Juwel Rio 300

I have just bought a Juwel Rio 300 which comes with 2 x 38W lights which are 120cm long. I have also fitted reflectors in an attempt to ensure that all the available light gets to the tank.

My question is: Will this set up provide me with enough light to go for a decent planted tank? When I say decent I am aiming for a variety of plants which will form a nice background for my tank and compliment the fish. I want a bit more than just a token effort at planting.

All advice and views gratefully received.

A 300 litre tank with 76W gives you about 1 Watt per Gallon. You'll be fine growing some low-light loving plants i.e. Anubias sp., Java fern, Java moss etc. You won't need CO2 and very little fertilisers. However if you want a densely planted tank you will probably have to double your light at least. CO2 would help too. Really depends on what your budget is and what plants you want.

Hope this helps and good luck. Keep us posted.

gf225 thanks for the reply

Juwel's website says that using the reflectors 'doubles the light'. Now I am pretty sure it doesn't increase the light levels that much but it does help. Anybody have any knowledge on the impact reflectors have.

Also when considering watts per gallon, do you need to account for daylight the tank receives?

Is it possible to get standard t8 tubes which are say 60W or are they all generally 10W per foot? I know that in marines you can get t5 and metal halides but they are fairly expensive, come in shorter lengths and cause problems in keeping the temperature down.

Hi mate,

Reflectors do help a lot IMO. I use them and consider them a must if growing plants, all the light is directed downward thus increasing efficiency considerably.

You should try to avoid too much daylight as this will encourage algae, I wouldn't use it when calculating WPG, the same goes for reflectors.

T8 tubes are all like you say approx 10W per foot. If you get some good quality tubes (full-spectrum) and use reflectors you may have some success with 1 WPG. My Juwel Rio 125 had only 1 WPG and I managed to grow a good variety of easy plants. I'm upto 2 WPG soon to be 3 WPG but have co2 and a failrly high-tech setup (and expensive!!)

Here's the difference!!

Do you work for a lighting company, because those are pretty good before and after shots!!! I think I shall try my luck and see how things grow and take it from there.

Many thanks for your advice and once again, nice tank.

gf225 said:

If you get some good quality tubes (full-spectrum) and use reflectors you may have some success with 1 WPG.

Click to expand...

Hello.
Full-spectrum tubes (example: Osram 9xx) have approx. 20% less light efficiency than tubes with 3 peaks (Osram 8xx. Sorry, dunno the english word).

However, they have a better colour rendition.

For my 240l tank, I'm using 2x38W with reflectors. The plants grow like weed.

I'm planning to get 420l. I already have 2x54W T5 tubes for it- additionally to the 2x38W T8.

Hello.
Full-spectrum tubes (example: Osram 9xx) have approx. 20% less light efficiency than tubes with 3 peaks (Osram 8xx. Sorry, dunno the english word).

Click to expand...

AFIK, there are no true full spectrum fluorescent bulbs; all fluorescent bulbs produce white light by mixing the three (red, green, blue) lights togather. Full spectrum adds one or two additional phosphors to produce lights in UV or other wave length to fill some gaps. Only the sun with many different gases is capable of producing full spectrum with no missing wave lenghts.

I'm not sure how the efficiency is measured, but if it's measured in lumens per watt, then it's some what misleading. Lumen measures the intensity as seen by the human eye. Since human eye is biased toward the green spectrum of the light, if the light produces primarily in red and blue spectrum (as in plant "gro-light"), then it will make the light appear dim.

@blue ram:
yes, there aren't true full spectrum lamps which have the same light like the sun.
However, they have more luminescent substances which cover the gaps, so they get closer to it. The 9xx also aren't called full-spectrum, but De Luxe.
Special tubes for fishtanks are nearly the same, but they are sold as full-spectrum.

Well, on this site there are some spectrums:

http/www.hereinspaziert.de/spektren/spektren.htm

It's in german, I don't know an english site explaining this.
The first image on the right side shows the spectrum of the Osram Lumilux 830(Three peak tube).

In the second picture, the white line shows the spectrum of the Dennerle (Trocal) Special Plant. The spectrum of the cheap Osram tube is very similar to it...

The third picture shows the spectrum of an Osram 930 (de luxe)

And yes, the efficiency is measured im Lumen per Watt.
The 8xx tubes provide the best light efficiency for the human eye, the 9xx have the best colour rendition- also for the human eye.
However, the Trocal Plant is a special plant tube with 3 peaks.

A comparison between the light of this tube and the spectrum measured in a greenhouse (broken line) is drawn in this picture:

Smallerboy,

I ditto what George has said.

Juwel reflectors direct the existing light output . but directs it all (or most of it) downwards into the aquarium where you want it.

I agree with George on natural sunlight, it can lead to algae problems.

I have beefed up my Juwel 400 with T5 lighting (in addition to the existing lights) which has a greater output per watt than T8 and the light reaches deeper into the aquarium. I assume your Rio 300 has the same depth as the 400 which is 24" before displacement.

Arcadia now produce T5 balasts which fit inot the Juwel hood, but they are quite expensive. The cheeaper option would be to buy the arcadia starter kits.

Even if you want to just use T8s, it will all help.

When you get over 2wpg Co2 can really help, but if you go higher it becomes a necesity to use and so does fertilizer.

Thanks all.

I shall see how things go and if I decide to grow more plants or more difficult plants I shall probably look at Arcadia's I bar system which uses high output T5's.