Sea breezes at home: Have you ever used fans to impact flow?

[Peace River]

Sea breezes at home: Have you ever used fans to impact flow?

When we think about fans and reef tanks, usually we are talking about cooling or about drying water on the floor (yet again!). These are both real issues – I can’t tell you how many times I have had water on the floor (RODI overflow anyone?) that needed to be dried up with towels and a fan. Additionally, tanks on the top end of the recommended temperature range (or above) have also cause many to add cooling fans. But have you ever thought about using fans to impact flow? In addition to cooling, creating water turbulence at the surface of the water can also provide other benefits such as oxygenation, moving surface water, and more. If you have ever used fans to create flow (either intentionally or not), please tell us about your experience in the related discussion thread.

Photo by @Epic Aquaculture; March 2024 Reef of the Month


This QOTD is sponsored by: www.deltecdirectusa.com

“With dozens of protein skimmers, calcium reactors, media reactors and kalkwasser stirrers in operation, Deltec USA can speak from experience and help you with all your Deltec needs. Live customer support and a large inventory of products rounds out our mission to provide the best possible Deltec experience.”

 

[Randy Holmes-Farley]

Only flow of air. lol

 

[X-37B]

First I have heard of this. I would think to get water movement from air you would create alot of salt spray.
Not something I would want in a home system.
Interested to see if anyone else is doing this at home.

 

[Epic Aquaculture]

Yes we do! The pic in the OP is the top of our DT. The two orange fans you see are small industrial floor fans and can be found on Amazon. We installed these for cooling, obviously, but the side benefit is that because the flow is so focused it actually creates a current at the top of the water column when they are on. Because they are on a controller and turn on at a temp set point, this current ends up being at random times throughout the day so it just adds more random flow to the tank. It has worked great for the initial intended purpose of cooling, and the side benefit of more random flow has been a great added bonus!

 

[Epic Aquaculture]

First I have heard of this. I would think to get water movement from air you would create alot of salt spray.
Not something I would want in a home system.
Interested to see if anyone else is doing this at home.

The pic in the OP is our DT. It actually does not create any salt spray at all on this setup. On a shorter tank that might not be the case.

 

[X-37B]

Nice! Spray might not be the right word.
For cooling they work great. Mine was always in the sump.
We get alot of salt from our open tops. It is seen as rust on any exposed metal surface in the room.
Air across the surface will just create more even if it cant be seen.
Great idea for large or commetcial systems
Anyone running this at home?

 

[vlangel]

Nope, I never even would have thought of this for flow, although I have used fans for cooling.

 

[Gumbies R Us]

Not me, I honestly have never thought about using fans to impact flow

 

[Jay Hemdal]

Sea breezes at home: Have you ever used fans to impact flow?

When we think about fans and reef tanks, usually we are talking about cooling or about drying water on the floor (yet again!). These are both real issues – I can’t tell you how many times I have had water on the floor (RODI overflow anyone?) that needed to be dried up with towels and a fan. Additionally, tanks on the top end of the recommended temperature range (or above) have also cause many to add cooling fans. But have you ever thought about using fans to impact flow? In addition to cooling, creating water turbulence at the surface of the water can also provide other benefits such as oxygenation, moving surface water, and more. If you have ever used fans to create flow (either intentionally or not), please tell us about your experience in the related discussion thread.

Photo by @Epic Aquaculture; March 2024 Reef of the Month


This QOTD is sponsored by: www.deltecdirectusa.com

“With dozens of protein skimmers, calcium reactors, media reactors and kalkwasser stirrers in operation, Deltec USA can speak from experience and help you with all your Deltec needs. Live customer support and a large inventory of products rounds out our mission to provide the best possible Deltec experience.”

