will excess in the overflow box and any back siphon from the return lines from the sump.

Now fill the sump to a level that you feel comfortable having it at, ie 2" below the surface, turn on the return pump and wait until the water is now moving through the system , you will see the sump level fall to its operating level, draw a line at that point and never add water to any more than that level when the system is running.

I will put money on it that almost any tank if installed with a 2" drain with a 1" return from the sump with almost any pump up to 1800gph will be silent, safe and have a zero chance of flooding.

new but handy
11-15-2009, 04:58 AM
having 2- 2" drains, = peace of mind
having 1" return = safty
having a pump at less than 1800gph = easy

forgeting to turn off your ro. = The only thing anyone can gauruntee
come on everyone has done it

golf nut
11-15-2009, 05:08 AM
forgeting to turn off your ro. = The only thing anyone can gauruntee
come on everyone has done it

Considering you typically waste 2/3 of the water you use to make ro/di you may as well run the overflow from the storage unit to the same drain, that way there is no flood just a high water bill.

11-15-2009, 08:30 PM
Those are all great tips to consider, thanks guys.

I am not too worried about the RO water as I have a full bathroom in the basement with a bathtub where I will be making the RO water in and if the water overflows from the bucket, it won't be a big deal as the container will be sitting in the tub.

As I can see, if the design is planned well, the flood occurrence cant be very well be under control. I have read numerous thread where floods could of been avoided.