Help, thermostat needed!

andysgirl8800

andysgirl8800

Blenny Badlands
Alright, here's the issue...I'm having a little trouble stabilizing my tank temperature. I do not run a heater on my tank at all, since all my periferal equipment keeps the tank water plenty warm enough. In fact, I must run the fan in my hood most of the time. This is where the problem is.

I have a retro fit fan built into my hood. I believe it used to be a heavy duty computer fan perhaps. Anyway, it's wired to a regular 2 prong plug and plugged into my 110 outlet. GREAT little fan, nice and quiet. Anyway...without lights on and the fan off, my tank will stay between 80.2 and 81.7 degrees. Although I know that's a fine temp to be at, I really prefer it around 78.4-79.1 degrees.

However, once my lights come on, (obviously) the temp starts to rise. This is when I turn the fan on, slightly before the lights are about to start up. The fan will stay on until about 2 hours after the lights go out. I am currently manually turning on or off the fan, based on tank temp. If I forget to turn it off overnight, the temp is at about 74.7 by morning. Since temp in the house can fluctuate, I can't rely on timers to control the fan. This is not an ideal solution.

I would really really like to find a thermostat type of setup, under $50, or a DIY solution to control the fan on or off depending on temperature. This means that the unit would need a saltwater-safe temp probe, an outlet to plug my fan into, and a manual or digital temperature range.

I was looking at this one:

[ame=http://www.amazon.com/Hydrofarm-MTPRTC-Digital-Thermostat-Heat/dp/B000NZZG3S/ref=sr_1_2?ie=UTF8&s=home-garden&qid=1269533918&sr=8-2]Amazon.com: Hydrofarm MTPRTC Digital Thermostat For Heat Mats: Home & Garden[/ame]

But I can't determine if it would work for a fan? Does this thing work simply by turning on or off a device based on temp? Does it have to be a heat mat?
 
AG, that's a really high base temp, imo... mine with no heater goes down to like 73. How warm do you keep your house? do you have a lot of surface area for water to evaporate from? How far from the top of the tank to your lights?
 
Amanda,
the lights are a little more than 12" above the water. The house is kept at 68 during the day and 65 at night. I do have a lot of surface area for evaporation. Here are 2 things contributing to the higher heat:

1) the tank sits in a room at the front of the house, which faces south. this means that the front of the house receives direct sunlight all day long and the room gets pretty warm...but not like a sauna.

2) the magnetic ballasts for the lights are stored in the stand, which means their heat warms up the sump which is also in my stand. I do not open the doors in the stand to ventilate because I have kids and cats.
 
ok, is the back part of your stand open? Mine is... I'd get some big ol fans, one on each end.... point one into the stand and one out of the stand to get better air flow there. If it's not open, I'd be cutting holes on either side of the stand, and put fans in there. you can even make it pretty with vent covers from Lowe's/home depot.

Personally, I also put blackout curtains in the windows near my tank, to reduce the amount of sunlight heating up my tank. it's not even summer yet, so your tank will definitely be better off if you eliminate as many sources of heat as you can now, rather than waiting til it ends up with a catastrophic temp spike (like happened to me last summer....)
 
Thanks Amanda! I do have vents to open on the canopy, I do have blackout curtains on the windows, and my fan is awesome!! Unless I can put up clouds in front of my house everyday, I can't keep the sun off the front of the house, so even with curtains and fans, the room heats up. *L* I just need to work out a better controller for it. If I leave it on all the time, the tank drops too low overnight. If I forget to turn it on, it gets too hot. I guess what I am saying is, I can control the temp just fine....with constant human attention. I'd really rather automate it.
 
personally I'd leave the fan on and just buy a heater and stick it in the overflow. IMO it's difficult to balance the heat without having a heater. Like cc said, the more intricate solution is to get a controller like an RKL, but those aren't terribly cheap.
 
Years ago I had a friend who lived on a military base and had free utillities. It would be 100+ degrees outside and he would run the AC on full blast while burning a raging fire at the same time.
 
why not just gather up a couple little electronics parts, and a few 12v fans, and build yourself a temp controller...

if you can solder, or are willing to get the tools and learn, you can do this for little to nothing...

check out this page......
The Heatsink Guide - All about PC cooling

i just built this today outta parts i had laying around(ok not fair, i'm an electrical engineer) but the parts wouldnt cost you more than say 10 bucks plus a wallwart and the fans....

if you wanna i can help you set this up and get it working.... in the vid below, the heat of my finger is enough to get the fans to speed up....


[ame]http://www.youtube.com/watch?v=OGGLuPdYVb8[/ame]
 
Last edited:
tankedchemist said:
AG, that's a really high base temp, imo... mine with no heater goes down to like 73. How warm do you keep your house? do you have a lot of surface area for water to evaporate from? How far from the top of the tank to your lights?
Click to expand...

That's not an unreasonably high base temp. That will be determined by the equipment she's running. My tank gets to around 86 to 88 with just the equipment. I use no heaters. And the lights contribute nothing to that -- it stays the same whether the lights are on and off. It's because I have a lot of big pumps running my system, and big pumps put off a lot of heat. A clip on fan drops it down to about 78, so it works out okay.
 
wow! jeesh, I thought I had problems in the biocube last summer with lights-off temp being 80.

I guess maybe I'm just paranoid about heat build up-- I lost a lot of coral last summer when we had a heat wave. I guess in AZ it's always hot so you might not have the inconsistent temps I get.... I dunno. I just know that I like my temp a bit lower "just in case"....
 
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