How much lighting do I need?

[seem]

Hello, I'm in England. Could you please explain to me what I need to get my lighting right.

I have a 48x18x12 inch 200 litre aquarium with just 6 plants. I don't know how much PAR I need for 18 inch depth minus the 2 inch substrate and for growing plants. I don't understand PAR.

I have purchased and awaiting the Fluval aquasky as that was a mainstream model alot of aquatic websites sell. 33Watt, 48inch. The Finnex brand is not sold here. The spec is 2240 lumens that works out 13 lumens per litre. I can't find how much PAR it is. I don't want the display bright but don't want it dull and also improve the fish colour display.

Is the Aquasky adequate for me?
Do I need to buy a additional light?

 

[Celestialpearl]

In short PAR is the measurement for photosynthetic available radiation. In other words it is the amount of light available that allows plant to grow. Another way of putting it...PAR is not quantity of light, but rather quality.

You can have a super bright light that puts out a lot of lumens, but if the light is not in the proper wavelength, then it is not of any use to the plant. Plants use light between 400-700nm. -> They use blue, green, yellow and red light.

The trick with PAR is knowing at what depth the measurement is taken. Not every manufacturer provides the information for their unit which makes picking a light an absolute pain. PAR will significantly decrease the further it has to travel in water because light is being reflected and absorbed by molecules. 18in is deep and will require a strong light with a lot of PAR for carpeting plants, and red plants.

High light plants require around 90+ PAR at the described depth to have decent growth. If a light only puts out 70 PAR at 12inches and you want the high light, carpeting, red plants, it is not the light for you. If it puts out 155 PAR at 12 inches, then the light is the one for you because it probably puts out about 90PAR at 18inches of water.

What plants do you intend to keep?

The aquasky is not going to be strong enough for a lush carpet of baby tears. It may grow anubias and java fern just fine.

 

[seem]

Thanks for your post. I'm a little clearer. So will 2 lower PAR lights add up to a bigger adequate PAR overall or will I have to get 1 light with an adequate PAR?

I don't mind if I get a bit of algae as I have Bristlenose catfish that need feeding.

I have added a additional HOB filter which has made the penetrating surface clearer due to the surface skimmer so that will help a little.

 

[Celestialpearl]

So I'm going to try to paste a link to a chart I was looking at earlier when looking over some of the popular options over here in the states. A 48" light strip isn't going to be cheap no matter the option, but if you want a wider plant variety then you are going to need stronger lighting. Hopefully you'll be able to use it. If it comes up funky, let me know and I'll input the info into a chart. Here is the link.

I am trying to find some information on the aquasky PAR values. I don't think it is a high output fixture, but am having trouble backing my claim here. I'd honestly suspect it to be putting out about 50 PAR at 12 inches.

The old standard of watts per liter/gallon or lumens per liter/gallon doesn't really apply as much with LED lights due to the type of light they are able to emit. These lights are able to emit particular wave lengths at various strengths much more efficiently than T8 and T12 fixtures, so PAR measurements are more reliable indicator of use. Watts/lumens doesn't really convert when using LED.

**Edit** I am not able to find any information about the PAR value of the aquasky. Brands I'd recommend are fluval 3.0 and Current USA satellite pro or satellite plus if they are available to you. If you want a more robust light that can definitely do high light look at Kessil and Ecotech Marine Radeon FW and AI prime FW

 

[seem]

Thank you for the examples at 12 inch that finally gives me some idea. I will cancel the Aquasky.

My waters clear. I Iike to grow carpet plants at a later date and would like to light these up well but not bright. I think I need medium lighting.

 

[Celestialpearl]

So will 2 lower PAR lights add up to a bigger adequate PAR overall or will I have to get 1 light with an adequate PAR?

Sort of...it would more less average out. Adding a second light is done to get a more homogenous spread of light to eliminate dark areas for plants. Yes adding another light fixture would increase PAR, but only a little bit as the extra light just helps the darker areas the light from the first fixture was not able to reach. It would not double the PAR value.

 

[seem]

Yes, its like if you put 2 lightbulbs in a room you spread the light but not make it brighter

I've bought a hygger LED light as the Nicrew are poor quality. What do you think the PAR is on that? This one https://www.amazon.co.uk/dp/B0872YF...c_fabc_FH7ZY59MEQDQ5EHEE4FJ?tag=fishloreuk-21 Looks like I need to send this back.

Surprised Fluval Aquasky is not adequate as it has some good features from reading the forum and its 33W and 48". I initially thought the Planted 3.0 was overkill for my depth but not (opinion) but I see its stupidly overpriced.

EDIT: Recommended light, Good lights but outside my budget.

When measuring PAR, is it taken from the light or from the water surface?

 

[Celestialpearl]

When measuring PAR, is it taken from the light or from the water surface?

Good PAR measurements are taken at multiple depths. The first being at the surface of the water (about 3inches below most lights, then in the middle of the water column or at the substrate. So usually at 12in. and 16-18in. for most tanks.

I am not familiar with Hygger lights. I do have a heater by them that I like. Looking at it, hard to say. My initial impression is that the Aquasky may have stronger LEDs. That is the thing about LED lights. It can look super bright to us, but be very dim to the plant because the light is not quite in the right spectrum. It is hard to guess the PAR value unless you have a meter which are expensive. Hence why little data has been reported by hobbyist. Manufacturers aren't helping much either... I did do a search in the reviews and one person guesses that it is around 30, that is totally anecdotal, just like me suspecting the Aquasky is stronger.

I figured I'd throw out the bigger priced lights because the lights for your tank aren't necessarily going to be cheap. You have a long tank, so even the cheap brands are a little costly. I didn't know if the price difference would be too much of an offset to you. And yeah, the Fluval 3.0 is stupid expensive. I got one because I wanted to try it....it will probably be the only one I buy. If I'm going to fork out that much money again I will go big with a Kessel or something.

 

[seem]

I received a Fluval Aquasky 27W wrong wattage. The 33W is 68 PAR at 12 inch. Sent it back. Sent a Nicrew LED planted plus which I sent back. It wasn't penetrative bright enough. The Nicrew not sealed for condensation same with the Hygger.

I couldn't get the Finnex planted here so that left the Fluval Planted 3.0 59W 48" with 120 PAR. I considered that for the brightness it was roughly the equivalent of 2 X 32W lights so the higher price was justified for the brightness of 2 lights.

The Planted 3.0 is a great light and fully waterproof. Puts the Nicrew's to shame and comes with a 5 year guarantee. My criticism, I would like a few more red LEDs.

The Planted 3.0 is 6500K fixed and the Aquasky is 3500K to 10000K. Running a Aquasky 2.0 and planted 3.0 would improve my setup I think.