Desktop fan for temperature control

[Archon]

As the title says, what do you think on using a desktop fan on a temp controller to create an air current around a 5 gallon tank in order to lower its temperature? 

I know that most will advise for CPU fans hitting the water surface in order to achieve cooling from evaporation but has anyone tried a desktop fan next to the tank? Would this help reduce the water’s temperature?

[teenyreef]

I used a small desktop fan once when my AC was out. It was much stronger that my computer fan and worked great. It's just a question of whether you like the look or not 🙂

 

[Archon]

Well, there is already a mess of cables next to the tank so adding a fan would not bother me that much. 😆

Just a clarification, did you position the fan so that it would blow air towards the water surface or just towards the glass/around the tank?

The second case is what I’m after as I have a glass cover which also supports the light and would like to avoid messing with the cover.

[teenyreef]

2 hours ago, Archon said:

Well, there is already a mess of cables next to the tank so adding a fan would not bother me that much. 😆

Just a clarification, did you position the fan so that it would blow air towards the water surface or just towards the glass/around the tank?

The second case is what I’m after as I have a glass cover which also supports the light and would like to avoid messing with the cover.

Ah, I see. Mine was pointing right at/across the water. I don't think pointing at the glass would do much, but I haven't tried that. The fan blowing across the water works well because it encourages evaporation which cools the water (I think...high school physics was a long time ago).

[Archon]

OK I might give it a try then with a floor fan that I already have and see if it makes any difference. 

[mcarroll]

What's the story with needing the fan in the first place?   Folks generally don't need cooling as long as they're lighting the tank with LED's.

[teenyreef]

40 minutes ago, mcarroll said:

What's the story with needing the fan in the first place?   Folks generally don't need cooling as long as they're lighting the tank with LED's.

My 30g tank with a sump never needs cooling. But both of my AIO's (10g and 40g) tend to overheat by two to five degrees in the summer time, even though I have LED's and keep my air conditioning reasonably cool. I think the increased surface area and moving water from the sump cools things off more. In the AIO's, the combination of lights and pumps just seems to be a little too much.

 

I have a Apex-controlled computer fan that goes on and off if the temps get too high. But even then, I see my temp going up one or two degrees on hot afternoons.

[mcarroll]

4 hours ago, teenyreef said:

My 30g tank with a sump never needs cooling.

Same room as the other tanks?

 

4 hours ago, teenyreef said:

But both of my AIO's (10g and 40g) tend to overheat by two to five degrees in the summer time, even though I have LED's and keep my air conditioning reasonably cool.

What temperature is normal and what temp do you consider to be "overheating"?

 

Have you logged the night time temperature and peak daytime temperature?  What's the maximum day/night swing you get in the summer?

 

Also, is the tank taking direct sunlight in the summer?  Not sure why else the season would matter too much on a closed tank unless you vary the temp on your HVAC system seasonally.  (Do you?)

 

(I'm getting somewhere with the questions...I promise!)

[NoOneLikesADryTang]

6 hours ago, mcarroll said:

What's the story with needing the fan in the first place?   Folks generally don't need cooling as long as they're lighting the tank with LED's.

This most certainly isn’t true. In Phoenix, cooling your tank is a necessity. We’ve got fans over our nanos, to keep them under 81, and we ended up hooking up the chiller today on our 80 gallon tank, once it got to 83.5 degrees (all though, this tank does have T5’s on it). While it may not be necessary in Virginia, cooling your tank is a real issues for some people. 

[mcarroll]

3 hours ago, NoOneLikesADryTang said:

This most certainly isn’t true. In Phoenix, cooling your tank is a necessity. We’ve got fans over our nanos, to keep them under 81, and we ended up hooking up the chiller today on our 80 gallon tank, once it got to 83.5 degrees (all though, this tank does have T5’s on it). While it may not be necessary in Virginia, cooling your tank is a real issues for some people. 

Usually makes sense to ask questions before giving answers....so more questions!  😁

 

What makes you feel like 80 or 83 is "too high"?

 

 

What temp does your 80 Gal get to if you don't run a chiller on it?

 

What temp do you keep your house?

 

[Archon]

13 hours ago, mcarroll said:

What's the story with needing the fan in the first place?   Folks generally don't need cooling as long as they're lighting the tank with LED's.

As stated before, living in a hot climate makes cooling down the tank a necessity. Edit: same as having a 5G tank.

What are the parameters you would consider? so that I can give you more details.

Edited April 28, 2020 by Archon

[mcarroll]

16 hours ago, Archon said:

What are the parameters you would consider? so that I can give you more details.

Most folks have HVAC and keep the the house around 72ºF.  

 

Tank heating and cooling guidelines are generally based on this assumption.  

