Heavily Planted 2 Metre Tank Lighting

[Spiceweasel69]

Hi

Just about to get my 2 metre tank delivered and plan to go heavily planted. Its a 575 litre tank so at 3.5 WPG id need a total of around 450 Watts of lighting. I will be making this myself from t5 tubes. Just wondering if there were any recommended produsts / electronic ballast that i should go for above others.

Also, i can only get 5ft tubes in the 6'6" tank, so i will be offsetting every second tube by a foot or so so as the whole tank is lit effectiveley. Can anyone see a problem with this? By my reckoning, i will need 6 x 5ft tubes at 80W each to give 480Watts. One of the middle tubes will be running independently to come on before and shut off after the other 5 so as not to stress the fish with sudden light fluctuations. The tubes are 6500K but ill try to get a few 5500K / 6000K in there for good measure.

Can anyone see a problem with this setup? (except the algae issue which will be controlled by pressureised co2 and ferts).

Thanks

 

[lljdma06]

Unless you are going for some extremely fragile species, I don't think you'll need 3.5WPG. It's a big tank, honestly with pressurized CO2 and good lighting (T5s or Power compacts), you'll be fine with between 1-2WPG and you'll pretty much be able to grow what's available in the trade. Lighting doesn't work the same for larger systems, you end up needing less for the same results as say a 20g tank. That might save you a buck or two in the lighting department. How deep is the tank?

Hi

Just about to get my 2 metre tank delivered and plan to go heavily planted. Its a 575 litre tank so at 3.5 WPG id need a total of around 450 Watts of lighting. I will be making this myself from t5 tubes. Just wondering if there were any recommended produsts / electronic ballast that i should go for above others.

Also, i can only get 5ft tubes in the 6'6" tank, so i will be offsetting every second tube by a foot or so so as the whole tank is lit effectiveley. Can anyone see a problem with this? By my reckoning, i will need 6 x 5ft tubes at 80W each to give 480Watts. One of the middle tubes will be running independently to come on before and shut off after the other 5 so as not to stress the fish with sudden light fluctuations. The tubes are 6500K but ill try to get a few 5500K / 6000K in there for good measure.

Can anyone see a problem with this setup? (except the algae issue which will be controlled by pressureised co2 and ferts).

Thanks

 

[Spiceweasel69]

Hi

Thanks for reply. Tank is 70cm deep.

Iv never really believed in the wpg rule as i dont understand why depth of water is taken into consideration. As long as the water is well filtered and clear, at 60cm, 99% of light will get through. What should be taken into consideration is the surface area of the bottom of the tank versus the light output to give a W/m2 unit, which is how light is measured on the earths surface.

Anyhow, i appreciate that larger tanks may not need such a vast quantity of light. Got a credit note from Wilts, so the cost of parts isnt too much of an issue. Maybe will cut down to 4 tubes, still hitting 2WPG , 0r 295W/m2

 

[SuperColey1]

Like you I don't believe in the WPG rule at all. It doesn't apply to modern lighting which is much better than the old T12s that were used when this rule was calculated.

You would be surprised by the difference in light at the water surface to a substrate only 2 ft below it. Par readings can read 140 at the top and 50 at the bottom!!

There is a lot to figure into the equation other than wattage. The quality of reflector can make a huge difference. the angle of the reflector can make a huge difference.

250W over a tank but raised to get a better spread may have par readings of 110 at the top and 70 at the bottom whereas 150W unraised may read 140 at the top and 50 at the bottom.

Penetration is one aspect that we can't really go into unless we are about to start suggesting everybody gets quality PAR meters and for the price that isn't going to happen. lol

Add to this that T5 will penetrate much better than T8 due to the tubes narrow cirumference and normally better reflectors. LEDs are even better at penetrating.

As LLj says I do think 3.5WPG of T5 is overkill to say the least on this size tank. I would say 3.5WPG of T8 would be high light. For full scaping and carpeting at a turbo rate of growth you'll only need 2WPG of T5 or 3-4WPG of T8 maximum.

The more light you go for then the harder it will be to keep on top of circulation, CO2 and dosing. The larger the tank is the harder the circulation is to achieve anyway so I would say that going 3.5WPG of T5 would be asking for trouble!!!

AC

 

[Spiceweasel69]

Hmmm. Agreed.

Im gonna stick with 4.no 80W t5's, giving 320Watts for 130 Gallons, so around 2.5wpg.

With the colour temps and bearing in mind that im looking for 5ft tubes at high output, what are the best triphosphor bulbs to get?

Ta