Mh Lighting, How Much?

[xxBarneyxx]

There's pro's and cons to both MH and T5 lighting.

T5 Lighting
Pros:

• Units tend to be cheaper.
• More choice of colour temp on bulbs (and you can combine them to get just the right colour for your taste).
• They run cooler (no need for a chiller).
• They use less electric.
• Smaller and easier to build into your own hoods.
• Able to keep pretty much all soft corals and all the common LPS. Only able to keep a select few SPS and clams are probably a no-go as well.

Cons:

• Tubes are expensive and ideally need to be replaced every 6 months.
• Light penetration through water not as good as MH so in deeper tanks you can get quite a large drop off in usable PAR at the bottom of the tank.
• "Limits" you to LPS and softies (if you can call that "limited", personally I prefer most softies and LPS to SPS corals anyway).

MH Lighting
Pros:

• Tubes do not need to be replaced as often which can save a fair amount of cash over time.
• Much better light penetration through water giving you much better PAR throughout the tank.
• With the right MH lights you can keep pretty much anything (at least with regards to lights, other parameters of course will need to be met).

Cons:

• Uses more electric then T5 (though offset slightly by the lower price of tubes).
• Less choice of colour temps, often have to supplement with T5 to get a nice colour.
• Get very hot, can cause tank to overheat and will at a minimum require you to top up more (additional cost of RO water if you are on meter or buy it). If its really bad may require a chiller (additional equipment and electric costs).
• Much more bulky than T5's and with the heating issue too can be more difficult to build into a hood.

I have been thinking about going for MH units but to be honest I'm not overly fussed about SPS corals so I cant justify it (especially as I already have good T5 units). I'm probably going to leave it a year or two and wait to see what happens with LED units (and then hopefully be able to get the best of both worlds ).

 

[VictorMeldrew]

Fantastic thanks for that Barney

 

[ben1987]

couldnt you maybe use one MH in the middle and then some T5's for the side bits. then you get the best of both?

 

[VictorMeldrew]

That could work could'nt it, have you seen many people do that?

 

[SkiFletch]

You COULD use a T5/halide combo like that, but then you've got 8 T5 lamps and one halide. The system becomes complicated and expensive to replace bulbs then... And matching color temps would be a real pain.

Lets back up a little bit here. Vic, you've got a really long tank, but it's not too deep. That's what, 6 feet right? Do you have any cross braces across the top? And if so, where are they? Cause that might determin whether it's even possible to use halides...

 

[garybuk]

You COULD use a T5/halide combo like that, but then you've got 8 T5 lamps and one halide. The system becomes complicated and expensive to replace bulbs then... And matching color temps would be a real pain.

Lets back up a little bit here. Vic, you've got a really long tank, but it's not too deep. That's what, 6 feet right? Do you have any cross braces across the top? And if so, where are they? Cause that might determin whether it's even possible to use halides...

He has all round the side and one in the midddle

 

[VictorMeldrew]

Thanks Gary

 

[garybuk]

Thanks Gary

No probs i had/have the same tank , going to wast tho

 

[SkiFletch]

Sorry for the delayed reply VM.

With that setup, the ideal halide use would be 3x150 watt. A halide covers "relatively" a 2x2' surface area of a tank. So with a 6' long one, you'd want 3 units equidistant from each other... However, with a center brace, that's not going to work as the brace will cast a shadow and it'll just look horrible.

So you basically have 3 opitons: Make two cross braces for the top 2' from either side wall and remove the center one; Get a pair of 400 watt halides, string them up pretty high over the tank, have a lot of light spill, but cover the area (400's can handle a 3' square); Or go with individually reflected T5's staggered.

If it were my tank, I'd do the first option. Having cross-braces made for you should be really simple, and securing them with silicone should be a snap. If you're not comfortable with that though, go with T5 tubes, stagger them with two coming from the left edge and two coming from the right edge and just make sure to stick to low-light corals on the edges. Rocscaping with holes on the sides would also do well.

 

[VictorMeldrew]

Hi Ski

Thanks alot mate, you just made up my mind, I am not going to go for halides with this tank. To be honest mate I priced them up this weekend and was gobsmacked when I they told me how much they were. I see what you are saying about the brace aswell, thanks for mentioning that, i do not think i would have took that into consideration. So it looks like i might be going for T5 now.

Thanks
VM

 

[SkiFletch]

Good call VM

Just keep the low-light corals on the sides and keep the side-walls free of rock to remove the temptation for putting corals there

 

[VictorMeldrew]

I hear you mate, good advice thanks

 

[goonerman1]

I don't really understand why people keep saying that Halides cost more to run than T5's???

Surely if you are running 150 watts of halide or 150 watts of T5's you are still running 150 watts?? and therefor the cost of running them would equal exactly the same

 

[xxBarneyxx]

Both might be putting out 150W of light but the method by which they do it is very different.

Not going into too much detail but in short a MH is not as energy efficient. For example a MH might need to use 300w of power to create 150W of light output while a T5 would only use 200w of power to give 150w (numbers made up so probably not that extreme).

 

[goonerman1]

Both might be putting out 150W of light but the method by which they do it is very different.

Not going into too much detail but in short a MH is not as energy efficient. For example a MH might need to use 300w of power to create 150W of light output while a T5 would only use 200w of power to give 150w (numbers made up so probably not that extreme).

Ahhhhhhh........ I see