Sanjay or anyone please help me light my 47 gall extra tall

[Chihuahua6]

Sanjay or anyone else who knows at least half of what he knows can respond ; ) The tank is 20X18X30H. I plan to keep Yellow Fiji Leather, Torch Coral, a shallow water closed brain and debating on adding one variety of sps at the top (I know mixing sps and softies is not the best thing to do). I am trying to recreate an Indo Pacific reef flat so whatever I end up choosing will be a shallow water species. The easiest solution for me would be to use a DE pendant with 14000k bulbs however I think I would get better par with 10000k and supplemental actinics. With this option I don't know what fixture, ballast, bulb etc. to choose and there isn't much room inside the hood. I also considered 6500k bulbs since it's a shallow water niche I'm trying to recreate but I'm afraid even with actinics it will not be pleasing to look at. I want the corals to have some flourescence. I am guessing I would need a 250 watt bulb due to the depth. So how do I get decent par, asthetically pleasing color and a small enough size to fit in an 18X16" space? Oh did I mention I don't want to spend a fortune either?
Thanks in advance.

[Chihuahua6]

Anyone?

[pjf]

Sanjay Joshi wrote an article entitled “Underwater Light Field and its Comparison to Metal Halide Lighting� that may help. It was published in the August 2005 issue of Advanced Aquarist’s Online Magazine. In his article, he states that there is 14% light loss (86% transmission) in two feet of ocean water. By extrapolation, every 6� of water transmits 96.3% of the light:

06� of water transmits 0.963^1 = 96% of the light on the surface.
12� of water transmits 0.963^2 = 93% of the light on the surface.
18� of water transmits 0.963^3 = 89% of the light on the surface.
24� of water transmits 0.963^4 = 86% of the light on the surface.
30� of water transmits 0.963^5 = 83% of the light on the surface.

There is not much difference in light loss between an 18� deep tank and your 30� deep aquarium. Get a fixture that would generously illuminate the 18� depth tank and don’t worry about the additional foot of depth in your aquarium.

Do note two additional points:
§ Most of the light absorbed by water is in the red end of the spectrum rather than photosynthetic available radiation (PAR). High color temperature and clean water will help get PAR to the substrate.
§ Most of the light entering the water will reach your substrate because your aquarium walls will reflect it (total internal reflection). Clean walls help.

Make sure that you have adequate air and water circulation to keep your tank cool. An open top is ideal.

Consider compact DE HQI fixtures if space is a concern. The 20� Sunpod should be on your shortlist, as you do not have enough space for supplemental T5’s and its LED’s can be used for extended viewing. My vote goes to 150-watt HQI units with a longer photoperiod. A 250-watt unit may have too short a photoperiod for you to enjoy.

[Chihuahua6]

Wow excellent post pjf. I truly appreciate the time you took to answer my question in great detail. I have a quick question if you don't mind. Why would 250 watt have too short of a photoperiod to enjoy. Is it because of the heat gain or too much wattage in a concentrated surface area?

[msuzuki126]

You could always get some supplementary lights like T5 or VHOs and have them on before the MHs come and still be on a little while after the MHs go off.

[The Grim Reefer]

Because of the tank dimensions you are going to be limited to PC's for actinic supplimentation. A 250 watt 14K Phoenix running in like a PFO minipendant is going to be about the least you can get away with on a 30" tall. A lot of people run those with no supplimentation so PC's should be plenty.

[pjf]

Originally posted by Chihuahua6
Why would 250 watt have too short of a photoperiod to enjoy. Is it because of the heat gain or too much wattage in a concentrated surface area?

If a strong MH lamp were your only light source, you would be unable to view and enjoy your aquarium after it turns off for the day. Both heat and light will shorten its photoperiod. Heat because under a hood, there is less air circulation. Light because your aquarium is symmetrical like a hex aquarium. The reflective glass geometry will concentrate light on the substrate. Unlike a rectangular tank, your aquarium will not "leak" light through the side glass. The light strikes the glass with a more vertical angle and results in total internal reflection.

I did find a compact combination fixture that might work for you. The 13-1/2" x 15" x 6"H Sundial by Current USA comes with either 150w or 250w HQI lamps and includes integrated timers, fans, and actinic PC’s. Check to see if it can rest on the cross bracing of your hood.

