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brwiley

Lighting and Chillers

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6 Comments
by
brwiley
, 11-13-2010 at 12:45 PM (1700 Views)
As I contemplate options for modifying the sump on my 65G display tank, I'm also faced with question about plumbing and lighting. My existing setup includes a separate submersible pump that feeds a Teco T20 (1/3 HP) Chiller. It runs pretty frequently, but does a good job of keeping temperature in a nice tight range. I've noticed very few people on this site even mention chillers, which made me wonder how common they are (especially here in TX).

Something in my system imparts significant heat to the water, but I'm not sure which component to blame. The return pump is an external GenX PCX40, but probably oversized enough that it's not doing me any favors with respect to heat input. The chiller and skimmer pumps are submerged, but "right sized", so there's not much I can do to change that... well, almost nothing. I am considering using a second flow loop off the return pump to run the chiller, which lets me pull one pump out entirely.

The other heat source is obviously the lighting. The 2 CFL's and single 150W DE MH do put out some serious heat. I do have a single 100 mm cooling fan on my hood, but it sits too close to the wall and therefore could be moving more air (if only the tank didn't weight so much I'd move it... on my list of things to address when making my upgrades). The fixture is due for a replacement, so now's the time to correct things with respect to heat contribution.

Anyone have any thoughts of which of these heat sources is likely the biggest contributor? Realistically, should a chiller be needed at all on a system this size if the heat sources are managed well? Any feedback regarding running a chiller off of the return pump?

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Updated 11-20-2010 at 01:25 AM by melev

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‎ Questions - Need some input

Comments

  1. Midnight's Avatar
    Well, height above the water will have an impact on lighting, also the ambient temperature of the room where the tank is has a significant impact. I would suggest running your return pump through the chiller to alleviate the need for a third pump. Get a nice lumabright reflector so you can get that light 12 inches or more from the water. I there a hood on the tank if so so pictures would help identify a practical solution.
  2. mledford's Avatar
    I'll also have to comment and say the 150MH is more than likely your biggest heat contributer. Also, I have had faulty heaters before. Just as a thought. I had a heater that you could set on 76 and it would heat the tank to 84. I scratched my head a few days, replaced it and killed my heat problems...
  3. brwiley's Avatar
    Thanks for the comments! Sounds like you both are leaning towards the lighting as the culrpit. Ambient temp is 76F in the summer and 72F in the winter, and I have the chiller programmed to cut on at 81F and off at 78F. Right now the lighting is about 7" from the water surface. The photoperiod for the MH is only 4 hr per day (used to be 6), and the CFL's stay on 8 hrs a day for dawn/dusk. I'll take a shot of the hood later and post it. So mledford, do you think 150 W MH is too much for this tank? It is a deep 65 G (18"), but this was the lighting system on it when I inherited it from a friend 3-4 yrs ago. I've been leaning toward an all T5 system as a replacement, but I'm just not all that confident in the lower intesity levels and spectrum change. Also, I don't a heater in the system at all right now. The chiller can run a heater off the onboard controller, but I've never had a problem with things getting cold, so I yanked the heater altogther awhile back.
  4. melev's Avatar
    The 150w MH bulb is a little too close to the water. 9 to 12" is better, and that reduces the heat being added to the water.

    I don't run a chiller and I live in Texas myself. I've never seen the need for one since I keep my home at a comfortable temperature. However, if my HVAC fails, the tank could overheat because I don't have one. Chillers add heat to the room they are in, something your HVAC has to overcome.

    Your fan may be recirculating the same heat in a circular fashion because it is so close to the wall. Better to blow in cooler ambient air from the room into your canopy.
  5. brwiley's Avatar
    Thanks, Melev. I've seen your website and your previous 280G system here in DFW... so that had no chiller, eh? I seem to remember a picture with dedicated AC window unit in the fishroom though, right? If so, did it have to work hard to keep the room at temp?

    I'm in the middle of making some plumbing and sump upgrades (thanks for your feedback on that as well). I sucessfully added the secondary flow loop for the chiller to run directly off my return pump as mentioned in the original post (elminating one submersible pump), as well plumbing to support a very small (2.5G) refugium intended for some chaetomorpha that will reside above the main sump (only 17 G).

    Lighting is next on my list of upgrades. Do you think the 150W MH + 2x65W CFL arejust too much wattage for a 65 G tank or am I just not doing a poor job of dissapating the heat they generate?
  6. melev's Avatar
    The AC was an 8000 BTU window unit. During the warmer months, it runs around the clock. From my measurements, the compressor was on 12 hours out of each day, and it cost me just over $1 per day to run it. So for $33-$35 a month, the fishroom stayed nice and comfortable. It never had a hard time keeping up, as it is set to keep the room 75F usually. In the cooler months, I may run it only during the day time if necessary, but usually it was as simple as opening up the door a couple of inches to let the cold air from the garage enter the room. In the dead of winter, the room was kept shut and the lighting warmed things up enough while the tank didn't get hot. At night if the temperature was around the mid 30s, I'd turn off the vent fan in the ceiling to avoid making the temperature drop too much.

    I think a single 150w MH and 2 CF bulbs shouldn't be a factor at all and your tank could run cooler with a few small adjustments.