lighting calculation for MH

[greenthumb]

Can anyone please advise me on the wattage for a 3ft x 3ft x 2.5ft (H)
tank. Should I use 1 MH or 2MH sets?

[vinz]

1 should be enough, but you should check the coverage of the light. It depends on the shape of the reflector.

Having 2 sets is suitable too.

You can also design your layout to take into account the light coverage or design the light configuration to fit your layout.

I'm sure you're already considering issues like budget, heat, etc.

[greenthumb]

Thanks Vinz, can you please help me with the MH wattage calculation required for this 3ft x 3ft x 2.5ft (H) tank because from the postings I have read on this forum, I am convince that the wattage calculation is different from those PL or FL.

[anzai]

most marine ppl agree that a normal mh hung about 1 ft above their tank would cover an area of about 2ft*2ft.

its a very general guideline for mh coverage area. of course the size of your pendant/reflector also plays a determining factor.

lastly the last i asked for 2.5ft depth, 250W of MH would be able to fully punch through the water to reach the bottom for high light requiremt plants and med light req corals ...

for my tank, its 2.5ft depth as well but im using 150W of MH. sadly my glosso is growing upwards. then again, maybe its the fertilisation ...

its your call really, 150W should be enough for crypts and other low light req plants.

[vinz]

There is no calculation involved here. You just need to consider the coverage you require. 150W is sufficient for a tank with a ht of 2ft. For 2.5 ft, I'm not sure.

If you want to play it safe, you can go for the 250W.

1 or 2, depends on your coverage needs.

In this case, I suppose a single 250W will reach deeper and hence you can hang it up higher to give you bigger light coverage.

[greenthumb]

Thanks for the advices, BTW do you guys know where to get any good MH? Price, brand of bulb and ballast etc.......? What should I look out for when purchasing MH, this is the first time that I am going to get MH for my next planted tank. Do you guys also have any recommendations for a 3ft x 3ft x 2.5ft (H) tank, thickness of glass, price, stand height, trustworthy tank makers?

Any comments will be very helpful to me as this is going to be quite a large project.

Thanks in advance!