MH's and chillers

If you use MH's do you run a chiller?

If you dont run a chiller and use MH's do you have temp problems?

What are your MH's and how far off thew water are yours set?

Trying to decide if I want to upgrade to MH's and if I would have heat issues.

Looking at 2-250 watt 20000k on a 24" deep 90 gallon tank in an enclosed hood. Lights would be 12" off water surface with three exhaust fans.

 

I have 2 250w on a 180 gallon . 6" off the water. Less than most similar setups. No heat issues here but the main thing is the room temperature. I keep it at 72 most of the warmer months. No chiller. The people I know around here that run chillers run their home temperature much warmer. One guy told me his electric bill would be $1000 a month if he kept the house at 72. It was quite warm in his house. I have fans that I can run if necessary but haven't turned them on. I suppose I could run the home a few degrees warmer with the fans running or add another 250w and still be ok without a chiller.

 

I have a 150w MH on a 20g with no chiller. I don't have AC but I just put a fan blowing across the surface of the water and it makes a big difference. You have to top off your water like crazy though. I'm too poor for a chiller....

 

I don't run a chiller, but I'm right on the line between needing one and not.

My tank is 80*F pretty much around the clock. I run my home at 70, never shut the AC off.

I have 2-250's, 20K, that sit 5" off the water's surface.

I think unless you run your house as cold as mine, you'd certainly have heat issues to the point where you'd need a chiller.

Like you, I run a 24" deep 90G tank, but I have an open top. I think with a canopy, even with 3 exhaust fans you'd be cutting it close.

As I'm sure you know, there are lots of variables in this hobby. Having your tank about 6 inches from the wall behind it makes a difference just from the air movement. I use an inline return pump, and feel that not having a submerged return makes a considerable difference. I run a Vortech for in-tank water movement, and since the motor is outside the glass, that helps too.

I upgraded my 2-150 MH's to 250's just a few weeks ago and only now am I right at 80*F water temp.

So, since home is 70*F full time, my return is not submerged, I don't run a canopy, and my main water mover in the tank has an external motor--I feel it's only for these reasons that I'm not forced to run a chiller. I am so close, though.

I think you'd probably need one.

 

I too removed the canopy on my 75, 22" tank, w 150w 14k MH, right around 7" above tank. Usually sits around 77 for temp. I use a small desk fan from walmart, hangs on the side of the tank, blows right across surface of water. Room temp is 77 mostly. Removing the canopy made a huge difference for me. Also, I position my return pipes (2) to disrupt the surface water, I can feel the cooler air from the water flowing like that.

 

200 gallon long which is 24" deep. I am running 3 250W, 14000K MH's along with 4 54W T5's. I have absolutely zero temp issues, and still have not used the A/C in the house, even on a 100 degree day. Lights are 4" off of waters surface, open canopy, no exhaust fans.
Highest temp the tank has reached is 79.2

 

Like AV8 and Sparky said, there are a lot of variables.

I too have a 90g. I HAD 2x150w MH, closed top, sump under my tank, 2 Mag 7 pumps as well as my Mag 9.5 return. I didn't own a heater. Chiller ran with the MHs. It was just a 1/10 HP. But that was trying to keep the tank at 78F

I decided to bump my tank up to 80F. I went to a 58g sump/fuge in my stairway closet, took out the two Mag 7 pumps, took off the tops, and had to put in a 400w heater. We have not had any hot days yet, but I could not keep my temp up at all.

Now I changed my 150w to 250w, and my tank will get up to 80.5. I moved my lights up 3 inches to 7 total and that seemed to be enough for now. We still have not had a hot day, I don't have AC, but my tank is in the half basement.

So it just depends. What your other heat inputs are, what your surrounding temps are, and how you can get rid of heat. Also, where you live matters. Colorado is dry. I can evaporate more water, and loose more heat, than my counterpart in Florida. I hope I don't need the chiller cause I would like to get rid of it. I'm sure a fan would be enough.

 

Great info guys. Thanks.

I have 2 powerheads and a submerged return pump all of which would add heat. I have been thinking about replacing the return pump and splitting the return lines to get rid of the powerheads, sounds like an external return pump may be a good idea also.

I built the canopy to house the lights, keep the fish from jumping out and clean up the look of the tank. I have no issue cutting more holes in it and adding vents. The three fans I have are all set along the back, two blowing out and one blowing in. I could add one on each end also to blow across the lights. I cut four holes in the top to line up with the light fixtures built in fans and could use those for additional circulation when i change to MH's.

4 or 5 more fans and adding some vents would be a lot cheaper than a chiller. I live in Indiana which is fairly humid all year round. I keep the house at 72 year round mostly for the tank.

I know how i like pictures so here are some of the canopy i built for no real reason.

 

more pics

 

I also have a 90 with (2) 250w MH and no chiller. I run my a/c @ 73* all day and have two fans controlled by the AC-Jr. One fan blows right across the top of the DT and the other is facing down in the sump. My temp flucuates from 78(lights off) and 79* when the lights are on. Like everyone has said, every situtaton is different. I probably would have bought a chiller if it werent the fact that they are expensive. But the fans do do a great job at a fraction of the cost.


Luna