How much flow is needed during a power outage?

[mattvd]

Hello all,
I have a 220 gallon saltwater tank with a 40 gallon sump.

How do I know how much flow I need in the event of a power outage?

I see most reefers have battery backups for their power heads to run 8-10 hours off of.

I have 2 MP40s in my tank. Do I need battery backups for both? Just for one? Should I get two battery backups so that one power head can run longer?

Im confused as to how much flow I need at once versus having a little bit of flow last longer. Which is better in a power outage?

 

[davidcalgary29]

The battery backup should allow you two run two vortech powerheads simultaneously. BRS states that two MP10s will run for 36 hours off of a fully-charged unit; if and (I would check with Ecotech first) you can run two MP40s off of the same unit, I would assume that your maximal run time would be lessened. I'd certainly shoot for two powerheads with your size of tank.

After reading all of the Power Outage Horror Stories on this site I decided to simply install a power transfer switch in my house and buy a generator. I'm certainly glad I did this, as the power's gone out mysteriously on multiple occasions this year for most of the day. I have a battery backup, but I'm glad that I didn't need to use it.

EDIT: I just checked the manual, and, yes, it appears you can run two MP40s off of the same unit. Ecotech states you can run one MP40 for 36 hours off a charged unit, and 18 hours with two.

 

[EeyoreIsMySpiritAnimal]

Hello all,
I have a 220 gallon saltwater tank with a 40 gallon sump.

How do I know how much flow I need in the event of a power outage?

I see most reefers have battery backups for their power heads to run 8-10 hours off of.

I have 2 MP40s in my tank. Do I need battery backups for both? Just for one? Should I get two battery backups so that one power head can run longer?

Im confused as to how much flow I need at once versus having a little bit of flow last longer. Which is better in a power outage?

On my 90 gallon, I have an Icecap battery backup on one of my Jebao powerheads. This powerhead angles up and agitates the surface. The main reason flow is so important when the power goes out is to maintain a good oxygen level so the fish don't suffocate.

If you can set up more backup power and run more pumps, that's even better, but at minimum, make sure you're getting surface agitation.

Edit: I agree 100% that a generator is the only longer term solution... The battery backup is more for short outages and/or when I'm not home.

 

[WVNed]

I went 5 days on return pumps only for flow. In the end with all 1200 watts of heaters running the temps fell because the house became that cold. Then the power came on and saved me.
We have a whole house generator now.

It has already run 89 hours.

09/09/2022 01:29 PM EDT

Running due to Utility Loss

 

[Gatorpa]

My go to back up in a pinch is a 500g/hr bilge pump run off a car battery. That was for a 120 gallon for a week due to a hurricane. No generator. It would last about 18 hours before needing recharge.
I imagine a deep cycle marine battery would last longer and I’m sure there are many better solutions no with the improvements in battery back ups.

 

[mattvd]

Thanks all for the responses. More specifically my question is what is the most efficient way to run a tank during a power outage?

Is it two power heads at once? Is it only one power head but for longer? What if the power head is located in the middle of my tank and doesn’t break the surface tension of my water too much? Would it be a bad idea to buy a single mp10 power head that is just pointed up at the surface purely for surface agitation during a power outage?

Looking to find the most efficient setup for a power outage that will maximize my battery backups. Thanks!

 

[Reefer Matt]

My opinion: I would suggest using one powerhead on a battery backup, and a battery operated air pump with an air stone. If a generator is not an option for you, then this will keep the water aerated and moving.
Depending on your location and time of year when an outage happens, you may want to consider how to maintain temperature as well.

 

[Malcontent]

Looking to find the most efficient setup for a power outage that will maximize my battery backups. Thanks!

I did some informal testing a year or two ago and air stones were ~7X more efficient than wavemakers in terms of oxygen levels per watt. A pump mounted on the bottom of the tank aimed upwards was the worst performer by far and basically did nothing.

 

[LeannaBanana]

I also have battery backup for one pump, and then one battery-powered air stone available per tank. I don't know if that's _right_, but that's what I have and it's kept everyone alive for minor power outages. The longest we've gone since moving into our house was just under 24 hours w/o power. We also have a generator (not whole house) that we could toggle with the fridge/freezer if we absolutely had to in a bigger outage.

 

[mattvd]

I did some informal testing a year or two ago and air stones were ~7X more efficient than wavemakers in terms of oxygen levels per watt. A pump mounted on the bottom of the tank aimed upwards was the worst performer by far and basically did nothing.

This is really interesting! Do you have more details on the test and setup? Do you always have the airstone in the tank even when the power is on? What battery backup and air stone are you using?

 

[mattvd]

My opinion: I would suggest using one powerhead on a battery backup, and a battery operated air pump with an air stone. If a generator is not an option for you, then this will keep the water aerated and moving.
Depending on your location and time of year when an outage happens, you may want to consider how to maintain temperature as well.

Thanks! Sounds like this is the direction I am going to go in to maximize the amount of battery backups that I have. Do you have a recommendation on the battery backup for the air stone? Also trying to think of how to place the air stone in the main tank without it being an eyesore, because obviously I can’t place it in the sump if the power were out and my return pump wasn’t operating.

