- This topic has 5 replies, 4 voices, and was last updated 17 years ago by Saint2966.
January 20, 2007 at 7:26 am #1091carrieincoloradoMember
I have been considering adding a metal halide pendant to my erectus tank. It\’s 40 gallons, and right now has 130 watts of PC lighting, white and actinic. I am considering it because I know that the mushrooms, zoos, poly\’s and colt corals would love it…. but would it bother the horses? I\’m thinking of a 150-250 watt MH turned on for 4 hours between 2 and 5pm. Does this sound like a bad plan?January 20, 2007 at 10:28 pm #3323KrisGuest
The lighting isn’t likely to bother your SH.
Mushrooms are not going to like that lighting. Most mushroom’s are fairly low light corals. So unless they are at the bottom of the tank I wouldn’t do it!
Also, Mh’s put off alot of heat! You may find you’r tank temp going up even with that short of a foto period. I would recomend a fan blowing across the top of the tank to keep it from getting to hot for your horses.
If you did bump up the lighting to MH you could keep some of the higher light corals.
Maybe Pete will come along and elaborate.
KrisJanuary 21, 2007 at 2:27 am #3325Pete GiwojnaGuest
As Kris said, metal halides will work fine for seahorses providing that overeating doesn’t become a problem and that you also provide some well-shaded areas for your ponies when they would like to get out of the bright light. ‘Shrooms generally prefer relatively light and most of the other corals you mentioned don’t require high-intensity lighting either, so unless you were planning on adding some SPS corals to your collection, a major upgrade in your lighting system probably isn’t really necessary. A cooling fan will probably be needed to deal with the heat generated by the metal halides and it’s sometimes necessary to add a chiller to the aquarium to keep the water temperature stable in the comfort zone for your seahorses when high-intensity lighting is used.
Here’s the rundown on lighting a seahorse tank with live corals or a reef tank that will house seahorses, Carrie:
Lighting the Seahorse Reef
When it comes to lighting, seahorses do not have any special requirements other than the fact that most species prefer low to moderate light levels rather than excessively bright light. They have a corrugated retina especially rich in rods, which gives them excellent visual acuity under twilight conditions and low light levels in general. But this does not mean that they shun bright light, just that they appreciate shady retreats as well as brightly illuminated areas.
In actual practice, seahorses will do well under any type of lighting you prefer — from metal halides to power compacts or VHO lighting to daylight fluorescent tubes to ambient room light — providing shaded areas are available to them and overheating does not become a problem.
So don’t scratch seahorses off your list of reef-safe fishes just because you keep corals that require bright light. Hippocampus is often displayed under metal halide lighting at public aquaria and zoos (Seahorse Husbandry Manual, 2002), and I know many reef keepers who keep seahorses in their systems under metal halides. Often the reefers will keep the coral and inverts that require strong light at one end of the tank, where the metal halides are concentrated, and keep the other of the tank shaded to accommodate the seahorses, reserved for corals that don’t need high-intensity lamps. Or they will use pendants as spotlights, focusing the metal halides on the areas with corals that require the strongest light, and leave other areas of the reef less brightly illuminated. This can produce a very attractive affect similar to sunbeams filtering through broken clouds. If need be, you can also provide shaded areas by positioning sections of aluminum foil atop your aquarium that are the right size and shape to cast shadows where you want them below.
In fact, my primary concern when using metal halides on a seahorse tank is the water temperature rather than the intensity of the light. Metal halides throw off a lot of heat and most of the subtropical/tropical seahorses do best at temperatures of around 73°F-75°F (23°C-24°C); so avoiding temperature spikes above 80°F (27°C) is very important.
Personally, I like to provide my seahorses with a natural day/night period that includes twilight periods at "sunrise" and "sunset." To accomplish this, I like the power compact (PC) light fixtures that include two tubes — one actinic and one daylight fluorescent — with dual ballasts so that each ballast can be placed on a separate automatic timer. I like to have the bluish actinic come on before the daylight tubes and stay on after the daylights go off, thereby providing a simulated dusk and dawn (Giwojna, unpublished text). This is important for seahorses since they conduct most of their courting and breeding in the early morning hours under twilight conditions. It’s a neat effect and fish and invertebrates can then anticipate "lights out" rather than being plunged into total darkness at night or suddenly thrust into bright light in the morning. I also adjust the timers to lengthen or shorten the daylight periods in accordance with the changing seasons. I find that maintaining a natural cycle this way aids reproduction (Giwojna, unpublished text).
In short, I find PC lighting to be a good compromise for a seahorse system. Power compacts provide plenty of light for macroalgae or the seahorse-safe soft corals in a modified reef system without being too bright or generating too much heat, and the dual ballast system allows for a natural day/night rhythm that changes with the seasons. The resulting dusk and dawn facilitate courtship and help the seahorses maintain a natural reproductive cycle (Giwojna, unpublished text).
