Is 150 x 2 watts MH lights too much for a 5" x 2"

[roy]

Just want to make sure before placing the order. Also, is MH lights REALLY necessary, i.e. overkill? I'm opting for MH because I can't find any 5' lights with sufficient wattage.

Thanks,
Roy

[David]

hi roy

dont worry it would not be over kill...infact it may just be alittle underrated for a tank of your size depending on the type of plants you intend to keep. Due to the continuous intensity that the MH can give during its estimated service life of 2 to 2.5 years, your running cost will be much lower when it comes to bulb replacement.

in fact i have just ordered my 2x150watts for my 4x1.5x2 feet tank[]

[roy]

Where did you order your MH lights? Does it look good and cheaper than $195 as sold in Balestier?

The unit I saw is a little bulky - 13" diameter at the base, 13" high and 43" long with the chain. It looks okay and a little industrial looking.

Would appreciate if you revert with info of the MH you ordered.

Thanks,
Roy

[vinz]

Hmmm.... The advantage of MH over PL and FL is ability to penetrate the water. It also has a spot effect. Technically, you could use just 1. All the bright plants just has to be directly under the brightest spot, at the peripherals, the low light plants. Using 2 just means you have 2 highlight spots.

For those who have used MH, does the above make sense? How many watts do you need for a single MH bulb to penetrate 2 feet of water?

[roy]

Vinz, for a moment I thought you're using MH lights but the last paragraph kinda threw me off []

Well, I'm no expert on lighting and none whatsoever on MH lights but judging by what I've seen in certain LFS and in the lights showroom, I'm quite sure one MH blub will easily penetrate 2-3' of water and more blubs for lights distribution.

Cheers,
Roy

[loupgarou]

I'm using a single mh for a 4ft tank. being that way, its sufficient, however, if I arrange it wrongly, all the tall plants will cast a shadow at the corners.. (in anycase, I keep crypts at the corner...hehe)

mh can easily penetrate 3ft (and if you check the wisma fish tank, probably 10ft.)

[vinz]

What I meant is that there are different wattage of MH bulbs. 150 watts probably does a great job penetrating water... what about, say, a single 75 watt bulb? (I'm not familiar with MH wattage... just quoting what I remember from MH threads which I do not pay a lot of attention to).

Perhaps, we shouldn't be using 3W/Gal guideline for MH lights. We should be stating how many watts in a single bulb needed to penetrate how much water. Number of lights depend on the length of the tank and the layout of the tank.

[David]

hi vinz...

for MH the range that is mostly used in aquarium is 70watts and 150watts. due to the marginal cost difference between the two...the 150watts is more popular...the 3W/gallon rule somehow does not apply as the intensity is very different from PL or FL.

Lou is correct and that plant arrangement has to be thought of carefully as MH cast very hard shadows......

Roy the one that i ordered is from bioplast...that is the one with the 2 PL tube in the center which actually is for marine tank....but i take it as plant maintnence light[]

[roy]

Wow, the MH from Bioplast is REALLY nice! Looks like one of those battle cruiser from Star Wars. It's very expensive though. Don't know what price you were quoted but the unit was quoted to me at $1,200.

Cheers,
Roy

[roy]

Vinz, the showroom demo-ed the 70 watts MH unit. All I can say it's glaring to the point of blinding! The 70 watts spec is deceiving because it generates more lights than your typical PL lights.

Cheers,
Roy

[sherchoo]

Roy,
If you look at the PL light it would be juz as blinding as the MH.

Anyway, your question whether 2X150W MH is too much, I would say it may just enough or not enough depending on the plants your inteding to grow. I'm using 2X150W for my 4X2X2 and it seems not too much as the algae is under control. Most plants are doing fine while some are suffering from nutrient deficiency which I hope to work out soon before leaving overseas again.

But, other forumers may beg to differ as I know someone that is using 4X70W MH and his 5X2X2 tank is doing fine (last I heard). Kingpin, maybe you can comment on this.

[roy]

Actually, I was prepared to live with my 1.9 watts per gallon PL lights. At this level of illumination, the tank looks bright but, like a forumer was saying, once the plants start growig than 1.9 wpg may not be enough. Was looking for an additional PL unit but can't find any.

Furthermore, I'll be travelling for work soon and who knows when I would get the chance to tweak my tank so might as well take the MH plunge.

Cheers,
Roy

[william quek]

Just for your info, OSRAM a German bulb manufacturer has a 150 watt(5200K, 11000 lumen)daylight metal halide double ended and they have incoporated UV stop (prevent UV by using certain type of glass as the bulb). Cost is about $32 per bulb, might increase very soon as the EUROS dollar is gaining strength. About EUROS, I think EHIEM has increase its pricing due to the EUROS and likewise for all european products. Interested leave your contact no. and I will get back to you where U can purchase it

[sherchoo]

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On 1/1/2003 1:08:57 PM

Just for your info, OSRAM a German bulb manufacturer has a 150 watt(5200K, 11000 lumen)daylight metal halide double ended and they have incoporated UV stop (prevent UV by using certain type of glass as the bulb).
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William,
I'm using Osram 150W 6500K daylight MH bulbs. The Iwasaki D.ended wasn't available so the supplier offered this instead.

[roy]

Will, you've got PM.

[kingpin]

My 5 feet is doing fine with 4x70W. I had to adjust the lights higher to prevent spot algae from covering the glosso leaves. The thing about using 2x150W is the coverage of the tank might not be good. You will be sacificing illumination for coverage when adjusting the lights higher. 3x150W will be good. Each light covers 2ft with some overlap. Can also use back the same lights if you decided to upgrade to a 6 feet later[].