Lighting Advice

[alanthomaswatson]

Hello all

I'm looking at setting up a new tank from scratch, as it's time to move up from my current small tank.

The installation is going into an old fireplace in the dining room. Access, power, bearing calcs etc etc have all been considered and I can make it work. The tank needs to be made to fit and will be 40" x 18" x 15".

I'm trying to figure out the best way to light the tank. As it's in the fireplace there's limited space above the tank for lighting so I think it rules out pendant fittings. I was looking at T8 units like Arcadia Ultraseal units.

Based on the size an volume of the unit, the calculator at petfish.net suggests I need:

Lighting requirements
Low light plants: 65.45 watts Low-medium light plants: 98.18 watts
Medium-bright light plants: 147.27 watts Bright light plants: 220.91 watts

The highest output Ultraseal is 58 watt. Does this mean I would need two 58w to get 116 watt lighting? I know this seems pretty simple but I've always had 'kit' aquariums and never had to think about lighting before. Is it this simple or is there some other way this is calculated?

Can anyone suggest any other way of lighting the tank?

Many thanks in advance

 

[waterdrop]

Yes, one simple way to start off thinking about the lighting you are talking about is to start off with your rough tank volume in US gallons (47G in your case) and say to yourself, ok, one T8 tube of 47 watts would give me 1 watt/gallon, 2 tubes (94 watts) would give 2 watts per gallon. I doubt you are planning to get into the separate hobby of a high-tech planted tank with a pressurized CO2 system (but if you are, just say so.) Two watts per gallon T8 is the rough breakpoint between the two approaches, "low-light" technique and "high-tech" approach.

In fact, in Aaron Norths nice "Back to Basics" article in our planted section, you can see that 1.0 to 1.5 watts/gallon is probably where you want to be for good "low-light" technique. This puts you at 70.5 watts T8 and that could be about 2 35w tubes or 3 24w tubes... anyway once you think about how much shorter the tube needs to be than your 40" tank length to accomodate the fixture that holds the tube, you can begin getting closer to figuring out wattages that work. Given types of fluorescents give off pretty fixed lighting amounts per inch or foot and so wattages available are fairly non-continuous, certainly not as flexible as incandescent (not that you'd want to use that!)

One disadvantage of a custom tank can come in if you don't give consideration to which standard lengths the lids, hoods, fluorescent fixtures and fluorescent bulbs come in. This can be a good factor to keep in mind when planning a custom tank as it can make things considerably easier.

~~waterdrop~~

 

[alanthomaswatson]

Thanks waterdrop, very useful

The reason I looked at the Arcadia's is that they have "universal mounting brackets for installation on aquarium hood or walls". Looking at the Arcadia website:

http/www.arcadia-uk.info/product.php?pid=47&mid=10&lan=en&sub=&id=4

it looks like these have plastic brackets but I can't figure out how these attach to the tank? Any ideas? Do these fix directly to the glass or do they need something to clip on to?

In response to your other points, the company who make the aquarium also make bespoke hoods. They're a little on the pricey side compared to standard units but I want to fill as much of the space with tank as I can.

As an aside, I've heard of people using two small heaters instead of one large one, so that there is always some heat if one packs in. Is there a size of aquarium at which this makes sense, or is it always a good idea?