# Watts per gallon - Reflected or not



## leemonk (31 Jul 2012)

Hey,

After reading a reply in a thread that I am subscribed to it prompted a question (that was unrelated to the thread).

I have just built a Walstad style tank and am worrying a little about the light I have in the tank.

I currently have 2x45w T5 HiLite and a RIO 180 tank. Thus I have around 2.35watts per gallon. Now, this light is NOT reflected.

Lets assume I am happy with 2.35 watts per gallon (though we'll come to that in a minute). Does the watts per gallon measurement normally assume that the light is being reflected to some degree? Either way, if I'm happy with 2.35 w/g and decide to use reflectors, what does that do to my tank? Is it considered to be upping the w/g or does it have another effect on it?

Walstad states that she uses between 2 and 3 w/g on her tanks, therefore I would assume that I am within this 'safe' zone. However I was planning on blocking out one of the bulbs with some standard plumbing pipes to give myself a single bulb of 45w.

Do you think this is neccessary now and also, what effects, if any, will this have on my my tank as the two bulbs are off centre, thus by turning one off, I now have an off centre lighting effect.

Regards


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## leemonk (31 Jul 2012)

Also... how should T5 'HiLites' be measured?

Are these considered to be stronger than their equivalent wattage counterparts?

I am about to order some bulbs from Lampspecs and really need an idea of what i should be looking at.

Given the size of my setup, I think I need the 849mm length and in this length they offer a 21 or a 39 watt bulb. Though I have no idea if these are also considered 'HiLite' or not.

Here is a link to one I'm looking at:

http://www.lampspecs.co.uk/Light-Bulbs- ... 65-Philips


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## Danny (31 Jul 2012)

Not a clue about measuring light other than wpg but I know par is the best way and wpg is almost redundant, but thought this may help with cheaper bulbs  http://www.lampshoponline.com/

Also do you mean HO not HI? or are they the same thing?


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## awtong (31 Jul 2012)

HI lite is just the name given to Juwel branded HO T5's, so HI and HO mean the same thing in this case.

Andy


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## ceg4048 (31 Jul 2012)

Lee,
     As stated above, wpg values are meaningless and it's best not to get too invested in such numbers because X wpg in a given tank is rarely ever the same as X-wpg in another tank. Only PAR is an an objective and consistent value that can be depended upon regardless of light type and source. We use the wpg numbers as rough guidelines only.

Cheers,


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## leemonk (31 Jul 2012)

....... and I'm guessing there is no easy way to measure PAR?

Given that wpg is used as a rough guideline, how should I measure the amount of light I need to order and whether or not that light should have/needs a reflector?

Also.... is HI/HO more powerful than a standard T5? and if so, how do I calculate that against purchasing T5's from lampspecs?

Regards


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## Danny (31 Jul 2012)

T5 HO are roughly double the equivalent wattage output to normal T5 NO  bulbs from what I have read, so you will in effect have 2 bulbs power in one with a HO.

I have x4 54w T5HO on my tank but that is because it is 2.5ft deep lol Think you would be fine with normal T5NO bulbs I recken but I am only just starting to learn about lighting so someone else may give a better answer


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## leemonk (31 Jul 2012)

Thanks.....

Is the HI/HO all about the bulb or about the fitting too? I only ask as I am wondering if I can replace the current HO bulbs with bulbs that are not HO? ie.... will the unit allow for it?


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## Danny (31 Jul 2012)

I do not know for certain but I do not see why not if you can get a NO in the same size and wattage as some HO bulb watts are specific sizes to HO.

The actual end pin fittings are the same as far as I am aware.


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## ceg4048 (31 Jul 2012)

leemonk said:
			
		

> ....... and I'm guessing there is no easy way to measure PAR?


Hi Lee,
   It's very easy to measure PAR. All you need is a PAR meter like this Apogee Quantum Meter. They are expensive though, so it's better to beg, borrow or steal one.







			
				leemonk said:
			
		

> Given that wpg is used as a rough guideline, how should I measure the amount of light I need to order and whether or not that light should have/needs a reflector?


I think you should avoid getting wrapped around the axle with light. If you are worried about it then why not use T8 lights instead of T5? Plants do not "need" lots of light or even special quantities of light. It seems that it's people that need all that light.

Cheers,


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## leemonk (31 Jul 2012)

Thanks for the replies guys.

I think I might have a larger problem. I have removed one of the bulbs and it appears to be 900mm pin to pin. The T5's on Lampspecs site measure 849mm. 

Any ideas on what I bulbs I can use? Am I able to use T8's or will I have the wrong unit for that? I really really can not afford to replace the lighting unit.

Just to clarify that I am right with teh current setup. My bulbs measure 15mm in diameter

Any ideas?

Regards


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## Danny (31 Jul 2012)

That is a T8 then not T5 I think, 25mm bulb where a T5 is 15mm.


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## Danny (31 Jul 2012)

not 45w but the right size https://www.bltdirect.com/product.php?pid=7746


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## leemonk (31 Jul 2012)

Really appreciate the assist Danny, but I think you might have misread my post. The bulbs I have are 15mm.... so guess that makes them T5's.

Can I plug T8's into a T5 unit?

I think I read somewhere that the Juwel light units are a little odd...... not sure if anyone can confirm


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## Danny (31 Jul 2012)

I do not have a clue about putting a T8 in a T5 unit sorry lol but from a quick look at the Jewel bulbs they are 895mm in 45w and fooking expensive lol

I used these, just wired them up with some twin and earth added a plug and job done  not sure if they have them in 3ft though...
http://www.ebay.co.uk/itm/JCC-2-X-54W-T ... 1298wt_908

You could get one of them and bulbs, wiring etc for less than a single Jewel bulb lol


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## ceg4048 (31 Jul 2012)

leemonk said:
			
		

> I think I might have a larger problem. I have removed one of the bulbs and it appears to be 900mm pin to pin. The T5's on Lampspecs site measure 849mm.


Lee, you cannot use independent bulbs for a Juwel tank because Juwel wants to lock you into overpaying for their bulbs. That's why the dimensions differ. In order to be able to use independent bulbs you would have to change the entire unit to an independent unit. Since you have stated that you cannot afford to change the lighting unit then this option is not available. You therefore must use Juwel bulbs or whatever bulbs are manufactured to Juwel specifications, which are likely to be similarly priced.



			
				leemonk said:
			
		

> Any ideas on what I bulbs I can use? Am I able to use T8's or will I have the wrong unit for that?


I doubt that you can use T8 tubes because generally the socket specifications are different. The bulbs are different diameters and so the spacing between the pins are different. Being a wider diameter bulb, the pins on the T8 will have a wider spacing between them.

There are lots of ways to reduce the lighting entering the tank. You could easily use floating plants to block the light. A lot of low tech-ers like to use frogbit, but any of the floating Azollas, Eichhornias, Pistia, or Salvinias will work to block the light. You could also use a darkend glass or acrylic, or even cheesecloth to block some of the light. Just use your imagination and whatever resources available to you.

Cheers,


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## awtong (1 Aug 2012)

iQuatics do Juwel specification tubes.  I am unsure if they are cheaper or not but might be worth giving them a look.  I haven't bought tubes from them only the reflectors for my Juwel lights.  Service I received was top notch.

Andy


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