What constitutes as low/med/high light? - New to Planted Aquariums

Tedison · 08-02-2008, 10:22 AM

Hey everyone. I'm brand spanking new to planted tanks, although I have had the fish tank I am planting in for quite a while (about months). I got fed up of having all those cheap looking plastic plants and gaudy ornaments (you know the ones) in my tank, so I decided to start planting it. Of course being the impatient person I am I didn't do much research before buying lights, and I ended up getting a coralife 2 tube 36 watt T5 flourescent plant light for my 29 gallon tank. After doing some reading, I realized that I would need a bit more lighting than just that for my tank and I put my old 20 watt flourescent on top as well. Theres no CO2 applied yet, although I hope to make a DIY system one day soon.

Well, anyway, despite the long post I pretty much just have 2 questions...

Is 56 watts of flourescent lighting enough for my tank, or should i splurge a bit more and get more lighting? And if so, how much light would be enough for a nice planted set up?

bacod253 · 08-02-2008, 06:00 PM

It all depends on what you'd like to grow.

You have ballpark enough wattage to grow a fair number of things (java moss/fern, Hygrophilia, Water sprite, Bolbitis, riccia, the list goes on). When you add CO2 and Ferts the list expands even more. You should check out the plant finder http://aquaticplantcentral.com/forumapc/plantfinder/ and see what kind of plants you are looking for. You have moderate light with just the one T5 fixture imo.

trenac · 08-02-2008, 06:02 PM

If you have 56 watts over a 29G tank, that would be low light (1.93wpg). That is enough to grow low light plants, like: Anubias, mosses, crypts, horwort etc..

A 2 x 36 is 72 watts which would give you 2.48 wpg. This would be considered low-medium light setup. In this case you could grow a little more variety of plants.

Tedison · 08-03-2008, 09:18 AM

awesome thanks guys. thelight is 2x16 watt T-5 bulbs.. could I just replace the bulbs with higher wattage bulbs of the same size or would that not work?

gheitman · 08-03-2008, 09:49 AM

That would not work because the ballast in your fixture won't support the higher wattage. You probably can't change the ballast either because the Coralife T-5 fixtures aren't designed to let you do that AFAIK.

hoppycalif · 08-03-2008, 11:16 AM

Quote:

Originally Posted by trenac

If you have 56 watts over a 29G tank, that would be low light (1.93wpg). That is enough to grow low light plants, like: Anubias, mosses, crypts, horwort etc..

A 2 x 36 is 72 watts which would give you 2.48 wpg. This would be considered low-medium light setup. In this case you could grow a little more variety of plants.

I disagree. "High light" is the light intensity that lets you grow almost all of the typical aquatic plants, with possibly some problems with ground cover plants. "Low light" lets you grow anubias, mosses, cryptps, ferns, etc., but will not let you grow plants that demand lots of light. And, only Marsilea is likely to survive as carpet type plant.

For a typical shape tank, using PC lights with reflectors similar to AH Supply reflectors, 2 watts per gallon is borderline "high light", 1.3 or so is borderline "low light". Both cases are for lights that are around 2 inches above the water. Raise the lights and the numbers change drastically.

If the 56 watts are PC bulbs with good reflectors, you can grow most plants, so that is borderline "high light", not low-medium light. If the 56 watts are ordinary shop lights, with their white painted housing serving as a reflector, it is low light.

This is, of course, just my opinion and is subject to change as I learn more.

Tedison · 08-03-2008, 07:56 PM

well one light giving me 20 watts is just a regular shop light (the one that came with my tank) but the other 36 watts is supplied by a coralife T-5 ballast... this one to be exact

hoppycalif · 08-03-2008, 08:40 PM

The Coralife fixture doesn't seem to have the typical individual reflectors that T5 lights usually have, and the single reflector it seems to have doesn't look like it is anything special. Without seeing a better photo of it or seeing one of these in person I guess it is similar to an AH Supply reflector. If it had the individual reflectors many people find that type of T5 light gives as much light intensity as PC bulb fixtures having around 1.3 to 1.5 times as much wattage. This one probably is not that good. So I would count the 36 watts as good for 1.2 watts per gallon, and the shop light as good for maybe another .5 or so watts per gallon of PC bulbs, giving a total of around 1.7 watts per gallon PC AH Supply equivalent intensity. That would be low light intensity, as Trena said, in my opinion. CO2 always helps, even with low light intensity, but you don't absolutely have to use it.

Tedison · 08-04-2008, 11:33 AM

i'm happy with having a low light tank.. this i my first tank after all, and I do tend to dive into things head first. I just need to find a good ground cover and I think I will be alright!