View Full Version : Looking at the cheapest and best way to convert my MH lighting to t5 on a 200g

06/13/2010, 05:00 PM
I have a 200g Oceanic tank. It measures 7 foot by 2 foot, or 84'' by 24''. I'm looking to convert from using two 400w MH to the t5's. I'm looking into this because of heat problems and energy. My tank has a custom made canopy with two 4'' fans. My chiller runs non stop when the MH come on. I thought about buying a larger chiller, but it makes more since to remove the MH's. I'm not sure how many t5 lamps I will need, I'm thinking at least six deep, but the length of my tank makes it hard to decide what size t5 lights I should buy. Cheaper is always better. So if anyone knows a good retrofit kit, what size, how many bulbs, and were to buy them from.

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06/13/2010, 05:54 PM
Cheap and best are often mutually exclusive catagorys in this hobby I've noticed. You might want to look on places like craigslist/ebag for used equipment or the like. I also had luck for a while using industrial warehouse t5ho fixtures. 8 bulb 2'x4' fixtures. Supposedly replaces a 400 watt MH. I've since replaced mine do to finding a deal on some narrower fixtures.

06/13/2010, 06:06 PM
Unfortunately there really is no "cheap" way of doing this, especially on such a large tank. Of course your cheap"est" method would be to buy a retrofit kid and wire the lights into the canopy yourself. Check out www.reefgeek.com, they offer a variety of different lighting options. Ice Cap makes a quality kit. By the time you sell your existing light rig you may come out spending about the same. Maybe you could try and trade evenly with someone?

Keep in mind that T5's do get pretty warm as well so switching over to them is not the magic answer to all your heat problems. Your best option would be to get some real good airflow going through your canopy. Maybe drill the sides and have 2 120mm computer fans on each side. One side blowing air in and the other out. You will have to do this whether you use T5's or MH's so it might be worth trying before you invest in a new setup. Also, with T5's I would go no less than 8 deep on a tank your size.

06/13/2010, 06:10 PM
800W for an 8' tank is not that bad. If you used a combo of 4' and 3' T5s to cover the 7' tank,

12 bulb setup
6 x 54W = 324W
6 x 39W = 234W
Total = 558W

16 bulb setup
8 x 54W = 432W
8 x 39W = 312W
Total = 744W

The 16 bulb setup is basically the same power as you use now. 2 x 4" fans sounds very minimal for cooling that setup. Have you thought about improving the cooling?

06/13/2010, 09:12 PM
i agree in trying to increase your airflow. my t5's heated the tank the same amount as my halide. you best bet is to run 250w halides and a larger fan.

to answer your question you would need 8 80w (5') bulbs staggered for the bare minimum better would be 16 36w or 8 80w and 8 24w. anyway you look at it you 24" deep and that's cutting it close on t5 penetration. bulb cost alone is over $350 every 9-12 months. figure in the initial reflector/ ballast or fixture(s) cost and its a no win situation.

06/15/2010, 11:26 AM
I made the exact same light swap for my 7 foot X 2 foot 210 gallontank. I replaced the 2 400 watt MH with 2 homemade light boxes mounted under the hood. each box holds 4 - 4 foot 54 watt T5 bulbs with icecap SLR (single light reflector). The 4 foot bulbs overlap in the middle by 18 inches. I chose not run the lights all the way to the end of the tank, bulbs over the center 6 feet of the tank. The boxes are 1x4 wood with a plywood back. I cut slots along the 1x4s and slid in a sheet of plexiglass from Lowes to help with cooling the bulbs. Each box has two 4 inch computer fans blowing into the box over the t5 endcaps and into the middle of the box where it exits through holes in the back plywood. The T5s are powered by 2 icecap 660s, 1 per box mounted remotely.
These 8 bulbs have plenty of PAR to grow any LPS or SPS corals I have tried.
I do not have a chiller and I do not notice any extra heat in the room like I had with the MH. I live in Florida and the a/c runs most of the year. Tank temp can run in the low 80s but never had any problems with heat. I do run a fan on a timer in the sump to help with cooling and evaporation for my Kalk makeup water.

06/15/2010, 07:31 PM
My vote is for 250 watt MH with good reflectors.I thought of switching at one time,but i think 250's are cheaper to run.1-in bulb cost,And 2nd if all of sudden you need to run a heater that little power savings all went out the window if there is any.But if you don't, you make it up with bulb cost.