I dont under stand what T5s or T8s are, and why they are different to ordinary fluero tubes. What is a metal halide and why are they so much better and expensive?

What is the difference between these and how do you know the sizes for them?

http://www.petplanet.co.nz/shopping/pgm ... d=354&=SID

http://www.petplanet.co.nz/shopping/pgm ... d=291&=SID

What bulbs can go in what? like can T5s go in ordinary fitting if the volts are the same or do the watts have to be as well?

And what relevence to watts have to the actual amount of light that gets to your tank?

Sorry but I fail to understand lighting and I finally bothered to ask.

Also I posted in here rather than saltwater or techical beacause plant peopletend to know this stuff. Would I be better off posting some where else?

I don't get lighting very well either

T5 and T8 refer to the thickness of the bulb. T5 is 5/8ths of an inch thick, T8s are 8/8ths of an inch thick (ie 1 inch). T5s are brighter because the bulb is much thinner so more light can pass through the bulb than the T8. Metal halides produce far more light, typically coming in 150W, 250W and 400W bulbs, they also produce far more heat so you can not enclose them in a canopy.

your light fitting will need to be specific to a T5 connection, ie you can not put a T5 bulb in a T8 fitting and vice versa, also you would need to be ensure that the ballast is rated for the wattage of your bulb. The amount of light you need depends on your application, from memory i think a marine reef tank would need around 1-2 watts per litre, fish only tank (fresh or salt) whatever you prefer, and planted tank you would need to check with someone else.. Also more important if you are keeping plants, or a reef aquarium is the K value of the bulb, you will need a particular kelvin rating for plants, around the 6500K mark, for reefs its anywhere between around 10,000 and 20,000K or a combination of both

T5 and T8 are a measurement. Indicating that the tube is 5/8th of an inch, or 8/8 = 1 inch diameter.

HTH

Extract from wiki

"Lamps are typically identified by a code such as F##T##, where F is for fluorescent, the first number indicates the power in watts (or strangely, length in inches in very long lamps), the T indicates that the shape of the bulb is tubular, and the last number is diameter in eighths of an inch. Typical diameters are T12 (1½" or 38 mm) for residential bulbs with old magnetic ballasts, T8 (1" or 25 mm) for commercial energy-saving lamps with electronic ballasts, and T5 (5⁄8" or 16 mm) for very small lamps which may even operate from a battery-powered device."

T5 tubes will not fit into a T8 fitting. T12 bulbs are not very efficient because of less surface area. T5 are the most efficient for light output per watt.

I currently use T8 tubes as they are the cheapest to replace.

HTH

you will need a particular kelvin rating for plants, around the 6500K mark

I justed checked my kelvin rating for my bulbs and it is only 2200 and they grow, If I added T5s for example would they take off in growth?

http://www.aquariumpros.com/articles/lamptypes.shtml

If you increase light, then the plants will be stimulated to grow more, therefore requiring more nutrients and carbon for photosynthesis. Carbon from Excel or CO2 inclusion. If you don't add the nutrients the plants may become stunted, or thin and wispy.

What is the difference between these and how do you know the sizes for them?

http://www.petplanet.co.nz/shopping/pgm ... d=354&=SID

http://www.petplanet.co.nz/shopping/pgm ... d=291&=SID

I still dont get this?

The first link is to a complete T5 system, which you can put T5 bulbs in, plug into the wall, and away you go. It sits atop your fish tank.

The second link is the bones of the previous system. It has no reflector, no housing, just a remote ballast which drives the tubes, and two sets of leads that run to end caps which go on the end of the actual T5 tube. It also has clips to hold the tubes if you need them.

To give you an idea of the real world difference, the first unit could go straight on top of your tank for light out of the box, once you put tubes in. The unit holds all the goodies which make the lights go.

The second one (which I have a couple of) has to be set up, you put the ballast wherever suits you, then run the cables to the light tubes, and sort out a reflector and mounting for the tubes. I use them in a tank which has a low profile hood, no room for a normal ballast or reflector system in it.

Hope that helps!