 

I didn't hear anyone claim they weren't HVAC'ing their house.  If there is HVAC, then I can't see why extra cooling would be needed for the tank.

 

We're also assuming (until it's stated otherwise) that we're talking about tropical animals in the tank.  If you're keeping something different (ie from cooler water), again I didn't hear anyone claim it.

 

So, is the house kept at around 72ºF?  If not then maybe you'll have to apply some cooling directly to the tank.  But maybe you won't.

 

Unless the tank is hitting close to 90ºF, or you're keeping cooler-water livestock vs tropical, there is no reason to assume there's going to be a problem.  Most folks seem to worry when temps get over 78ºF, but I'm not sure why.  Tropical areas are often around 86ºF or even higher in some instances.

 

If the concern isn't peak temperature, but day/night temperature swings, then I might suggest more heating to limit the drop at night rather than more cooling to limit the temp during the day.

 

Cooling is very expensive vs heating....either in terms of $$ for the gear or in terms of more gear taking up more space on/around the tank.

 

BTW, what do you have for lights?  

Can you post a full tank pick that shows the lid/everything?  

If possible, how many watts of gear are operating in the tank, including the lights (which aren't technically IN the tank....but count them anyway).

[NoOneLikesADryTang]

You’re assuming a lot be assuming to OP keeps his home at 72 degrees. He said he lived in a hot climate. In Phoenix, it’s rare for anyone to keep their house that cool. It’s common place in the afternoons for people to keep their house at 82 or 83 degrees when the electricity is really, really expensive. I don’t know anyone here who keeps their home at 72. 
 

By your logic, why would a heater be needed in reef tanks for the winter time? We want these things for stability (the number one rule in reef keeping). 
 

To answer the OP’s original question, I don’t know, but I would doubt it. I would definitely be curious if you did it, to see the results. I think the fan needs to hit the water surface to get evaporative cooling. 
 

I use these, and they work well on my ADA 60P’s. All though, they are a bit noisy when they’re running, and the definitely take away from the look of the tanks. 
 

LONDAFISH Aquarium Chillers Aquarium Fan Fish Tank Cooling Fan Marine 2 Fan https://www.amazon.com/dp/B07FCJGZ4H/ref=cm_sw_r_cp_api_i_WGsQEbZM9N6P0

 

[mcarroll]

1 hour ago, NoOneLikesADryTang said:

You’re assuming a lot be assuming to OP keeps his home at 72 degrees.

It seems like you might be a little too eager to disagree in this case:

• You dodged all my questions.
• You're making the assumption that for some reason we all know about building management practices specific to Phoenix.
• You're assuming that the OP keeps his house just like you keep yours.

Assumptions all over the place!!!  😉

 

I think you'll get a kick out of this Google search where every link above the fold says something like 72ºF: household+temperature+in+phoenix

😉

 

But I'm sure there are plenty of exceptions.....I'm not trying to assume anything, just showing that normal is normal, even where you are....yet I'm still asking questions vs making assumptions.

 

And there's a reason for 72...not just cuz I say so.  LOL

 

Check out the Wikipedia page for "room temperature" so you know what I'm talking about:

https://en.wikipedia.org/wiki/Room_temperature  👍

 

(In a nutshell: It's based on skin temperature, which is based on body temperature.  It's not based on the city you're in.  Some science journals use rounded values for easy math and will consider 20, 25 or 30ºC (68ºF, 77ºF and 86ºF) as an arbitrary "room temperature" for calculations.  This is not the same as what we're talking about...we're talking HVAC.)

 

So much for assumptions.  🦖

 

Still waiting on the OP's second round of responses before I get into recommendations, but I'll get back to the original question.  I promise! 👌

 

 

[Archon]

Thanks for the responses so far. The temperature controller is currently set at 27C/~81F. Recently, with the weather change, the temperature started fluctuating from 27C/81F during the night, to 29C/~84F. The outside temperatures will keep rising so I posted this question in order to have time to prepare for the summer.

As we are used to the high temperatures where I live, it is not so usual to constantly operate HVAC systems. To give you an idea, I started using the AC in my bedroom just in the past 4-5 years. Also, operating such systems 24/7 is quite unaffordable especially when people are absent from their homes during the biggest part of the day.

 

Now for the tank gear, the light I have is the Aqua Knight (30W), a Korallia nano 1600L/420GPH (4.5W) and a small internal filter for the filter floss (1-2W).

 

It will be kind of embarrassing to post a FTS but I will upload one in a while.

[Archon]

OK, here are a couple of pictures showing the tank and the glass lid that supports the light. Excuse me for the mess around the tank but it sits on the kitchen counter and I don’t have enough space to hide cables etc.