# 390 or 260 watts on a 90 gal?



## melonman (Oct 27, 2006)

I currently have 390 watts (a little over 4 per gallon) on my 90 gallon planted tank...I have been doing some reading lately and I became concerned that I might be overdoing it with my lighting setup. Would I be better of with 260 watts ( alittle less than 3 watts per gallon) or sticking with my 390. Any opinions will be greatly appreciated...thanks in advance yall


----------



## hoppycalif (Apr 7, 2005)

You will have fewer problems with algae now and in the future if you switch to about 200 watts. Even 260 watts is more than needed. However, if you raise those high wattage lights higher above the tank you can get the effect of having lower light intensity.


----------



## redstrat (Apr 3, 2006)

not to mention you might even get a better spread of light across the surface reducing dark corners.


----------



## TortoiseBoy (Dec 30, 2004)

How are your plants growing and how is your algae situation? What makes you think that you might be overdoing it besides the electric bill? 

If your 90 is like mine, you might have trouble with light penetration to the bottom of the tank if you reduce your light too much. I have 220 watts of light on my tank (4x55 watt bright kits from ahsupply.com, 2x9325K and 2x6700K) and I find that many of my plants grow quite "leggy." I think this may be due to the 27" height of the tank. Do you have trouble with this? 

My plants seem to do better when they get closer to the top. Is this not an indicator that I need more light? The cuttings that I have bought from people in the past have grown differently in my tank than they were growing in theirs, as well. I know that light is not the only potential difference but it is a key one 

I have actually been thinking about increasing my lighting to 330 watts, hoping to be able to get some better growth at the bottom of the tank. I am experimenting with glosso right now for the first time. I figure if I can grow it low to the substrate, my lighting is ok. 

Comments? I am especially interested in hearing what Hoppy has to say because of his comments about the 200 watts. Maybe I am doing something else wrong that is not related to lighting? 

Anyway, just thought I would chime in because I have the same tank size that you do and I have lighting now that is similar to what you were talking about trying. Good luck,

TB


----------



## Laith (Sep 4, 2004)

melonman said:


> I currently have 390 watts (a little over 4 per gallon) on my 90 gallon planted tank...I have been doing some reading lately and I became concerned that I might be overdoing it with my lighting setup. Would I be better of with 260 watts ( alittle less than 3 watts per gallon) or sticking with my 390. Any opinions will be greatly appreciated...thanks in advance yall


4+wpg is a bit high for my tastes. It's certainly doable: people have success with 5+ and 6+wpg but one *must* keep on top of things, especially adequate nutrient supply. Otherwise it can be a disaster waiting to happen.

Am I right in assuming that you can control separately some or all of the bulbs? If so, what I'd do with your setup is have 260w on for let's say eight or nine hours and in the middle of that period for about three hours use the full 390w. This is called the "noon burst" method and I've been using it for awhile and find it works well. However on my setups I have 1.4wpg for eight hours and 2.8wpg for five of those hours, all T5s (and glosso grew too well and I finally pulled it out as it required too much trimming, tanks between 20" and 24" deep).


----------



## melonman (Oct 27, 2006)

thanks for the replies guys!!! the main problem that i have been having is with a hairlike algae that forms around the edges of my broader leafed plants and looks more like a slime on finer leaves. I have a 3 130 watt lights that can be individually controlled...I gotta do something about this algae its driving me crazy


----------



## ringram (Jan 10, 2005)

Well, the standard 90g is 24", not 27". even still, it is a deep tank. I have the same tank and will be converting to a planted tank soon. My question is, how does Amano get such good growth on plants with his (generally) low lighting levels? My suspicion is that its not that the light is too low, but maybe something else. What kind of reflectors do you have? Are they clean? ferts and Co2 are in order, correct?


----------



## hoppycalif (Apr 7, 2005)

As I understand it, plants love light, even if it is 10 watts per gallon. But, so does algae. You can successfully grow almost all plants with 2 - 3 watts per gallon, assuming a tank that is of normal proportions and bigger than 15 -20 gallons, and you provide enough CO2 and fertilizers. But, the plants will grow slower, as will the algae. This is not bad. This is good. With super high light intensity, the plant growth is going to be fantastic, providing you can find a way to keep enough CO2 in the water and fertilize adequately. Unfortunately, the rapid plant growth is accompanied by at least equally rapid algae growth, once it starts up. And, your weekly gardening chores are going to become daily chores, just trying to keep the plants from over packing the tank. If you miss something during your gardening, the algae spores will very quickly start growing and in a matter of hours you will have an algae problem to deal with. Far better to have a plant growth rate that allows you a week to enjoy the tank, with only nominal gardening chores once a week. Plus, any algae that starts up will become visible and remain relatively limited in scope for long enough for you to attack it early and get rid of it. So, I can't see a good reason to want higher light intensity than 2 - 3 watts per gallon.


----------



## ruki (Jul 4, 2006)

I think the general rule is the more light you have, the more attention you have to pay to the tank to keep it from raising algae soup.

Medium light requires bi-monthly attention. Very high light requires daily attention.


----------

