what are my wpg

[travis74]

Have been reading threads on lighting and am confused about the actual WPG on the lights I just ordered. This is the link http://www.thatpetplace.com/Products/KW/current/Class//T1/F38AA+0434+0058/EDP/44123/Itemdy00.aspx. Thanks for feedback. [/b]

 

[rich311k]

That fixture as sold will give you 96 watts of usable PC light and 96 watts of atnic light which doesn't count for your overall lighting. You can rplace the atnic bulb with a 6500k or 10,000k bulb for 192 watts. How many gallons is your tank?

 

[travis74]

Yeah that would have been helpful in the equation. 40g. So the actinic bulb provides no usable light? If I did get the 6500k bulb and brought it up to 192 watts would that be overkill? 4.8 wpg then?

 

[rich311k]

You would have to be on top of your ferts and your co2 would have to be 30ppm and stable. You could always just turn on one bulb untill you are ready for both.

 

[czcz]

Yeah that would have been helpful in the equation. 40g. So the actinic bulb provides no usable light?

Part of its output is in the photosynthetic spectrum, so it's partly usable, but often it is easiest to just ignore the actinic half. Actinic is certainly not as usable as the daylight bulb Rich recommended.

If I did get the 6500k bulb and brought it up to 192 watts would that be overkill? 4.8 wpg then?

Using lumens/watt, it's more like 6.5wpg T12 NO. Definitely very high light.

Here's some calcs for you. 1st is that fixture as is, then if you replaced the actinic with a 50/50 bulb, then if you replaced the actinic bulb with full daylight. Remember, with the modern concepts you've read about, that lumens/sq in is the most important number, though at your tank size wpg is a good approximation. You can compare these numbers to real life tanks on Ozz's site here.

travis74's 40g
          Eq T12 wpg  Lumens   Lumens/sq in
96w CF          3.24	 7622.4	11.76
144w CF         4.85   11433.6	17.64
192w CF         6.47   15244.8	23.53

Rich's advice is dead on: with both daylight bulbs, you're in for a very steep learning curve but with high rewards -- you should be able to grow anything you want but will need command of ferts and high CO2. With the fixture as is, you're around low-medium light and have a very nice, easy learning curve, and can grow many plants.

 

[travis74]

thanks for the calcs. I found the lumens calculator posted and was able to wrap my head around it. Though I interpreted it as being in med-high range. will have to double check that. alot to absorb.

 

[malkore]

one option is to replace the actinic with a 50/50 bulb. then you get an additional 48watts of daylight/plant light, and 48watts of actinic, which might help some plants grow bushier, and might improve the natural coloration of many fish species.

the blue light can really bring out the colors in cichlids.