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Arcadia 18" luminaire - maximum size tank?

ulster exile

6 Jul 2007
Birmingham, UK
Evening all!

The light on my Elite 35 tank has just failed. Hopefully it is just the tube (although I suspect the ballast which is in a sealed unit), but OH has suggested that I take the opportunity and upgrade to an overhead luminaire - I'm doing a little dance as I type this :D

The tank is 50cm long and the 18" Arcadia luminaire is 45cm in new money so will it extend to 50cm? We've been looking at the arcadia site but it doesn't say if the dimensions they are sold under are the maximum distance it will spread over or whether that's the minimum spread.

Additionally, the one I'm looking at includes 2x14W T8's so I'd have just over 3WPG. I know that's over the 2WPG "rule" but we're talking a very small tank, so will I still need CO2 since it's so small? I really don't want to do CO2 on this tank so if I must have CO2 would I get away with dosing Excel?
Cheers Aaron.

OH had already said "no overhang - that would just look stupid!" :rolleyes: It's the ones at Charterhouse I'm looking at atm.
They only seem to sell at 18" T8 light. T5's start at 24"

They sell the 18" light on charterhouse, just click on the link in the previous post and sleect T8 from the left hand menu.

I'm not sure the 18"/45cm will fit securely onto the tank. Bets bet is to phone Arcadia on 0845 8855100

Cheers aaron, £70 isn't too bad really, the real question should really be is 24w going to be enough for the highlight plants we all love.
Mine's a 10 gallon tank...
So 2.4 watts. I wonder what lumens it would give, that seem's to be the best way of working stuff like that out.
Thanks guys :) I emailed Arcadia yesterday and will let you know what their response is. Charterhouse made the mistake of emailing me to find out why I didn't complete my order (I'd a pile of Eheim spares in my basket when I came across the luminaire) and they have replied to say that the legs "should compensate for the difference, this should fit well!".

I'll await Arcadia's response first, but do you guys think that I'd need CO2 with circa 3WPG over a 35litre (9.25 USG)? I have played around with the lumens calculations based upon an average T8 light per the guidelines on this article.

The tank's footprint is 50cm x 25cm, so
50cm = 19.69inches
25cm = 9.84 inches

19.69 * 9.84 = 193.75sq inch

82.8 (lumens per T8 Watt) * 28W = 2318.4 total Lumens

2318.4/193.75 = 11.97 lumens per square inch

According to the article, that's just over "moderate lighting" so in theory, I wouldn't have to worry overly about the light. Any opinions?
I've been impulsive and ordered. I'll be holding onto my Charterhouse email in the event that I need to return it (and they try and deduct the original carriage charge from the refund, as their site implies they will on cancelled orders :twisted: ).
Grrr! Have just spoken to Charterhouse and they've said that Arcadia *may* have stopped making the 18" T8 version, but they're waiting for a call back from the supplier. I'll be so gutted if they don't have this in stock for me, as it seems the only viable shop-bought luminaire small enough for my tank :(

Best bet is to phone them yourself, I did about my luminaire and found them very helpful, they even told me the shops that had bought the particlaur model I was interested in so I could go and have a look at it :)

If Charterhouse can't get hold it for you Arcadia may be able to tell you the local shops that had bought the T8 unit !

Lisa, thanks so much for those links :D First one looked cool, if a bit dear :wideyed: but I think I may go with the second one if the Arcadia doesn't work out. I didn't realise that it was available. Although I like the look of the price of the third, I think that you're right - it would be too small :(

swackett - I still haven't had a response to my emails from Arcadia and I couldn't see a number on their site. However, Charterhouse contacted me today to advise that my unit should be with me tomorrow :) Whether it fits or not is another matter, but it was interesting to note that they don't stock items like this - they take your money and order it from the manufacturer for direct delivery to you or me ;)
Chrisi, the third link Lisa sent would fit on your tank, just depends how much light you want over it ;) up to 47cm tanks or 18.5 inches!
You would have to probably change the tubes too, but that shouldn't be too expensive.
Make sure to give us a review of the luminaire I might consider one myself.
Will do. It would have been nice for Arcadia to have drawn a similar diagram to that Chinese one Lisa kindly posted!
Does anyone know how much 'play' there is in the fitting of these Arcadia units generally? I am considering getting one for a 30 inch tank. Should I go for a 60 cm or a 80 cm model?