Lighting Choice

[Westy]

Hi,

I have high phosphate levels so am going to give the scrubber ago.

I have a 4ft x2ft x2ft Marine tank with a sump underneath.
Have made a 12" x 24" scrubber and this will lie at an angle in the sump. There is only room to light it from one side.
I have been trying to find CFL 23W bulbs with a 2700-3000k colour temp as per your recommendation.

I have found these:
http://www.lightbulbs-direct.com/produc ... hr-23w-es/

Would they serve the purpose, may need to get two of these as the the scrubber is quite large.

Thanks
Westy

[SantaMonica]

You have 16 cubic feet, which is 120 gallons. High filtering would be 120 total watts; medium filtering would be 60 total watts. The bulb you found would work; you would need at least 3 of them, with reflectors.

For 120 gallons, you need:

120 square inches (750 square cm, such as 27 X 27 cm) if two sided vertical.
240 square inches (1500 square cm) if one-sided vertical.
480 square inches (3000 square cm) if non-vertical.

Yours is non-vertical. These are the least efficient because growth stops the water from flowing, so you need a much larger area. You said 12 X 24 inches, which is 288 square inches. Not enough for a non-vertical, if you use the above guideline. You can try it if you want, but it won't handle regular feeding (although light half-feedings may be ok, if you have 120 watts).

A more accurate guideline is the new one for feeding:

Each cube of frozen food you feed per day needs:

12 square inches of screen, with a light on both sides (two sided vertical) totaling 12 watts.
24 square inches of screen, with a light on one side (one sided vertical) totaling 12 watts.
48 square inches of screen, if non-vertical, with a total of 12 watts.

If we guess that you will be feeding 10 cubes a day, you would need 480 square inches (non-vertical), and 120 watts, which turns out to be the same as the guideline for gallons. If you cut the feeding to 5 cubes, your planned size of 288 square inches will work, if you have 120 watts. If you also cut your watts down to 60, you'd have to cut your feeding to 2.5 cubes.

It's really the feeding that controls how strong your scrubber needs to be.

[Westy]

As my phosphate levels are fairly high I have not bought any livestock for a while.
I only have 3 fish, snails, crabs and starfish.

Feeding is almost negligible, possibly the equivalent to 1 cube every other day...although its actually a pinch of New Era Aegis Marine flakes.

Looks like im ok to go with x3 23W bulbs with the small quantities of feed i giving.

Thanks

[Westy]

Im having a redesign as I can make the scrubber smaller so its 120 square inches and will be able to light it from both sides using multiple bulbs.