 

[Reefer Matt]

Thanks! Sounds like this is the direction I am going to go in to maximize the amount of battery backups that I have. Do you have a recommendation on the battery backup for the air stone? Also trying to think of how to place the air stone in the main tank without it being an eyesore, because obviously I can’t place it in the sump if the power were out and my return pump wasn’t operating.

You're welcome. I see a few on Amazon, I searched "portable aquarium air pump" and I would consider function over appearance in an emergency such as a power outage. You can leave the air pump put away when not in use. Good luck!

 

[HB AL]

I would only worry about proper oxygenation of the water during an emergency and keeping the temp stable. The rest is gravy.

 

[mattvd]

I would only worry about proper oxygenation of the water during an emergency and keeping the temp stable. The rest is gravy.

Agreed, but my question is what is proper oxygenation during a power outage? Is it a return pump? Is it 1 power head? Is it 2 power heads? Is it 1 power head for longer or is it 2 power heads for a short period of time? What if the power heads are in the middle of the tank and the top line of my water doesn't really move up and down like a wave? Is that still fine? Is it an air stone right next to one power head so the power head can circulate that airstone more?

I understand the need for proper oxygenation but I don't know how to achieve it efficiently with my setup of 2 MP40s and 2 battery backups in a 220 gallon main tank.

 

[Malcontent]

This is really interesting! Do you have more details on the test and setup? Do you always have the airstone in the tank even when the power is on? What battery backup and air stone are you using?

Yes, the air stone is always on in my freshwater tank. Oxygen levels just aren't high enough without it despite having a wet/dry filter.

The wet/dry stayed on the whole time and I simply added/removed/turned on/off the wavemakers, air stone, and pump and waited for the dissolved oxygen levels to reach a new steady state. Power consumption was measured by one of those Kill-A-Watt things but were pretty much in line with what the manufacturers specified.

Surface agitation is much less efficient than bubble aeration which is why wastewater treatment plants switched decades ago. Up to 70% of their operating costs are for aeration. There are tons of studies that found that bubble aeration gives you several times the oxygen transfer per energy consumed.

My backup power is a 1000W pure sine wave inverter attached to my hybrid car's battery (located conveniently in the trunk). I had an outage for several hours this spring and ran my tanks normally off of it. I also powered two freezers in the basement.

 

[Dburr1014]

Food for thought,
My 75 gallon has gone 5 hours with nothing before I could get to the tank.
1 tang
2 clowns
And 3 other small fish.
It has gone multiple times 3+ hours.
Edit: Now I have a small computer backup with the MP40 plugged into it. That goes almost 2 hours by itself.

 

[GobyGuy]

you’re going to need atleast 1 for sure

no credible knowledge on fish o2 needs of that capacity lol following to see

 

[jDoSe]

Use air pumps. Oxygenation is what you need. They are also cost effective to get multiple ones and you can just swap out the batteries.

Flow doesn’t hurt, but multiple airpumps or a single airpump with split lines will do a lot.

It’ll look ugly with all tubes everywhere and bubbles in the tank; but it’s not about looking good, it’s about keeping things alive.

 

[mattvd]

Use air pumps. Oxygenation is what you need. They are also cost effective to get multiple ones and you can just swap out the batteries.

Flow doesn’t hurt, but multiple airpumps or a single airpump with split lines will do a lot.

It’ll look ugly with all tubes everywhere and bubbles in the tank; but it’s not about looking good, it’s about keeping things alive.

Agreed, but my thought with the air pumps, that typically can work with flow. But if there is no flow in the tank, what good are the air pumps? The air bubbles will go directly to the top and not circulate in the tank. I suppose if the fish started to realize that they aren't suffocating when they're next to the air pump they might naturally move around it - but don't you need both the air pump to create the oxygenation, and also the powerhead to circulate that throughout the tank?

So what would the ideal setup be? An airpump on battery backup that is right next to a powerhead that is also on battery backup? That way we can actually circulate the oxygen throughout the water?

 

[jDoSe]

Agreed, but my thought with the air pumps, that typically can work with flow. But if there is no flow in the tank, what good are the air pumps? The air bubbles will go directly to the top and not circulate in the tank. I suppose if the fish started to realize that they aren't suffocating when they're next to the air pump they might naturally move around it - but don't you need both the air pump to create the oxygenation, and also the powerhead to circulate that throughout the tank?

So what would the ideal setup be? An airpump on battery backup that is right next to a powerhead that is also on battery backup? That way we can actually circulate the oxygen throughout the water?

Ideal setup is multiple redundant generators you test monthly.

The air bubbles rise to the top, but still create some water flow. Obviously not as much as a horizontal powerhead, but usually enough. Look for videos of airpumps/airstones online with no hob filter to get an idea of how much.

Test it out; buy a cheap air pump, turn everything off then see if you think it will suffice. You can test with multiple pumps, multiple lines, and different diffusers.
For a tank over 200g you are going to want more than one pump to make sure it reaches the whole tank.