Preventing Display Tank Overflow

[NotoriousENG]

Hi Everyone,

I have a 20 long freshwater planted tank that is set up more like a reef tank with a drilled overflow and a 10-gallon sump. At some point in the future, I am planning to be away from home for a week or two and starting to think about how to floodproof my tank.

I have the sump sized so that it doesn't flood when I lose power (put to test this week during a power outage). I also have a prefilter on my siphon drain and have been running the water level in my overflow box low enough so the emergency drain stays fully dry. What I am most worried about is the teeth of the weir box getting clogged by leaves from the plants. If that happens the main tank would quickly flood. So my question is are there any good solutions for this or am I looking at having to DIY a level sensor (float, optical, etc) to a relay to cut the pump power when the water level gets too high?

 

[T-J]

Can you post a pic of the overflow?
In my tank, the top of the overflow is open, and it's below the top of the tank, so even if all the teeth were blocked, the water would simply flow over the top of the overflow box.
I'm guessing yours is setup the same way.

 

[NotoriousENG]

Sure, this first picture is how I usually run the overflow with a screen over the weir teeth to avoid sucking up baby shrimp. I would take this screen off if I were traveling since it clogs too quickly.

This next one shows how the overflow sits in the tank. I had to mount it flush to the rim to get the water level within the black trim. In retrospect mounting it so high probably wasn't smart. I did sand the top of the weir down so water can flow over the top.

If I plug the weir teeth, the water does spill over the top of the weir box without flooding the tank. However, it gets scarily close to the top of the tank as shown below.

When it spills over the top the weir also eats any floating debris putting my drains at a higher risk of clogging. For a long trip, I would banish all my floating plants to the sump since they are prime drain cloggers.

I could sand the top of the weir box down some more. I would probably get a lot of plastic dust in the tank but if I did a big water change and vacuumed the substrate I would think it would be okay. I suppose I could try to get a neighbor to come over every day or two to pick leaves out of the weir teeth.

 

[SDK]

Do you not have your pump isolated in a separate pump chamber in your sump?

If not, you should order something like the Fiji Cube 10G DIY sump kit and isolate the pump. Then if the drain clogs, there is only that small amount of water in the pump chamber that can be pumped in, not the full volume in the sump.

Properly set up, you should be able to fully plug/block your drain or cut your power without a flood. I also use a smaller container for my ATO so if it malfunctions stuck on, it still wont overflow my tank.

There is almost no such thing as building in too many failsafe's here, as something will eventually go wrong where water is involved...

 

[NotoriousENG]

Currently, I have my sump setup using a baffle-free design that uses foam sheets instead of dividers to minimize surface ripple (less of the Co2 I inject gets lost to the room). I also do not use an ATO at this time since it's less important for freshwater. I just top manually with distilled water when I remember so no risk of flooding the sump/tank due to ATO malfunction.

I did do the math before and if I remember correctly I would need a pump chamber of less than a gallon to avoid flooding the tank which would be hard to fit my pump in. I will redo my math to see what size of the chamber I would be dealing with.

 

[blaxsun]

What if you placed a larger mesh basket over the overflow, such that it extends out several inches past the sides of the overflow?

 

[SDK]

I've kept a fair amount of high tech planted tanks with no filtration or nutrient export at all other than trimming the plants. If that was my tank I would just shut the sump completely off for the week or two you are away. You don't really need it anyway.

You are braver than me combining that sump with plants, which were a constant source of leaf related clogs. Hence me ditching the filters altogether for a small powerhead to circulate the water.

 

[hanslanda]

Use an siphon tube directly in the main tank, and run it directly to the back of the overflow box. You could run the tube as low in the tank as you want and it would be a good backup if the main tank height got to high. When you get home, rip it out. Of course the risk is sucking up fish, but you are attempting to specifically circumvent straining the water so I'm thinking you're okay with that.

This is how external overflow boxes work.

