Lighting clarification

[thesaiyans]

Hello my husband and I our having a discussion about lighting for our freshwater and saltwater tanks and have been told many things by many people. We need some clarification.
Here are our concerns/questions:
we have a 90 gallon saltwater tank with sump, protein skimmer, many types of corals, ribbon eels, fish, starfish etc.
1 25 gallon saltwater tank with many corals and fish.
and a 40 gallon filled halfway for our fish and alligator snapping turtle that has live plants in it.

1. Does the wattage matter for the lighting? if so how much wattage is necessary per gallon. (I've read googles recommendation from live aquaria)

2. Our 90 Gallon has a 50W metal halide light (used to have 2, need to get another one) along with2 fluval sea nanos for the white light. This has been great for the coral growth but is this not efficient enough?

3. Does LED vs Metal Halide make a difference? (I believe our metal halide is a type of led, i can include the link for the product if necessary)

4. What is the difference when it comes to reef/freshwater for the effects of LED/Metal Halide

5. Is it just the lumens and spectrum of light that really matters?


Thank you for any input into this forum.

 

[Bpb]

1. Does the wattage matter for the lighting? if so how much wattage is necessary per gallon. (I've read googles recommendation from live aquaria)

There are lots of arguments on whether watts/gallon is still a realistic measuring stick. There are so many factors that will change the light delivery of identical wattages supplied by different technologies. With metal halide, you are dealing with different ballasts, reflector geometries, and bulb spectrum/age/quality. Two-250 watt bulbs with different reflectors, kelvin rating, ballasts, and branding can have wildly different output levels. One can be as much as double or more than the other. With leds, a similar case can be made for diode spacing and how tight of optics are used

2. Our 90 Gallon has a 50W metal halide light (used to have 2, need to get another one) along with2 fluval sea nanos for the white light. This has been great for the coral growth but is this not efficient enough?

I would expect a single 50 watt halide to be on the deep low end for light output on a tank that size. Especially if it’s older. I’d strongly consider upgrading...but that would be costly. And if it’s working, sometimes best to leave well enough alone. Efficiency will be different but how important that is will be to personal taste. You could potentially do more harm than good with light shock if you aren’t careful with acclimating you a new light source. Corals hate rapid change

3. Does LED vs Metal Halide make a difference? (I believe our metal halide is a type of led, i can include the link for the product if necessary)

Some will say it makes all the difference on either side of the fence, some will say it makes no difference. You absolutely will not find a consensus here. But metal halide and led are completely different technologies. They can’t be the same. That’s like saying “my square is a triangle”. Both shapes, but fundamentally different

4. What is the difference when it comes to reef/freshwater for the effects of LED vs halide

Conventionally reef lighting will be more blue weighted. Freshwater lighting doesn’t require as high of energy. Plants can thrive in lower light levels.

5. Is it just the lumens and spectrum of light that really matters?

No! Mechanism of delivery is every bit as important. Being able to flood the tank with light from all angles is too often overlooked. That is why large reflectors for halides, t5 tubes, and larger/multiple led panels always perform better than small individual light sources

Thank you for any input into this forum.
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