Newbie with a temperature question

[rachelcb80]

I'll admit right off the bat how much of a newbie I am. I've had my set up for exactly 11 days now. Go easy on me folks.

I live in the South so obviously have a/c and keep it set on about 74-75 during the warm months. My tank is keeping a constant temp. of 80. This is without any lights running. It's a 125 gallon, sump underneath (with all the gadgets in it), been up and running for over a week with 130 lbs of live rock (no fish yet obviously, only life in it is the stowaway snails and hermit crab that came in the live rock). I've got the light timer set for a couple hours in the evening and those couple of hours knock the temp up to 81. (No metal halides, just VHO's and actinics) I can only imagine what my temp will reach with the lights running their full 12 hours.

My husband is going to install a couple fans in the canopy to pull some air through there across those lights but is that really going to help enough? At this point a chiller is just not in my budget. (I didn't think I'd need one with our a/c going all the time!) If I kick the a/c down to about 72 will that help? We're winding up the hot season and in a few months the heater will be on and I keep that set at about 69-70. Anyways, I guess my question is, between some canopy fans and turning down my house temp, should that be sufficient enough to keep my tank in a lower, safer temp zone? Any other things I can try?

Thanks!
Rachel

[tkeracer619]

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Your husband is correct when he is going to install fans. This will more than likely cool the tank more than enough.

I cheap alternative to a cooler is an evaporative cooler. Basically you need a plate of acrylic with fans mounted to it sucking air from one side to the other. When you place the plate of acrylic on top of your sump sucking air out you create more evaporation but also cool the tank dramatically. I have an evap cooler set to come on if the tank gets too warm. Fans on the lights keep it cool for the most part.

As for turning down the AC. I would wait to see how the fans work. Have him install the fans to pull hot moist air out of the canopy.


One more thing. Keep some 2 liter water bottles in the freezer, In case of emergency you can put them in the sump and cool the tank down a degree or two.

[bertoni]

I target 82 F as the base temperature for my tank. I wouldn't let the temperature drop below 80 or so.

Fans can do a lot of cooling, so that should work, but watch the evaporation rate. I saw a huge increase in evaporation when I used a fan during some very hot weather here where I live.

[rachelcb80]

Mark, definitely will be installing those fans this week or weekend. Guess I'll leave my thermostat where it is for now and see what the fans accomplish. Thanks for the emergency idea with the water bottles. I will store that idea away for sure!

Jonathan, are you able to keep your tank at a constant 82 or is that the low end when the lights aren't on? Everything I've read thus far gives the general recommendation of 75-78 (or some say 75-80) so I was thinking I was really on the high end of the scale. I've read the biggest problem with the higher temps is the lesser amounts of dissolved gases in the water and that oxygen can become in real short supply. With an open tank and an open sump, am I getting enough surface oxygen exchange to avoid this problem?

I was pretty sure I would see my evaporation rate increase quite a bit but figured that was a necessary evil to keeping the temp in check. I think I know the answer to this question but do I run the fans 24/7 or only when the lights are on?

Thanks again!
Rachel

[bertoni]

The tank varies somewhat, depending on whether the lights are on and the inside temperature. It peaks out at around 84-85 during the summer.

The temperature doesn't make enough difference in the oxygen level to be interesting, in the range we're discussing. This page will give you some data:

http://www.aquanic.org/images/tools/oxygen.htm

This article discusses water parameters, including temperature, and points to a number of references:

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

The low temperatures you mentioned were recommended once upon a time, and some references still list them.

[mg426]

I think the fan thing will do the trick for you. I keep a loaded 125 with MH lighting around 81 to 82 tops in the summer. AC set to around 75.