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Lighting question

1K views 5 replies 4 participants last post by  Ladipyg 
#1 ·
I've got a 60 gallon tank that is 21" deep that I'm building a custom hood for.
The plan is for the coveted lush planted freshwater tank with the option of going to a reef setup in the future-meaning, I don't want to buy light fixtures just to replace them 3-5 years down the road. :shock:

I've found a fixture that uses compact florescents and holds 2 96watt bulbs which I can get in just about any spectrum I want. And it would be easy for me to add another fixture to hold an additional (or two) 96 watt bulb(s) when (or if) I eventually go to a reef setup. But I'm not entirely convinced that reef is for me.

Because of the size of the tank (36"x18"), I think I need at least two bulbs in order to prevent dark corners. The next size down would be 55 watt bulbs and I think I'll have to toss them for a reef setup which seems wasteful. And I'd rather not have dozens of bulbs under the hood.
I think the 96 watt bulbs would work out to be the best but wanted opinions. Is 192 watts total going to cause the algae takeover from hell you think? Or a better question might be, any recommendations on preventing it?
I'm planning on CO2 because of the amount of light. I don't think it'd be balanced otherwise. And I'd rather the plants grow faster.

I didn't want to do VHO because of the expense and how fast the bulbs burn out. Nor did I want to do metal halide because of expense and heat.

As for my level of experience if helpful, I've had 30 gallon tropical fish tank for over 10 years. I started live plants in a 5 gallon beta tank about a year or so ago because of algae (I was stubborn about where I wanted the tank which is close to a window). I used live plants in it because in three days, the entire tank would turn green. Since adding plants, I barely get any algae. No CO2, or ferts, or special substrate really. Just gentle filtration, some snails and a beta keep an amazon sword and two anubias happy. That's been my experience thus far so I could easily get in over my head. :lol:

Thanks in advance.
 
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#2 ·
Hello & Welcome to the forum.

If you're planning on building your own hood anyway; whether you wanna go freshwater or saltwater there, now or later, I'd personally built it housing normal T8 flourecent bulbs, I'd built it to house 2-3 the length of the tank for freshwater (thou I'm not sure if the same was to apply for saltwater) that stretching across the whole tank will allow you to exchange bulbs any time you decide to go a different route with the tank.
 
#3 ·
I know nothing whatever about reef tanks and the required lighting, and as your intention is likely to be in that direction I'll just make some observations that may be useful in avoiding problems in the interim with plants.

Your previous planted tank experience was low-tech, and you have seen how well that works. That is the basis of my approach and Angel's too. Once you get into higher light, you are correct that nutrients--carbon from CO2, nitrogen [ammonium] and minerals--will have to be increased to balance. Plants will grow up to the limiting factor, meaning the nutrient (or light) which is inadequate in balance with the rest. Then algae takes over.

Fish and biological processes produce a considerable amount of CO2, and the plants obviously use it. In my aquaria, I have diurnal pH shifts of .4, in other words from a pH of 6.0 at dawn to 6.4 and sometimes 6.5 in the evening. This is caused by the plants. As they use CO2 during daylight in photosynthesis, it removes carbonates from the water and the pH rises. During the darkness the fish and plants continue to release CO2 and the carbonates return and the pH falls. This diurnal variation occurs in all aquaria, and in nature, and fish have no problems because it is relatively minimal.

When you add diffused CO2, this variation can become very great, and that is a problem. Shutting off the CO2 at night is the usual remedy, since plants cannot use it in darkness so it is wasted as well as causing problems for the fish. The minerals and nitrogen required to balance the added CO2 are not insignificant in themselves. Takashi Amano, the "inventor" of those beautiful "Nature Aquaria", writes of daily fertilization of various minerals in sizable dosages to balance the CO2, and of course the light has to be more intense.

My suggestion would be to build the hood to house the number of tubes for the proposed reef tank, but wire them so only half can be on. Then select good full spectrum tubes and have those working with the additional tubes missing. I mentioned the wiring because in store-bought fixtures they are wired so that all tubes must be on; if one is taken out the others won't light, and I gather this is due to the wiring and ballast. If you can do this, you will be able to use only a couple of tubes and you can forget about CO2 and more fertilizers. Just a thought, given your past success with this approach.

Byron.
 
#4 ·
Thanks for the advice. :D I would like to keep it low tech, but I think with the amount of light I'll need to have CO2 or else I can count on algae.

My next question concerns the filter and CO2 and O2. My experience is with the type of filter that hangs on the back. This 60 gallon will have a canister filter. I'm having trouble figuring out what type/how much/if there should be surface agitation. I understand you lose CO2 with it. But the fish need O2.

How do I know what level of surface agitation is optimal? I'm not even sure of the minimum amount of agitation required for any gas exchange. Does it need to just ripple a little?
 
#5 ·
Thanks for the advice. :D I would like to keep it low tech, but I think with the amount of light I'll need to have CO2 or else I can count on algae.

My next question concerns the filter and CO2 and O2. My experience is with the type of filter that hangs on the back. This 60 gallon will have a canister filter. I'm having trouble figuring out what type/how much/if there should be surface agitation. I understand you lose CO2 with it. But the fish need O2.

How do I know what level of surface agitation is optimal? I'm not even sure of the minimum amount of agitation required for any gas exchange. Does it need to just ripple a little?
This will be less of an issue if you go with CO2 diffusion. In a low-tech natural planted tank, it is very critical to keep water movement and surface disturbance at an absolute minimum for the needs of the fish and plants. I explain this fully in the section on filtration in Part Three of my 4-part series of stickies at the head of this section, so won't repeat that here.

The issue of oxygen in the planted aquarium is frequently over-stated. During daylight plants produce far more than they and the fish and bacteria can use--and bacteria by the way is the largest user of oxygen in the aquarium by far--and while during darkness all these organisms (fish, bacteria and plants) are using oxygen, unless the aquarium is overstocked beyond the capability of the biological balance there will not be a shortage. Some authorities recommend surface disturbance only during the darkness to ensure oxygen is freely available during night; I have a lot of fish in my aquaria, and the canister filters do create minimal surface disturbance, so I'm probably covered.

I really would try to control the light over a planted tank. Aside from the plant- and algae-related issues, there are the fish. Most of these we keep in such aquaria come from dimly-lit waters and are not "happy" with bright lighting. Floating plants help, but I prefer to keep the lighting minimal from the start. I've commented in other threads on some of my experiences with fish and light and what this tells us. It is something not to be lightly dismissed, as it concerns the health of our fish.

Byron.
 
#6 ·
Just a small point...2 years is way beyond the life of a CF bulb...you would have to replace them for a salt water set up anyhow down the road. Why not try T-5's, they don't heat up as much and give great coverage. The amount of heat given off by the bulbs will be a big factor when you start a saltwater tank...they have to be kept below 80 degrees if you are going to do corals later.
 
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