lighting questions, 20g and 10g

[James_in_MN]

I recently made the mistake of adding plants to my tank, which had an Aqueon deluxe hood with 15w bulb on my 20g high. Since I knew I had low light, the plants I added were anacharis, crypt, and java fern. After a week, the anacharis was in full melt mode, and the crypt and java fern was in bad shape.

I then decided to stop trying to get by on the cheap and replaced my light with this:
Amazon.com: 24-36 in. Marineland Double Bright LED Light - 8 x 1W white - 4 x .06W blue: Kitchen & Dining

Although I lost the anacharis plants, my crypt and java fern made a quick recovery. The thing is, it's an LED light, and since the wattage is different than other tank lights, I'm not certain what types of plants I may now add to the tank. Or, for that matter, have I run the risk of adding a new problem of algae-a-plenty? How does a 600 lumen LED light rate in the wattage-per-gallon rule of thumb?

My other question concerns the lighting on my 10g Aqueon tank. The stock lighting that came with it is a 15w fluorescent fixture. I'm hoping that it should allow me to keep low light plants in the tank (15w/10g = 1.5w/g) like java fern or java moss. Am I correct? I'd prefer not to have the same messy problem I did with the anacharis melt I had to clean up.

 

[fort384]

As for your 10g tank, 15w will probably sustain some lower light plants, assuming the bulb is suited for FW plants. Do you know what color temp it is?

The WPG rule is great for medium sized tanks... but it can't really be applied to small tanks or large tanks.

You have 1.5WPG, yes... but it isn't comparable to having 1.5WPG over a midsized tank, like a 30 or 55 gal. If you go smaller, it becomes even more clear what I am saying: If you have a 5 gal tank, 1 WPG won't grow anything. And for large tanks... say you have a 125 gal tank... having high light on a tank like this does not mean you need 3 or 4 WPG... That would cook the plants, not grow them . I guess my point is, the WPG "rule" is a great guideline for medium sized tanks. But it is only a guideline. There are a lot of factors that determine the quality and category of lighting you have... type of bulb, size of bulb, wattage, color temp, spread, PAR, distance, etc.

As for the LEDs... I will let someone else jump in on that. I haven't used LEDs over a planted tank yet. I know we have a couple of folks that frequent the forum who are using LED fixtures and can give you the first hand experience on it, rather than what I have just read.

 

[James_in_MN]

I knew that WPG was useless with very small and very large tanks, but didn't know that my 10g is one of those that fits outside that guideline.

It's an Aqueon 15w T8 18" bulb. It does say 8,000K full spectrum daylight; my guess is that's the color temp?

What I'm looking for with the LED is just a general idea on how it performs vs other lighting systems for a 20g high tank. Am I looking at so much light that I'll have an algae explosion?

 

[fort384]

Yes that's the color temp and it's good.

Of course it is all a bit of opinion, but I think the WPG rule is good from about 20-65 gal.

 

[James_in_MN]

I was still wondering about my LED light on the 20g high. Does anyone have any experience with the Marineland LED lights?

 

[fort384]

James, I will push your question to some folks who can give you a much more knowledgeable answer on the LEDs... I haven't used LEDs on a planted tank yet, but a lot of folks are doing so successfully.

 

[BigJim]

The fluorescent Wpg rule is useless for LEDs in general. I've got 30W of Cree XR-E diodes on my 20H and I'm pretty sure I can grow whatever I want. I've got three species of high-light plants that are growing nicely in that tank and I've got the LEDs dimmed to about 2/3 brightness or about 1 Wpg.

That Marineland LED fixture should be good for medium-light plants at least. LEDs are pretty new to the aquarium hobby, so there aren't many rules of thumb yet. You'll have to experiment to see if you need CO2 or a fertilizer regimen. I'm not running either yet, but I've got the tank heavily stocked and I'm starting to see holes in the leaves of my plants, a sign of nutrient deficiency.

 

[Crepe]

LEDs do put out a ton more PAR and lumens per watt than regular lights. I can't give you an exact number but let's just say it only takes about half or even a third the amount of LED wattage to equal something like T5s. I rarely see LEDs on FW so this is just what I observe in SW tanks...

IE it takes about 8x 10k 3watt crees + 4 Actnics to for 36watts on a 10-20 gallon for high light reef lighting where as it would be around 48-60 watts with T5HO.

edit: I may be wrong...but I do distinctly recall someone bleaching one of their corals with such a set up on a 10 gallon tank...

 

[azure bones]

I know there is someone on here using the marineland led on a low light planted tank ill try and find it

Sent from my Droid desire using Aquarium

 

[James_in_MN]

That Marineland LED fixture should be good for medium-light plants at least. LEDs are pretty new to the aquarium hobby, so there aren't many rules of thumb yet. You'll have to experiment to see if you need CO2 or a fertilizer regimen. I'm not running either yet, but I've got the tank heavily stocked and I'm starting to see holes in the leaves of my plants, a sign of nutrient deficiency.

Up to medium light plants would certainly work for me. I just replaced all the plastic plants in my 20g high with anacharis and corkscrew val, and hopefully won't have the same problem I had before. I also bought Seachem Excel from my LFS (on his recommendation) and have been adding it to the tank.