[Chihuahua6]

Thanks again pjf. The hood isn't built yet so I could make that one work but I think I like the Sunpod with the moonlights better. With that Sunpod I would still have room to add a compact flourescent strip light if I wanted to and I like the fact that I can use it immediately since the hood hasn't been started yet. I was thinking of using the Sunpod as is with the 14000k bulb that it comes with and then later changing to a 10000k bulb and adding the actinics. Can I use any brand bulbs in it?

[The Grim Reefer]

[i]

There is not much difference in light loss between an 18� deep tank and your 30� deep aquarium. Get a fixture that would generously illuminate the 18� depth tank and don’t worry about the additional foot of depth in your aquarium.

[/B]

You seriously need to reread Sanjay's artical. Pay particular attention to the section where he mentions the "inverse square law". The percentages listed is for light loss caused by water in addition to the loss caused by moving further away from the light source.

[pjf]

Originally posted by Chihuahua6
Thanks again pjf. The hood isn't built yet so I could make that one work but I think I like the Sunpod with the moonlights better. With that Sunpod I would still have room to add a compact flourescent strip light if I wanted to and I like the fact that I can use it immediately since the hood hasn't been started yet. I was thinking of using the Sunpod as is with the 14000k bulb that it comes with and then later changing to a 10000k bulb and adding the actinics. Can I use any brand bulbs in it?

Manufacturers generally recommend specific ballasts for specific lamps. A picture of a replacement Sunpod ballast (http://www.marineandreef.com/product...50Wballast.jpg) shows that a Sunpark 120-MH-150 is used. You may want to contact either Current, Sunpark or lamp manufacturers concerning compatibility.

I believe that Sanjay Joshi has tested different lamps with different ballasts and published the results (www.reeflightinginfo.arvixe.com/articles.htm). Unfortunately, I don’t think that he has tested any ballasts or lamps from Current USA, the maker of the Sunpod. You can always start another thread!

[pjf]

Originally posted by The Grim Reefer


You seriously need to reread Sanjay's artical. Pay particular attention to the section where he mentions the "inverse square law". The percentages listed is for light loss caused by water in addition to the loss caused by moving further away from the light source.

If Sanjay's point source of light was under the open ocean, then the "inverse square law" definitely applies. That is not the case for aquarium lighting that is directed downwards by reflectors, bent towards the vertical by refraction at the water surface (Snell's Law), and totally internally reflected (TIR) by glass or acrylic walls.

In his article, Sanjay's model was the open ocean, not an aquarium "wave guide." Chihuahua6's cubicle tank resembles a hex tank in its optical properties. Assuming that your water and glass is clean, Sanjay's figure of 14% light absorption by 2 feet of ocean water is the most appropriate here.

[The Grim Reefer]

Here is the section of the article you refernce I suggested you re-read.

"Figure 9 shows the change in spectrum of the Iwasaki 6500K lamp just due to the water. In our reef aquariums this loss is quite small compared to the intensity loss due to distance from the lamp and reflector. For the Iwasaki lamp at 6" from the water surface, the loss due to 2ft of water is about 14%, where as the loss due to the change in distance from the source (from 6" to 30") is about 70-90% based on the inverse square law of light and depending on the reflector being used. In practice this loss will be lower due to the additive effect due to multiple lights, but will still dominate the light loss as compared to loss due to attenuation in water assuming clear water similar to the ocean."

I have taken 1 or 2 PAR readings in tanks in my day. Even with a perfect parabolic reflector (which doesn't exist) light degredation would be linear, Light intensity at 12" will be about double that at 24".
Don't take my word for it, here are some actual PAR readings taken at diffrent levels in tanks.

http://www.advancedaquarist.com/issu...03/feature.htm

[pjf]

Wow! It looks like there are contradictory results on this subject. Here's a few using fluorescent lighting:

http://fins.actwin.com/aquatic-plant.../msg00297.html
http://fins.actwin.com/aquatic-plant.../msg00301.html

[The Grim Reefer]

Never trust results from someone who puts their light sensor in a baggy to take readings (2nd link)

The point of Sanjay's artical was to demonstrate that the water in our tanks isn't deep enough to make a signifigant difference in spectrum(color of light) from the top to the bottom of the tank. In nature corals at the top of the reef will be hit with a broad spectrum of light while those further down will only see blue due to the water filtering out the less intense red and green wavelengths.

