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New Setup lighting requirements

spill50

Member
Joined
19 Jan 2010
Messages
211
Location
Beverley, UK
Hi all,

Just after a bit of advice really on lighting requirements for my new setup. I'll start with my current setup.

Tank: 36"x15"x15" 120L
CO2: Pressurised (Fire extinguisher) on 3 hours before lights on
Lighting: Arcadia Twin 39w controller (1x Original Tropical, 1x Plant Pro tubes) on 6 hours/day, about 5cm from water surface in the tank hood with reflectors.
Ferts: dosing 15ml/day (APF All in One Plant Nutrition)
Planting: medium to heavy

So I'm upgrading my tank to an optiwhite, rimless/brace-less 48"x16"x16" I've nearly finished building my new cabinet (just need to finish painting it) and want to start looking at building a diy luminaire. I would like to use my existing twin 39w controller but I'm not quite sure if I need to add more light and how far away I should hang the luminaire from the water surface.

Obviously if I stick with the twin 39w they will be a fair bit further away from the water, plus the extra inch of water. I assume there would be less light getting to the bottom of the tank.

So would I need extra light to compensate for the extra height and how much extra? Also what sort of hanging height should I be looking at? So I can work out how high my brackets need to be.

I've attached some drawings to show what I'm thinking of with some possible lighting configurations. Hope fully they are pretty self explanatory.

7573745332_aa55c74f87_b.jpg


Thanks,

Richard
 
Hello,
People who worry about needing extra light for penetration are the ones that most often post "help me" threads in the Algae forum. You should be more concerned about CO2 penetration, not light penetration, because CO2 grows healthy plants. Light just makes them grow faster, not necessarily healthier.

Cheers,
 
So your suggesting just stick with the 2x 39w T5s then. Which would only give me 1.7 watts per gallon. I understand that more light will give faster uptake but with so much contradicting advice out there it's difficult to know what to ignore. I don't have as much experience with this stuff as some of you guys, which is why I asked here.
 
Hi,
spill50 said:
So your suggesting just stick with the 2x 39w T5s then. Which would only give me 1.7 watts per gallon. I understand that more light will give faster uptake but with so much contradicting advice out there it's difficult to know what to ignore. I don't have as much experience with this stuff as some of you guys, which is why I asked here.
Hi there,
as Clive suggests its much easier to start with low lighting and hone in the co2 to get healthy, but slightly slower growing plants first rather than add lots of light and really struggle with c02 and heighten the risk of algae problems. I run my current 180l set up on approx 1.7wpg and am having good growth (see here if interested: viewtopic.php?f=35&t=17929&start=200). One thing, i can see your previous set up was 36" and your new one 48" long, i would personally go for 2x t5 ho with reflectors but with bulbs to suit the length of your tank (ie as close to the tank length as possible), whichever wattage these may be. This will minimise the light intensity drop off at the ends of the tank. If your planning on suspending lighting from above then you can control intensity with the height you set the luminaire above the water surface, start high, and lower if and when necessary :thumbup: If you want to full proof the lighting system from the outset you could add 3x t5 to your unit with individual controllers for versatility, but really most suggest that 2x appropriate sized t5 ho with reflectors can provide enough light to grow most plants :thumbup: ....its then just about getting the the c02 and distribution spot on :rolleyes:
Good luck with the new project, sounds very exciting.
Cheerio,
Ady.
 
That makes total sense, the falloff at the ends of the tank was one of my concerns, hence the staggered and full length options.

I think what I'll do is go for the twin 54w option which is the full width of the tank but make it wide enough to add more tubes in the future if I need them.

Just had a look at your tank, it looks amazing.

Thanks,

Richard
 
Hi, no problem and thanks for the nice comment.
Another thing ive noticed was you suggested 1.7wpg for the big tank on 2 x 39w. I would think the volume of that tank would be higher than 47 us gallons, maybe nearer 50 so that seems like a high calculation given its 4 foot length, ensure when your working on the wpg rule that your calculating with us gallons not uk gallons :thumbup: I would think the 78w would be giving more like 1.5wpg, and on the suggested 2x 54w youd be getting nearer 2 wpg which will be good, especially given that you can raise/lower the lighting above water surface to suit.
Nowadays people tend to use par levels to determine lighting intensity rather than wpg, but par meters cost around £200 so wpg suffices for most as a guide!
Cheerio,
Ady.
 
Yeah that's my bad I was using imperial gallons, doh! It works out to just under 53 US gallons so yeah would be around 2 w/g.

I actually have a Seneye Reef which I'm planning on installing into the new tank which has built in PAR, LUX and Kelvin meters, which should be very handy when adjusting the height of the lights.

Thanks again for the advice.
 
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