For all intents and purposes, you really can’t go wrong no matter what lighting system you chose as long as you provide both shaded areas where your seahorses can escape from the light altogether and well-lit areas where they can bathe in bright light as they please. You will find your seahorses will move into and out of the light often, seeking the comfort level that suits them at the moment.
Best of luck with your lighting upgrade, Carrie!
Pete GiwojnaJanuary 23, 2007 at 11:34 am #3332Saint2966Guest
Just an opinion. I wouldnt add MH to a seahorse tank. I am currently spending lots of money to downgrade my lights. I recently upgraded my tank to a 120 Gallon with trickle and sump, built in refugium. I have a mixed coral tank with LPS, SPS, Leathers and Mushrooms. The system I purchased included Metal Halide lighting with T-5 with blue and white actinics. My corals loved it. My seahorses… well they went into hiding, and I have hated myself ever since. They actually tucked themselves under rock caves and hid in corners buried with plants. The tank looked barren. I removed the entire canopy and am in the process of reworking it. I have already purchased LED Moonlights at $69.00 ( to reduce the bright effects on dusk to dawn). as well as three timers @18.00 ea. (1 for the actinics to run all day , One for the halides for short periods daily, and one to control the moolights AM and PM) 2 new actinic bulbs with lower watts and higher Kelvin (to reduce the glare) @ $35.00 ea. Currently I am running a Power Compact and the babies are greatful. I am getting to enjoy them again. I missed the dances, and games they played, and for the first time I ended up fighting at meals noone even wanted to come out to eat. I target fed every meal while those lights were running. So I got to invest alot of money actually downgrading a system to satisfy my horses. The corals will have to live with it. Everyone is back to eating dancing and behaving normal with the new lighting system. Most of the mushrooms and leathers actually prefer the lower lighting some of the hard corals thrived with the higher lights but survived under the PC. Good Luck with your decision. Hope you dont end up spending more to downgrade after the initial upgrade cost.
Total cost to downgrade $193.00 plus tax, and I am not even sure this will work.January 24, 2007 at 6:39 am #3334Pete GiwojnaGuest
Rats! I’m very disappointed to hear that you aren’t able to use the metal halides and canopy that came with your aquarium upgrade; if you have to replace the lighting system, that makes the upgrade that much less of a bargain. Still a very good deal, but I know the gargantuan task you undertook to get the new aquarium set up your house, replace your old 55-gallon tank, and transfer all the corals, seahorses, and other specimens to the new system with the least possible stress, and I badly wanted everything to go smoothly for you. You did an excellent job with all of that and pulled it off nicely, only to discover that the metal halides on this tank are a bit too overpowering for the seahorses. That’s a darn shame…
I know many hobbyists who do use metal halides on seahorse tanks quite successfully, but there are a few tricks to it. For instance, you have to avoid overheating and you have to provide the seahorses with well-shaded areas they can retreat to when they would like to get out of the bright light. Often seahorse keepers accomplish this by confining the metal halides to one end of the tank, while keeping the other end of the tank relatively dimly illuminated, or using pendants for the MH to use them as spotlights to sort of highlight certain areas of the tank or corals that require high intensity lighting, leaving the rest of the tank well-shaded. And often the metal halides are suspended above the aquarium, rather than mounted in a canopy. That way, you have a little better control over both the brightness and the heat generated by the lamps simply by raising or lowering the suspended lights as need be.
Best of luck tweaking your lighting system and working out the perfect arrangement that works great for both your seahorses and live corals, Carrie!
Pete GiwojnaJanuary 29, 2007 at 11:02 am #3357Saint2966Guest
Hi Carrie, Pete,
Its working now. I added the led moonlights, automatic timers, and lowered the watts and increased the kelvin on the actinics one blue, and one white. The moonlights come on at 6:00 AM-8:00 AM. The actinics overlap about 7:30 AM and stay on till 8:30 PM, The metal highlides come on at 10:AM-2:PM,only 4 hrs daily, and run with the actinics. at 8:00 PM the moonlights come back on, and remain until 10:00 PM. I already had given the seahorses both sides of the tank for hiding places as well as plenty of caves in the center. I also had placed lots of extended artificial plants with height to shade certain areas. The seahorses still take refuge or afternoon naps during halide times, but at least this way, I can still enjoy watching them out and playing during the day, like before. The corals seem satisfied with the short sun periods. I just wont be adding any of the corals that need more lighting. The seahorses will always come first. the temp is maintaining at 73-78, It actually seems to stay cooler with the larger tank, even when the halides are on?? Now that… I cant explain.
Good Luck Carrie on whatever you decide. Thanks Pete for all your help in the changeover.
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