Heat from light question

[Ann1214]

Heat from T5 (sunlight) unit
I have the T5 8 bulb set up. I have been using it for about 2 weeks, and I think I might be heating the tank up too much. I have a 100 gal tank, and the temperature was at 80 degrees when I got home today. (It was at 76 degrees this morning.

I can put the lights on with 4, or 8 bulbs turned on. How far off the top of the tank should the system be? do I run all eight lights?

Sugesstions?

Hobby Experience: new

 

[Andrew]

Are they mounted in a canopy? If so then put some fans in the canopy and if they aren't and theres a space between a tank and the lights, run some rans across area between the lights and water to prevent the water from getting too hot.

 

[bertoni]

I target 82 as the base temperature for my reef. There's a lot of references on the subject.

I would run all eight lights. You might want to add a fan if you really want your reef at 76.

 

[SeanySean]

How deep is your tank, my PC's are about 2" away from the water (as close as they will get with the glass)

Do all of them turn on at the same time?

 

[Ann1214]

My tank is 24 inches deep. I am just starting up - all I have in the tank at the moment is live rock, live sand, a few snails & hermits. Right now I am running all 8 bulbs. (I am trying to get my equipment sorted out).

I do not have a canopy - and I am using makeshift "legs" for the unit. (until I can get something better). they hold the light about 6 inches off the top of the tank.

What does it meant to "run some fans"? What kind of fans?

 

[bertoni]

Usually the small muffin fans for electronics work well, but any fan will do, if pointed at the water surface. You might want to consider autotopoff, since the evaporation rate will increase.

 

[Ann1214]

atopoff?

Not to sound too ignorant - I have glass covers over the tank. I assume this helps with evaporation. I would be afraid of salt water on the lights without the glass covers. Am I wrong?

 

[Andrew]

An auto top off replaces water thats lose durning evaporation for you so you don't have to. Check out autotopoff.com

 

[SeanySean]

Yes and no, salt water will not evaporate, just water, which causes rhe same problems, only slower.... if you have glass covers then you should not worry about the evaporation
auto top off is when you have a switch of some kind that detects when your water level is low and turns on a pump from a fresh water source to top the system up - Great for holidays, lol

T5's produce heat but IMHO not enough to worry about fans etc, MH's yes

also t5's at 24" is pushing it at sand level

 

[Ann1214]

I know - but I have lots of live rock, and have arranged it so that I have lots of ledge space at mid tank and upper tank levels.

I am only starting up & will not try anything other than soft corals and mushrooms for some time.

 

[SeanySean]

OK, so depth of light penetration is not an issue, do you stagger your lights i.e. 4 on, an hour or so later the other 4, and vice versa. This will help with heat and will provide a better environment for the little fishies

 

[Fast Fred]

Unless you have some serious splashing going on in your tank, or if you keep escape artists, ie eels, octopuss, you may want to consider removing the glass tops from the tank. Evaporation is a cheap way to cool off a tank. Fans will help with the evaporation as well. By doing this, you may want to either keep a close eye on the water level and salinity, or investing in an auto topoff system.

 

[Ann1214]

Thanks - you have given me some great suggestions!