The percentages Sanjay refereced were for the addition losses caused by the filtering effects the water has on light traveling though it. Blue loses an additional 4% while red lost an additional 14% (I think I have the numbers right). While there is a change in spectrum from the top to the bottom of a tank it is insignifigant to what a natural reef would have from top to bottom. Those numbers are in addition to the 70 to 90 percent Sanjay refferenced being lost due to moving from 6" to 30" away from the source.

[pjf]

Originally posted by The Grim Reefer
Never trust results from someone who puts their light sensor in a baggy to take readings (2nd link)

Never trust results from someone who jams rocks and shade into his tanks and claims that its the water that is blocking light (orginal link)

[Chihuahua6]

Never trust results from someone who jams rocks and shade into his tanks and claims that its the water that is blocking light (orginal link)

While both of you have brought up some very valid points I have to admit that these were my thoughts exactly. With this in mind I should mention that with the tall narrow design of my tank some corals will be shaded to some extent by rock and other corals, although not completely. I have the rocks built onto a pvc pillar. It it narrow on the top and slopes out toward the bottom however it is a rather steep slope. With this in mind do you still recommend the 150 watt light or should I go with 250 watts? I was thinking of the PFO pendant http://www.hellolights.com/25pfomipe.html with the Icecap or PFO ballast (leaning towards Icecap due to the pricing.) I can add an actinic light strip later on if desired and a moonlight can be added later as well. I was thinking of using this with an Ushio 14000k bulb if it would work on either ballast. What do you think?

[pjf]

You are going to get different opinions but here is my two cents:

• HQI 150 DE for shielding, less heat, longer photoperiod & compact hood installation
• SPS on top, LPS in middle, soft corals at bottom
• Keep front, side & upper back surfaces clean for reflection
• Water circulation (www.advancedaquarist.com/2006/6/aafeature2) for respiration, photosynthesis & "glitter"
• Mount lights at least 5� (= 20"/4) above water’s surface over center of tank.

If your lights are mounted too low, some light will pass through the upper portion of your glass instead of being reflected back into the tank. You will be able to tell by looking for “glitter lines� that pass through the glass and land on the floor or walls of your room.

For total internal reflection (TIR), the light entering the water must strike the surface at an angle less than 60 degrees from vertical. Measure the length of your aquarium, divide by 4, and mount your light at least that height or higher over the center of the water’s surface. When the light strikes the water, it will be bent to less than 41 degrees from vertical (Snell’s Law). It will then strike the glass or acylic at an angle that reflects it back into your tank.

[Chihuahua6]

Great points again. With my tank the minimum distance would need to be 5". The only thing about the lighting is this is not going to be a typical mixed reef. There will be a few select species all from shallow water, bright light areas. Anything toward the bottom will also need adequate lighting especially if it is partially shaded although I am trying to avoid shading any of them.

[The Grim Reefer]

You're going to have a hard time not shading stuff down low. On a 30" tall you really need a good 250 HQI. The 150's just don't pack much of a punch. I had 150's sitting right on the top of my 125 which was only 23" tall and I only got PAR in the high 90's at the bottom.

[pjf]

A small hood that doesn’t accommodate supplemental lights often forces you to depend on your main MH light for viewing. If that is the case, aim to acclimate your corals to a 10-12 hour photoperiod with your main light.

In nature, the sun moves across the sky to reach into areas shaded during mid-day. Shaded corals depend on solar movement, not “punch.� In large aquaria, actinic tubes can reach into areas shaded from the main lights. In small aquaria, both right and left walls can reflect light to areas shaded from direct light. Do keep these surfaces and your MH shield clean.

Remember that water flow is more important than light intensity (previous link). I wonder if the “glitter� produced by that flow would help bring light to the recesses of your aquarium.

Good luck, Chihauhau6!

[pjf]

There is some additional information about 150-watt versus 250-watt HQI lighting in the Advanced Topics forum. The thread is “Light Intensity & Effectiveness. Experts please� and is located at the following link:

http://www.reefcentral.com/forums/sh...hreadid=975037

One contributor to that thread states that SPS corals near the surface will be photo-inhibited by the 250-watt HQI over a long photoperiod and suggests dimmer lighting.

