Seagrass Lighting?

[Privateye]

I started a 29 gallon seagrass tank today. Well, so far it's just the substrate, a couple of sand dollars, and a few hermit crabs. The seagrass will go in next week. It will mostly be Halodule but I might add some Thalassia later.

Does anyone have successful experience with artificial lighting and seagrass? I'm wondering what I should use. I may have a small budget to put towards this, but I also have some old lights in the garage. T5 (2 bulb HO), T5 (2 bulb standard output x 2), one of those old Marineland hidden LEDs, T8 lights (1 or 2 bulb), and a 24" "reef capable" LED light from Lifegard Aquatics (it is not reef capable - I tried). I'll probably use the hidden LED strip with something else.

Power compacts worked really well for pretty much any freshwater plant I tried in the past, but the technology is kind of disappearing due to price and inefficiency.

 

[mcarroll]

I may be wrong but I think those are universally shallow-water habitats...regular "white" grow lights would probably work well. I'd try looking up the amount of light you'd need to reach their compensation point and saturation point....and if there is a "too high" level to avoid above those.

 

[oreo54]

I started a 29 gallon seagrass tank today. Well, so far it's just the substrate, a couple of sand dollars, and a few hermit crabs. The seagrass will go in next week. It will mostly be Halodule but I might add some Thalassia later.

Does anyone have successful experience with artificial lighting and seagrass? I'm wondering what I should use. I may have a small budget to put towards this, but I also have some old lights in the garage. T5 (2 bulb HO), T5 (2 bulb standard output x 2), one of those old Marineland hidden LEDs, T8 lights (1 or 2 bulb), and a 24" "reef capable" LED light from Lifegard Aquatics (it is not reef capable - I tried). I'll probably use the hidden LED strip with something else.

Power compacts worked really well for pretty much any freshwater plant I tried in the past, but the technology is kind of disappearing due to price and inefficiency.

Some info on Thalassia..
https://onlinelibrary.wiley.com/doi/10.1111/j.1744-7909.2010.00991.x

You don't list the sizes of the lights
Marineland hidden came in 2 sizes AFAICT. 17-inches and 21-inches.
Output is probably meager.
Blue and white leds.

I recommend getting a new 30" light for your tank. Is it "necessary" .. well no, just is more aesthetically pleasing.
standard 29gal
30 inches long x 12.5 inches wide x 18.75 inches tall
https://www.saltwateraquarium.com/3...JIZNTpJn43FS0mpSGodKAeZuih1D5riBoCNmMQAvD_BwE

Slightly over $100. Listed par is 80 at 14" 29 watts.
Any t5's will be equiv at like 43 watts total

Your plants seem to be able to take way more par (wattage) like reef levels but it gets to be way more $'s
As to color the likely natural environments are green/blue rich and cool.

Many freshwater RGB lights start out at 10000k-ish
AI Overview

Growing seagrass in a marine aquarium requires a specialized setup because they are true vascular plants with root systems, unlike typical macroalgae. [1, 2, 3]

Key Requirements

• Deep Substrate: Seagrasses absorb most of their nutrients through their roots and need a thick sand or mud bed. Depending on the species, you need a depth of 3 to 6 inches (such as a mix of live sand, aragonite, and organic mud like Miracle Mud).
• Intense Lighting: They have high lighting demands (full-spectrum daylight or 10k LED lighting) to support photosynthesis.
• Water Quality & C0₂: Maintain stable saltwater parameters, and some advanced setups use a CO₂ injection system to boost plant growth.
• Avoid Large Herbivores: Keep out large herbivorous fish or aggressive diggers that uproot or eat the blades

 

[mcarroll]

Someone just posted this in another thread:
https://web.archive.org/web/20260618132626/https://www.marineplantbook.com/

(scroll down that link to the seagrass section)

https://web.archive.org/web/20260618132626/https://www.marineplantbook.com/marinebookturtle.htm

 

[Privateye]

Thanks guys!

I'm actually not too worried about anything other than the light. I've grown plenty of seagrass before, just not much with artificial lighting.

I did turtle grass long ago, but this time the main focus is on shoal grass. Too bad because I like the look of turtle grass more. I set this tank up to help me learn as much as I can about growing seagrass. While shoal grass is reported to be easier (because it's a pioneer species) I feel I've seen the opposite at times. People tell me "It grows well in shallow environments. It often gets exposed at low tide." But I can confirm many times over that if a part of that blade dries out (happens in less than 30 minutes) it will not survive. Maybe shoal grass can tolerate losing blades better though.

Anyway, I found out that the T5HO fixture didn't work. I tried new lamps too (got them for $1!). I'll know whether it can be fixed by next week.

For now I have the Lifegard LED and the Marineland hidden LED (21") on the tank. Both are mostly white with a little blue. That's where I stand at day 1.

I actually really liked the hidden LEDs. They aren't strong enough to be the only light source, but the blue strips work great for accent and boosting color. They're way more than a moonlight. As I recall, the LEDs are 0.6W each. I want to say it was about 50W total for a 21" light based on an old memory. I use them as a supplement.

I'll be borrowing a PAR meter soon. Their ideal requirements are a little below SPS from what I recall.

 

[oreo54]

Thanks guys!


I actually really liked the hidden LEDs. They aren't strong enough to be the only light source, but the blue strips work great for accent and boosting color. They're way more than a moonlight. As I recall, the LEDs are 0.6W each. I want to say it was about 50W total for a 21" light based on an old memory. I use them as a supplement.

I'll be borrowing a PAR meter soon. Their ideal requirements are a little below SPS from what I recall.

AI Overview

The 21-inch Marineland Hidden LED Lighting System (Model NV33111) has a power consumption of 5.28 watts.

Key Specifications

• Wattage: 5.28 W
• Light Output: 550 lumens
• LED Types: 6,500K white LEDs and 460nm blue LEDs (approx. 0.06 watts per individual LED)
• Modes: Inline 3-way switch (Off, Blue only, or Blue + White LEDs)
• Design: Fully submersible with an in-frame clip or suction-cup mount and directional adjustment dial.

That one?
Believe I said meager output. Didn't know how meager.
But all depends on distances.

Addendum, That was so low I had to at least attempt to check it.
Found this:
https://www.petsmart.com/fish/heati...led-lighting-system-for-fish-tanks-16486.html