I actually used to use this method in a public aquarium reef exhibit and wrote about it in my Advanced Marine book. Here is the text from that (current production in bold below):

Differential air pressure
This method of water current production has not been mentioned as having applications for home aquarists, yet it is the primary force of water motion in nature. In the world’s oceans, the pressure of air moving over the surface of the water produces an ever-changing variety of waves and water currents. The same principle, on a much smaller scale, can have the same affect in home aquariums. This phenomenon was first identified because in some aquariums, (especially with complicated reef systems) waste heat from the life support equipment such as lights and pumps attached to an aquarium raises the water temperature to levels unhealthy for the aquarium inhabitants. One solution to this problem, a refrigeration/chiller system, is often prohibitively expensive both in initial cost as well as in operation. When the desired water temperature is less than 5 to 7 degrees Fahrenheit below the ambient room temperature, aquarists have successfully relied on the evaporative cooling effect produced by moving air across the surface of the aquarium with a fan. This airflow will also generate substantial water currents. However, the aquarist must either turn the fan on and off as needed, or set the thermostat on the aquarium’s heater at a higher set point to avoid over-cooling the water (and then accepting the higher energy cost incurred while periodically running the heater and fan simultaneously). It may be common knowledge to some; but by using a standard water chiller thermostat, the fan can be controlled more precisely, often holding the aquarium’s temperature to within one or two degrees of the target temperature.
In one example, when a 1500 gallon reef exhibit was test-filled, it was discovered that the light coming in through the skylights, the additional metal halide lighting and the large number of pumps all contributed to raising the aquarium’s water temperature to 83 degrees, six degrees above the target temperature of 77 degrees. A 20” - 1/6th hp fan with airflow of 7500 CFM, was attached above the tank, directing air horizontally down the length of the aquarium, with the lower edge of the fan about 6” above the surface of the water. This lowered the water temperature to within a scope of 73 to 77 degrees. However, this wide temperature range was not acceptable, and was caused by the variations in the evaporation rate resulting from changing humidity levels and daily fluctuations in the room’s air temperature. By plugging the fan into a Goldline chiller controller (model SP-33) it was possible to reduce this temperature range to one degree, between 76 and 77 degrees. The controller would now operate the fan when the aquarium water warmed up in the heat of the afternoon, and then be turned off in the early evening when the water was cooler.
Two additional benefits became apparent. While the fan was running, substantial water currents were generated and a series of light-refracting wavelets were produced. The flow of the water current was calculated to be 2700 gallons per hour by timing a drift bottle driven down the length of the tank by the current produced by the fan. It should be noted that this was a theoretical maximum, measured with all of the aquarium’s pumps turned off – in normal operation; the affects of some of this wind-driven current would be cancelled out by the opposing currents produced by the various oscillating pumps. In regards to the surface wavelets produced, they were noted to have some affect on the light regime within the aquarium. Using a submersible light meter situated 12” below the water’s surface; a still-water reading of 375 footcandles was taken. With the fan on, the wavelets refracted the light, causing the light level to shift rapidly between 330 and 370 footcandles. The overall effect of these glitter lines (or ripple lines) is esthetically pleasing, and the reduction in average light transmission into the aquarium had no apparent affect on the animals (as this system was already well lit with metal halide lamps). With the meter’s probe held horizontally, the still water reading was 50 footcandles. With the fan on, the level then varied between 50 and 75 footcandles, actually increasing the amount of reflected light traveling horizontally in the aquarium. This may have some minor benefit for getting more light to the base of corals otherwise shaded from light only coming down directly from above.
The only drawbacks to this method seem to be the greater need for make-up water to replace that lost due to increased evaporation, and potentially shortened fan life due to its operation in a salt-laden atmosphere.

 

[Epic Aquaculture]

Nice! Spray might not be the right word.
For cooling they work great. Mine was always in the sump.
We get alot of salt from our open tops. It is seen as rust on any exposed metal surface in the room.
Air across the surface will just create more even if it cant be seen.
Great idea for large or commetcial systems
Anyone running this at home?

Only freshwater evaporates leaving the salt behind, so it is no more than we would have if the fans were not on the tank. This system is located in my home. Salt spray or salt evaporation/rusting is not a problem at all.