 

[eggplantparrot]

What if you placed a larger mesh basket over the overflow, such that it extends out several inches past the sides of the overflow?

yea, since you're not going to be at home, you can make some sort of a much larger prefilter that just hangs around the overflow drain. could be ugly as hell but who cares.

 

[NotoriousENG]

There's a lot of other good ideas that have been mentioned so far, I really appreciate the help everyone!

I've kept a fair amount of high tech planted tanks with no filtration or nutrient export at all other than trimming the plants. If that was my tank I would just shut the sump completely off for the week or two you are away. You don't really need it anyway.

You are braver than me combining that sump with plants, which were a constant source of leaf related clogs. Hence me ditching the filters altogether for a small powerhead to circulate the water.

I'm not sure braver is the word I would use, dumber might be a better fit or maybe bullheaded.

Shutting the sump down is a good idea. Even before you mentioned that was my backup plan if I can't get anything else to work. If I were to do it, I would probably put a HOB on the display tank while I was gone since I already have one and have media for it in the sump just in case. Shutting down the sump would mean I can't inject CO2 via the cerges reactor but I could use a needle wheel powerhead as a temporary injection method. Lastly, so I don't kill off the bacteria in the sumps biofilter I was thinking I would move a few fish from the main tank down to the large open chamber in the sump. Then I would just reroute the pump line to feed the far side of the sump for circulation and turn the pump power way down. Splitting the fish between the main tank and the sump has the added benefit of splitting the bioload which would hopefully prevent an ammonia spike due to taking the sump offline.

Use an siphon tube directly in the main tank, and run it directly to the back of the overflow box. You could run the tube as low in the tank as you want and it would be a good backup if the main tank height got to high. When you get home, rip it out. Of course the risk is sucking up fish, but you are attempting to specifically circumvent straining the water so I'm thinking you're okay with that.

This is how external overflow boxes work.

This is an interesting idea! If I go this route I would probably put some sponge over the tube to prevent sucking up all of my shrimp. If a few shrimp end up down in the sump it's not a huge deal, but netting them all out of the sump and moving them back to the main tank would be tedious. The only possible issue I see with this idea is that the depth of the tube in the tank would be very important. If it's too deep and the tank loses power it could overflow the sump.

What if you placed a larger mesh basket over the overflow, such that it extends out several inches past the sides of the overflow?

I am currently working on something similar to this to test out. My idea is to have a leaf guard/surface dam of sorts 3D printed. What I am envisioning is a three-sided square that has slots to hang off of the front of the weir box. Water would flow in through the open bottom. The three sides of the square would extend about a half-inch above and below the water line to prevent any floating debris from reaching the teeth.

The downside of this design is that I would lose surface skimming but this probably isn't a big deal for a week or so if I aim my outflows at the surface to make sure there's enough ripple to prevent protein film from cutting off gas exchange.

 

[Uncle99]

From the looks, wouldn’t the water just overflow the overflow box?
Have you tested what would happen by taping those slits up to simulate a complete plug?
We do this test on all setups including pulling the power, and restarting.

 

[NotoriousENG]

From the looks, wouldn’t the water just overflow the overflow box?
Have you tested what would happen by taping those slits up to simulate a complete plug?
We do this test on all setups including pulling the power, and restarting.

It does overflow the top, but the water level gets extremely close to the top of the tank. In post 3 I have some pictures of water level with the weir teeth fully plugged with plastic.

I am thinking that no matter what option I end up choosing I will probably sand the top of the overflow down some more. I already sanded it down some when I first installed it since I had to mount it very high on the tank to get the water level under the trim, but I should have sanded more off.

 

[NotoriousENG]

Got the prototype leaf guard/dam I described earlier in it seems to be working as it should. I can't tank all the credit for it since I only came up with the initial idea and rough design and a local 3D print shop figured out the details and printed it. I will try this prototype for a while and see how it goes. I'm already thinking a V2 version with slots on the front face to keep some level of surface skimming might be beneficial.

Any comments or suggestions are appreciated!