Too much light?

S

sharko88

Can you have too much light on your reef tank?

I currently have 2 x 150w MH and 2 x 39w T5's on a 58 gallon aquarium (36"L x 18"W x 21"H) and I am thinking about getting rid of one of the MH's to save money. I have a 4" sandbed on the bottom.

If I got rid of the one light, I would be going from 6.5 watts per gallon to 3.93 watts per gallon (actually both would be higher numbers because of water displacement from rocks and deep sandbed).

I am also making some changes to my tank (getting rid of some coral) and want to really only have mostly LPS, some SPS, some zoas, and a clam. I think these should be fine in both situations, but am unsure.

So do you think I had too much light before (6.5 watts per gallon)?
 
You can have too much light for your flow. As Jake Adams mentioned at next wave, there's a point where too much light doesn't do any good as corals can't get nutrients and remove waste efficiently.

If you bump up your flow, corals can process more nutrients.
 
I think my flow is pretty good. I have 2 x koralia 1s and 1 x koralia 2 in that 58 right now. Like I said, I am interested in seeing if I can drop the one MH and still be good for SPS and clams. I am trying to lower my yearly bulb replacement cost (if the extra light isn't doing much more for the corals and only increasing my chances for an battle with nusiance algae).
 
You could put SPS/Clams directly under the halide. I had one over my 30long tank and I had shadow areas on each side of the tank. You also may want to add more flow. I've got close to 5000gal/hr flow in my 75gal tank. Since they are on a controller, it probably is more like 3000gal/hr since I don't run all my pumps at full blast at the same time.
 
I don't know if I need any more flow. I want to keep mostly LPS and they don't like that much flow. It is not going to be a SPS only tank and I know my hammer and frogspawn have tucked away back into their skeleton if I have too much flow pointed their way.
 
@sharko88 wrote:
I don't know if I need any more flow. I want to keep mostly LPS and they don't like that much flow. It is not going to be a SPS only tank and I know my hammer and frogspawn have tucked away back into their skeleton if I have too much flow pointed their way. said:
Don't confuse overall flow with "flow", having 3000gph of chaotic, random flow is not the same as 3000gph water cannon blasting at a coral. :lol: Just situate it so sps are high and adjust the powerheads so top half has more of the chaotic flow and the remaining tank has good overall flow that is sweeping lightly across the sandbed. May take a bit of trail and error to get the placemment's right so everybody is happy. :D

Cheers,
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Ron is correct. My 3 tunzes are on a controller and they are constantly adjusting from 30% to 90% of their max flow.
 
Also, you might consider just getting rid of your current setup and going with all t5. I did that on my 30long and love it. I got a Current 6 bulb fixture and it makes my lps glow. Also cut down on the heat produced.
 
10 watts per gallon is about the max.

I currently run two 400 watt MH's + two 96 watt PC actinics over my 18" deep, 6 foot long, 100 gal tank... Right at 10 watts per gallon, and the SPS and clam love it, the LPS and others i put in the shadows.

Too much light for LPS corals will cause them to be a lighter color.[/b]
 
@aentrop wrote:
10 watts per gallon is about the max. I currently run two 400 watt MH's + two 96 watt PC actinics over my 18" deep said:
The watt's per gallon myth is just that....a myth. You also can't count all of the actinic wattage in that calculation.

Cheers,
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@Opus wrote:
Also said:
I have considered this. It would be the cheapest route (yearly costs - both electricity and bulb replacement). I just don't know what I can get for my 2 x MH retrofit kits.

If I went the route of all T5s, I would go with 6 of the 39watt ones. That would put me at a total of 254 watts which is 4.034 watts per gallon in a 58 gallon (not accounting for water displacement and the deep sandbed).
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Stop even thinking about watts per gallon - it means nothing. Think about the depth of the tank instead. Can the current light penetrate to the sand bed and still allow you to place anything you want there? A single 150w HQI can do a good job up to about a 20" depth. 24" - 250w, 30" - 400w.

You could have a 100 gallon tank that is 8 feet long and only 14 inches deep (an example - not real life measurements). You wouldn't need very strong lighting because you only have 14" or less with sand of water to go through.
 
I know the light is easlily penetrating with my raised sandbed. The depth is only 17"-18" with the deep sandbed. I am kind of curious though on t5 penetration. Does anyone know what watts are recommended for what depths? I know 6 x 39 watts on a 58 would be enough to keep anything, but have never seen figures on t5 lights. Anyone know?
 
Talk to the GrimReefer or RTParty on ReefCentral. They have some real good T5 info. The watts on t5 is a matter of the length. A good ballast like an icecap 660-009 will overdrive the bulbs and effectively increase their wattage/output. Use a good ballast and great reflectors. ATI and UVL bulbs top the PAR charts at this time and all can be had through reefgeek.com. Greg at reefgeek can steer you in the right direction if you explain your tank to him.

T5 light tends to surround the rock and corals and eliminate shadows for the most part. Different reflectors come in various widths so you simply want to fit as many as you can, usually, within the confines of your canopy. You also need a good cooling solution with t5s especially if you're overdriving them. Mainly the light and heat is spread out over the tank and not so concentrated so the temperature control in the water is generally easier to manage.

Lastly, you can completely customize your 'look'/coloration/growth potential using t5 bulbs. They come in many different colors and wavelengths so you can make the tank look any way you want.
 
I was looking at the overdrive option. Does anyone happen to know what the lifespan of bulbs are then when overdriven? I have read it shortens the lifespan, but by how much?
 
@sharko88 wrote:
I was looking at the overdrive option. Does anyone happen to know what the lifespan of bulbs are then when overdriven? I have read it shortens the lifespan said:
Most suggestions are to replace overdriven bulbs in 6-9 months. Quality of bulbs and cooling solutions make a big difference.
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Well, I am now looking into ditching the MH's completely and going with 6 x 39 watt T5's (probably not overdrive). I am looking at the retrofit kit offered by hellolights.
 
I overdrive T5's with an Icecap Ballast, and my last set of bulbs got 13 months out of them. Then I began to notice some nuisance algae growing faster than usual so I changed them out.

So I'd say 11-12 months for overdriven bulbs.
 
@aentrop wrote:
I overdrive T5's with an Icecap Ballast said:
Not to disagree but I disagree... as mentioned..... you get 9-10 months of use before the par drop's way off and the spectrum shifts. Why squeeze 2- 3 months out of bulbs, then spend a fortune trying to combat resultant algae issues, not to mention it's possible effect on coral growth/coloration. Another problem with extended bulb changes is that your coral's can suffer from light shock, with the drastic increase in output from the new lights. If you are gonna overdrive the bulb's there will alway's be a compromise, if you are not willing to accept the compromise then don't overdrive. :D The hellolight or reefgeek setup's are pretty good, you won't be dissappointed with either, you may want to see if you can select the bulb types to get you the look you want as also mentioned above. :wink:

Cheers,
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