Halide Lighting Position On A 153x60x60 Tank

[Daniel Stevens]

I am new to marine fish keeping within the last 10 months, i have a tank approx 153x60x60 in dimensions and wish to check i have the lighting correctly timed and positioned.
I have many soft corals and also a clam and anenome, hermit crabs, starfish etc etc... To Date all of these are doing and well and i have lost NONE of my tank inhabitants (apart from the banded shrimp my dotty back ate).
The reason i write is i bought the basic set up as an established tank from a lady who fell on hard times.
Bit by bit i have replaced filters, power heads etc and have now started on my lighting, i have a 150w hanging metal halide set up with 2 x Downlights for night lighting, 2 x 150w 20'000k metal halides and 2 x 54w t5 actinic tubes 4FT in length.
I did not realise how poor the actinic tubes were until i replaced them, i have now ordered 2 x 150w 20'000k replacement metal halides that i purchased on Ebay brand new.
I have however conflicts of interest as to whether these are acceptable some saying i should purchase from a aquarium shop @ $200 a piece ( i paid $50) any suggestions or comments
Also how high should the light be positioned above the water and approx how many hours a day should they be on?

 

[WayneVT08]

I keep my MH's on for 10 hours a day for coral growth. Mine are also a 150w. It's all over a 30 US gallon tank. I keep my lights about 6-8 inches above the water.

 

[Colin_T]

the shop globes are generally the same globes as you would buy from anywhere else. The main thing is the Kelvin (K) rating. 20,000K are all pretty much the same regardless of where you get them from.

I wouldn't bother about actinics for extra blue light because the 20,000K M/H globes have heaps of blue light in them. In fact I don't actually like 20,000K M/H globes. I much prefer 10,000-14,000K globes. They give a much clearer light with less blue.

Normally you have the M/H lights 12-18inches above the tank. To see if your halides are high enough above the tank, have your lights on and put your hand just above the surface of the water. If you feel heat on your hand then the lights are too close and will warm the tank water.

You can have the lights on for up to 16 hours per day but most people only have them on for 8-10 hours per day. The longer the lights are on the more algae you will get.
Don't suddenly increase the lighting period because you can stress or kill the corals. If you want to increase the photo period then only increase it by 30-60 minutes per week.
If your corals are keeping their colours and not fading or going white, then they are getting sufficient light.

 

[Daniel Stevens]

Many thanks For your replies they are appreciated and comments taken on board.

 

[SkiFletch]

<---- confused. Those dimensions for the tank you listed, are those inches, centimeters, cubits? Important to know that

 

[Daniel Stevens]

<---- confused. Those dimensions for the tank you listed, are those inches, centimeters, cubits? Important to know that

The measurements are in cm's.... according to the aquarium calculator gives me 551litres, plus approx an additional 50-75 litres in the sump system.
Running a pump with a turnover of 12500 litres an hour and an additional fluval 4 pump in the tank at one end and a power head amongst the reef.

 

[Colin_T]

Those dimensions for the tank you listed, are those inches, centimeters, cubits? Important to know that

cubits, LOL
been a while since I last used them

 

[SkiFletch]

Ah, so we're talking a big tank here then

In the terms I'm familiar with, that's a 5x2x2' tank which is a standard 150gallon

For lighting it, you've got options, however using dual 150watt halides and just dual 54watt T5's will be some low light. Does the tank have any braces across the width of the top? If so, how many, and where?

 

[Daniel Stevens]

Ah, so we're talking a big tank here then

In the terms I'm familiar with, that's a 5x2x2' tank which is a standard 150gallon

For lighting it, you've got options, however using dual 150watt halides and just dual 54watt T5's will be some low light. Does the tank have any braces across the width of the top? If so, how many, and where?

The tank has one main brace across the middle approx 10" wide....
I've just replaced the t5's with new (actinics) and also the halides with 150w 20'000k halides, and the difference is amazing.
Big Tank!!!! Yes.. and i only paid $850 australian, complete with chiller, lighting,skimmer, live rock,fish,anenome,leather corals etc etc....
And the big bonus is i get to collect my water fresh from the sea. So no mixing of synthetic waters.
Reading some of the forums from around the world i think i've got it easy.
All i need now is to broaden my experience and not become complacent.
When i find out how i'll post pictures for those interested.

 

[SkiFletch]

cool. Just an FYI, 150watt halides really only cover a 4 square foot area (2'x2'). They'll struggle to cover a 5 square foot area (2.5'x2') that you have. And of course, the T5's will not cover the entire length of the aquarium as they're a foot short.

That being said, try to concentrate your corals underneath the halides and avoid the edges and center of the tank where the light will be lower. Might be a good idea to setup your LR as a pair of outcroppings with swimming room around the edges of the tank and middle to maximize what you've got .

Lastly, upgrading your ballasts/bulbs to 250watt or even 400watt would let you keep corals on the edges if you ever do want to do so in the future