 

[XMASTER]

Man your evaporation must be crazy. And those fans looks like the fans they use to dry floors

 

[shakacuz]

o my purpose i use fans is to push hot/warm air away from the surface of the water to help keep temps from rising too much during the warmer weather. don’t see the point of doing it for any other reason

 

[Surf City Corals]

Sea breezes at home: Have you ever used fans to impact flow?

When we think about fans and reef tanks, usually we are talking about cooling or about drying water on the floor (yet again!). These are both real issues – I can’t tell you how many times I have had water on the floor (RODI overflow anyone?) that needed to be dried up with towels and a fan. Additionally, tanks on the top end of the recommended temperature range (or above) have also cause many to add cooling fans. But have you ever thought about using fans to impact flow? In addition to cooling, creating water turbulence at the surface of the water can also provide other benefits such as oxygenation, moving surface water, and more. If you have ever used fans to create flow (either intentionally or not), please tell us about your experience in the related discussion thread.

Photo by @Epic Aquaculture; March 2024 Reef of the Month


This QOTD is sponsored by: www.deltecdirectusa.com

“With dozens of protein skimmers, calcium reactors, media reactors and kalkwasser stirrers in operation, Deltec USA can speak from experience and help you with all your Deltec needs. Live customer support and a large inventory of products rounds out our mission to provide the best possible Deltec experience.”

YES! Thank you for this discussion. I have had this exact same question. I have 3 mixed reef nano tanks and getting appropriate flow is difficult with limited real estate and wide array of flow needs. I haven't tried it yet but in my mind theoretically the fan above the water offers a modest amount of additional flow increased oxygenation from surface break, turbulence and more naturalistic habitat in my opinion where fish have access to these benefits. From what I've seen at LFS and online, the fan above water adds a very wide spread of medium flow which is highly beneficial to a mixed reef especially in a mixed reef nano where wide spread flow can be difficult to achieve. I will be trying a fan for flow in my nanos soon.

 

[Epic Aquaculture]



Man your evaporation must be crazy. And those fans looks like the fans they use to dry floors

It is LOL. This system evaporates about 10 gallons per day. We actually want it to do that as we dose just under 10 gallons a day of kalk.

 

[Borat]

Hellou, how ken I put dis in my fishs' home? I em concerned dat it might scare my pets!

 

[GlassMunky]

Only freshwater evaporates leaving the salt behind, so it is no more than we would have if the fans were not on the tank. This system is located in my home. Salt spray or salt evaporation/rusting is not a problem at all.

thats not really like in a persons living room thou. you have a whole fish room hidden behind the tank, just like all public aquariums and aquaculture facilities. i would HIGHLY doubt that the average home aquarist with a single tank in the living room or wherever would ever actually do this. and if someone does, they are the odd man out, its not something even half of people will do.
you pretty much HAVE to have the giant hood over top the tank to even have this as an option which most people dont.

 

[GlassMunky]

Only freshwater evaporates leaving the salt behind, so it is no more than we would have if the fans were not on the tank. This system is located in my home. Salt spray or salt evaporation/rusting is not a problem at all.

its a beautiful system, dont get me wrong. i just dont this is something that can be compared to the AVERAGE HOBBYIST.

 

[kenchilada]

Here's my fans I use for producing light-refracting wavelets in my tank.

 

[X-37B]

Only freshwater evaporates leaving the salt behind, so it is no more than we would have if the fans were not on the tank. This system is located in my home. Salt spray or salt evaporation/rusting is not a problem at all.

I know its not from evaporation as you are correct.
That system appears to have heavy surface agitation.
If you have heavy surface agitation you are creating droplets of water that contain salt and everything else in your water. You may not see it but its there. I know many people running heavy surface agitation, im one of them, that get rust on exposed metal in the room.
Best example is all the rusting fans seen on led fixtures where the fan is on the top of the fixture.
Anyway, glad its working for you, and keep an eye on any exposed metal over time.
Enjoy your reef as your system looks incredable.