The problem with deep tanks is that a single overhead MH light may photo inhibit the corals near the top while starving corals near the bottom. There are different ways to solve this problem. My “two-cents� for tall narrow tanks is to:

(1) Aim for a long viewing photoperiod if there is no room for supplemental lighting
(2) Obtain the strongest light that will avoid photo-inhibiting the corals at the top
(3) Depend on reflection to get light to the bottom
(4) Ensure adequate water flow, water quality and water temperature.

[The Grim Reefer]

Noon time sun exceeds 2000 UMOL's at the water surface on a clear summer day at a reef. You would have to mount even the best 250 watt HQI right at the water surface to match that intensity. Assuming you did that would the corals just under the surface of the water receive more light than they need? Yes, JUST LIKE THEY DO IN NATURE. The corals will also be subjectd to that light better than 12 hours a day.

The question to ask is will a 150 watt halide provide enough light for a brain coral on the sand of a 30" tall tank. Answer, no way in hell. I measured the PAR of 10K 150 watt halides running with PC actinics over my 125. The PAR sensor was 18.5" under the water surface directly below a lamp. Even with the fixture mounted 1" above the rim of the tank I only got PAR of 95 at the sandbed. That wasn't enough to keep a moderate light montipora digitala happy when it was sitting on a rock a few inches above the sand. Aint no way a brain coral on the sandbed of a 30" tall tank is going to have enough light to survive.

[pjf]

Originally posted by The Grim Reefer
Noon time sun exceeds 2000 UMOL's at the water surface on a clear summer day at a reef. You would have to mount even the best 250 watt HQI right at the water surface to match that intensity. Assuming you did that would the corals just under the surface of the water receive more light than they need? Yes, JUST LIKE THEY DO IN NATURE. The corals will also be subjectd to that light better than 12 hours a day.

The question to ask is will a 150 watt halide provide enough light for a brain coral on the sand of a 30" tall tank. Answer, no way in hell. I measured the PAR of 10K 150 watt halides running with PC actinics over my 125. The PAR sensor was 18.5" under the water surface directly below a lamp. Even with the fixture mounted 1" above the rim of the tank I only got PAR of 95 at the sandbed. That wasn't enough to keep a moderate light montipora digitala happy when it was sitting on a rock a few inches above the sand. Aint no way a brain coral on the sandbed of a 30" tall tank is going to have enough light to survive.

Grim Reefer,

Good points. What photoperiod is recommended for 250 HQI lighting? Under what circumstances can you photo-inhibit SPS corals near the surface with hood-mounted 250 HQI lighting?

Thanks!

[The Grim Reefer]

The trick is going to be placing the corals. Right now I am running T6 VHO flurescents and after about 6 hours my Frogspawn is hating life. I mounted it about halfway up the rocks, big screwup. The Acros and Montis up on top of the rocks are loving it.

Point is think about where you place the corals and watch what they are doing. In an nice halide/actinic system you can probably get away with 4 or 5 hours of halides a day. If corals are placed right 8 to 10 hours a day are not going to hurt them. Hard corals can exposed to the air at low tide many times, they are pretty adaptable to a lot of conditions. The ones they can least adapt to is poor water quality and lack of light.

[Chihuahua6]

Here's what I came up with. As per the recommendation of Sanjay and Eric Borneman I am going with the 250 watt HQI. Eric said 175 or 250 watt and Sanjay recommended 250. Without going into the why, what, photoperiod etc. the solution I have come up with I think will address both points mentioned by The Grim Reefer and pjf. (BTW do you guys have names?) ; )
I decided on the Icecap pendant and Icecap ballast for quality, long term reliability, future use (it can take a 250 or 400 watt bulb) and the fact that it's an electronic ballast which can take any bulb. In addition to the pendant I am going to try and install a PC strip with actinic bulbs and moonlights. Since I have 6" of room if I place the pendant slightly toward the front of the hood I think I may be able to build the PCs into the hood especially since the hood will be custom made by my husband. I will probably leave the top of the hood and/or the back open for ventilation and add fans on the sides. The top won't be seen anyway since the tank is so tall. I will just add a brace to hold the pendant and another to attach the PCs.
Now I can put the actinics on for a few hours. Then turn on the halides for up to six or seven hours a day (just guessing here). Then have just the actinics on for a few hours and have the moonlights come on for a few hours into the night for night viewing since I go to sleep around midnight. What do you think? Not bad for a chick huh?