What SPS are the most light demanding?
- Thread starter acroholic
- Start date
What kind of light do you have on your frag tank?
I have two 70 watt HQI metal halides with Ushio 20K bulbs. The HQIs are retrofits with electronic ballasts and UV glass. I have it housed in a fan cooled fixture.
My idea is that the light is much more even with two 70 watt HQI lights vs a single 150 watt in the center. I don't want shaded areas on the left and right side of the tank.
I have had people tell me I need 2 x 150 watt pendants on this thing, and my gosh, the tank is a standard 20 gallon long, 30" long x 12" wide x 12" deep. 18 net gallons. I have the two halides in the exact center of the left and right halves of the tank. From the bulb to the bottom glass is about 13.5", so there is very little penetration needed.
Each 70 watt halide only has to light up 9 gallons of water at a depth of no more than 12-13 inches.
My main tank is a 120 with 716 watts of HQI/actinic and grows acros at depths of up to 22" from the bulbs.
Am I wrong thinking that two 70 watt HQIs will be great? One single 150 watt HQI is too much light in one spot for a 20L IMO, and two is way overkill.
I have 6 watts per gallon in the 120. This 20 will have 7 per gallon. I know the WPG rule is not the best, but I have a hard time seeing this small 18 gallon , 12 inch deep tank needing anything more than this.
Opinions?
I have frag of Miyagi Tort that is growing well in my 120. I suppose I could frag off a small piece and see how it does in the frag tank. I also have Oregon, California, and Sean Bennett Tort, but they are too small to cut right now.
I don't have a lot of sizeable corals yet, but would like to frag and sell some LEs at reasonable prices to other ARC members in the future.
Dave
Ditto on the Torts have high light requirements. Krep in mind that some of these LE farmers are growing SPS in not too deep tanks with 400 watts.
I think the 70 is a light "lite" expecially with a 20K lamps. If I where doing it I would have at least a 150 on it if not a 250 with some fans to keep it cool. If you do a single 150 you can put the higher demanding SPS under it and move the lower light ones off to the side. Not all LE SPS require high light but the majority do.
I think the 70 is a light "lite" expecially with a 20K lamps. If I where doing it I would have at least a 150 on it if not a 250 with some fans to keep it cool. If you do a single 150 you can put the higher demanding SPS under it and move the lower light ones off to the side. Not all LE SPS require high light but the majority do.
More even, yes, but more light? No. Light sources are not cumulative. I can't explain the physics behind it, but two light bulbs does not equal the amount of light from a single bulb that's twice as powerful. IMO, you'd be better off with the 150w (or even 175w).
Number of gallons doesn't matter, and bulb type really doesn't matter. Test your PAR in the main tank and see how that translates. Anything else is speculation.
This is the best way to measure it - only by penetration depth. It doesn't matter if you have a 6,000g frag tank - if it's 13.5" tall, it's 13.5" tall, and thus the light has the same penetration underneath it.
For reference, I have two 1000w's over my main tank. I get around 350 PAR at the corals, but only go down to 250 at 26" deep - the single bright light source penetrates extremely deep. On my 14" frag tank, I have a 175w 15Kk Iwasaki bulb in a LumenBright mini reflector - possibly the best low-wattage 15Kk setup known, and I get 250PAR at the corals (about 5" down). My point? The only way I know what my equivalent light levels are is to measure with a PAR meter.
Thanks for all the input everyone. I guess the only way to see if it works is to try it out for a while. It seems pretty bright right now as it is. I'm going to frag my myagi tort and set it up and see how it does. I have a frag in the 20 from a Salt Water City acro colony I bought, and also a frag (thanks Sal) from a coral SWC had listed as a "plasmacropora," which I have never heard of. Nice neon green. I thought it was a hydnophora, but whatever.
I'm already into it for the cost of the retros, bulbs, etc, so I want to give it a chance before I change anything. I don't need fast growth, just growth. I'll report back on how it goes.
Dave
I'm already into it for the cost of the retros, bulbs, etc, so I want to give it a chance before I change anything. I don't need fast growth, just growth. I'll report back on how it goes.
Dave
Right there with you. It is not stand alone, and is plumbed into my 120's MRC sump. It gets all the benefits of the skimmer/calcium reactor/kalk stirrer. Return is a Mag 3. If I couldn't have done it that way I would have just used my 120, but I don't like the look of frag discs everywhere in the show tank.
This 20 Long has a center overflow (3 sided acrylic), and a hole in each back upper left and right corner for a 1/2" bulkhead return. Looks like a mini-me version of my 120 Tech series.
This 20 Long has a center overflow (3 sided acrylic), and a hole in each back upper left and right corner for a 1/2" bulkhead return. Looks like a mini-me version of my 120 Tech series.
- Messages
- 4,441
- Reaction score
- 1,330
I think acros in general are simply more light demanding than any monti. I found that some don't care for a lot of light though such as the pink jade and pink lemonade. I've moved mine to lower light areas and I've noticed increased growth and color. I agree with Sprayin that torts don't seem to have an upper limit on light. The stronger the better.
