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Discussion Starter · #1 ·
Hi all!

I'm planning on setting up my first planted tank. It's an old tank I'm rebuilding but I'm afraid the lighting is too low. It's approximately a 120 gallon tank (59" long, 20" wide, 23" high) and it has 2 T8 tubes (36Watt) which according to the manufacturer each give out 3350 lumen.

By all possible calculations I found on the internet, this is each time barely enough to grow something. I want a lot of plants, and nice looking ones but I want to avoid CO2 or Excel.

Is there any danger in starting with such low lights (i.e. algae all over the plants, or plants dying off), or is it safe to start but will there just be limited growth? Or am I better of just buying some extra lights from the start? From my calculations, I gather that I need at least another 12000 lumen, so that's a lot of lights! Is there any danger for algae if I do this? It would be a waste if I buy all these lights and have to turn them of due to algae.

Many thanks in advance!
 

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I am sure someone with more knowledge about large low-techs will come along. I just want to add that there is another factor that you need to consider when deciding on amount of light - it is duration of light. In a very low tech your main plant-grower are your lights. To succeed you need good quality lights that mimic sunlight and your algae control will come from photo period adjustments. It is a trial and error method which usually requires starting with at least adequate lighting for your tank. There are many measures of adequate and it depends on the quality of light, the size and depth of your tank etc. etc. I am not qualified to comment on that aspect. I am sure someone else will. Just keep in mind that light is your main asset and you need to control the how much and how long.
Good luck!
 

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It's a lot of watts, relatively speaking, but I think that's to power the length of the tubes.

My tank started with 1 T8, then went to two. Might be wise, if I'm on the right track, to consider new lighting.
 

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When I originally set up my 66 gallon planted tank 15 years ago, the canopy had four 40 watt T12 fluorescent bulbs. They were basically shop lights. I had more than twice what you have now, on a smaller tank (48"L x 16"W x 20"H). I could grow a lot of plants in it. So, you could keep what you have and add to it, or upgrade completely.
I would say that you need to either upgrade the lighting, or at least add to the lighting. There are a lot of choices out there now for lighting!
 

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Discussion Starter · #5 ·
So I guess I should really add some light!

I'm currently thinking about either getting two T5 54 watts that I can mount to the hood or a single LED bar. Both are approximately the same price, but as I already have lights, the LED bar would not be able to be centred while I can place a T5 on either side of the old T8's. Eventually I could also upgrade the T8 bar to a T5 one but that's if I still need more light, I don't like to replace things that are still working.

Any suggestion to the colour of the lights? I see Sumit suggests getting to close to Sunlight as possible. So ideally, I should just add two daylight tubes? Are the plant specific ones any good (the pink ones)?

Also I see the balance between photoperiod and amount of lights. Am I correct in thinking that I cannot make up for a small amount of lights by just increasing the photoperiod? As I currently understand, I need to start with a small photoperiod with 'intense' light instead of a large photoperiod with 'weak' light?
 

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You have two rows of T8 bulbs lighting the tank. That should give you around 40 PAR, which is enough to grow a lot of different plants. But, the 20 inch front to back depth of the tank means you won't have that much light over the whole substrate. If you just add another two rows of T8 bulbs, widely separated from the others, you would have uniform lighting, with enough intensity. You could stagger the bulbs so the ends of the tank get more light too.
 

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I put a T12 shop light over my 24" deep tank just to see what happened. In my CO2 injected tank plants pearled to 18" depth. Agree with Hoppy, buy another 4'x2 bulb fixture and you are good to go.

I'd use a long day, 10 hours at first and increase after a couple months once plants are settled down.

The intense and short day is for us idiots who buy a lot of light and want to use it. I really like the way my tank looks at 100% LED but can only use it for a short time at that level. Fish are happier in less light and their colors tend to look nicer as well. I am happier with my high powered LED that I run at 100% for an hour a day and much lower for the rest of the day than I was with the metal halide I could only run for 6-8 hours a day and suspect the fish are as well.
 

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I try and use 6700K light for planted tanks. But all 6700K are not equal. For example I have a Azoo Flexi Mini LED rated at 6700K. It can bring colours out like nothing else I have. The same plants under T5 6700K look bland in comparison.
My approach is to use high light and control algae by managing photo period and nutrient supply. In one tank I use 2 lights (covering different halves of the tank with large overlap area) - each work for 6 hours. One starts one hour earlier and the other ends one hour later - this works for me though I could have pushed growth with both on for 8 hours. But when I tried that algae became unmanageable. What I have now is well under the control of algae feeders. Just an example of light period management. What works for you will be different.
Cheers!
 
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