Is this lighting/CO2 regimen ok?

[Yenko]

The lighting canopy for my new 70 gallon tank has 4X40w T12 tubes, primarily because the only waterproof endcaps avaliable in my area are T12 size, and I could only find good affordable ballasts in 2X40w.

So, now that I have 160W of light; I realize that I have quite a bit of light. I do not plan to use high CO2 levels (I will use one DIY CO2 bottle to help keep levels up) because I cannot afford even a conventional pressurized tank/needle valve setup at the moment; and a pH controller setup is well out of my price range.

Since I do not have a huge supply of avaliable CO2, I thought of a lighting plan based on part of the method Diana Walstad uses.

She has her tanks lit only dimly with artificial lighting, but situates them so they recieve sunlight for a few hours a day. Because I can independently control my ballasts (So I can choose between 80W and 160W of light), I decided on the following lighting system to approximate Diana Walstad's lighting regime (I'm aware 160W is less than tropical sunlight).

10 am: Ballast one goes on. (80w of light)

Noon: Ballast one goes off (0w of light); this is a complete rest period for CO2 levels to increase slightly.

2pm: Both ballasts switch on. (160w of light)

6 pm: Ballast one switches off. (80w of light)

10 pm. Ballast two switches off for the night.


OR:

10am: Both ballasts go on.

3pm: Both ballasts go off.

5pm: Both ballasts go on.

10 pm: Both ballasts go off.

 

[kenneth_kpe]

hmmm i remembered reading somewhere that plants might not benefit from short photoperiods of less then 4 hours i think ? im not sure who said this before and i have not researched much into it maybe its a good i dea to look into this more.. if im wrong then i guess its ok but i prefer the second lighting schedule but maybe with a 30 min headstart for the first ballast? before the second one so the fish dont suffer from er... "flash bang" syndrome hehe

 

[Yenko]

The short periods in the first schedule are not intended to actually grow plants - they are meant to simulate shade/diffuse sunlight like the plants would get most of the day in nature, and the high light period simulates the short period of direct sunlight that most plants get in nature.

 

[iggy01]

Good luck with that Yenko.

How close to the Walstad method do you intend to go? Will you be doing weekly water changes or will you be leaving it for months?

 

[Yenko]

I think I might do small weekly water changes; probably nothing in excess of 20 gallons weekly. The only fertilizer I plan to dose is KNO3 and when I can afford it CO2, and possibly K2SO4.

In the Diana Walstad system for fertilizers (fish waste only), Phosphorus builds up to high levels (Not dangerous to fish, but enough to grow alage). Alage in Walstad's tanks is prevented, in my opinon, by a combination of low supplies of other nutrients, a short photoperiod, limited CO2 and high levels of allelochemicals from plants, and she probably has a good snail population going on top of that.

In a 10 gallon tank with 46W of light, and CO2 dosed to roughly 20 ppm with a DIY supply, I had excellent plant growth and very little alage growth with no ferts and no water changes, but when I started dosing KNO3 to bump levels up to 10-15 ppm from 0-5 ppm, the alage growth did not increase while the plants grew much faster.

In my 32 gallon tank with no CO2 addition and only 40w of light, I grow duckweed on the surface, and cryptocorynes and Java Fern on the bottom. Alage growth is minimal, but bluegreen alage was growing slowly untill I added KNO3, which stopped it in it's tracks. Obviously, no alage or cyanobacteria is going to die because of an extra 10ppm of nitrates, but if the nitrates allow the uptake of more nutrients by plants then it's an effective anti-alage and fertilization solution.

In short, I belive KNO3 is the one fertilizer low-tech aquariums absolutely need for good macronutrient balance - with sufficient fish load all the other nutrients are supplied.

 

[kenneth_kpe]

you are planning to grow the tanks slowly right ? low maintenance tank ?

i see i see tell us how this goes for you good luck

 

[iggy01]

Best of luck, hope it all goes well for you.

Have you read this article , it may help you a bit also.