PL vs normal fluorescent lamp

[greenwaters]

Halo,

I have a normal 3 ft tank with some normal plants eg. echindoras, difformis, riccia, java moss, tiger lotus and tennullus.. CO2 is DIY. I have 3 X 3ft DIY fluorescent lamp (same as those used on ceilings). I notice the riccia seldom or never Pearls and the tiger lotus are not as red as they should be but they are generally all growing ok. Also i cannot achieve the "bright sunny" look like those "old bird's" tanks shown in AQ.

I want to add another one more 3ft lamp so that i will have 1W per gallon... or should i get rid of all the fluorescent and change to PL instead? Is there any major difference?

[bclee]

Basically, PL and FL gives about the same lighting level per watt. The advantage of PL is the compactness. Therefore, you can squeeze more wattage of PL in the same space than with FL.

Go for 2~3W (PL or FL) per gallon. If you have space constraints, convert to PL. Otherwise, you can stick to your current FL and add more lights... or upgrade your current FL, maybe you may not need a new set of lights.

BC

[Allen_1971]

The major advantage of PL light is that it is more compact than Fluorescent tubes... allowing you to pack more light into a smaller area... For a 3ft tank, it usually isn't a problem to pack 4x36W PL tubes in or 2x55W... You really should look to get about 3W/G.

[budak]

What's the total wattage of your 3 existing lights? They must be pretty low if you need another to get 1WPG. There's threads on PL vs FL lights in the equipment section, but the basic differences are: you can pack more PL units for any one tank compared to FLs, and PLs generated more heat, so a fan is highly advised.

Actually, 3 x 3 ft FLs (assuming each is 30W) should be enough for your plants. You should change the tubes if they are more than 8 months old. Also check the colour temperature (the K number should be indicated at one end of the tube), 6500K-8000K is ideal - too high promotes algae, while too low it looks too tinted.

Some folks use the expensive planted tank FL tubes, but others report good results with cheap Hitachi EBT or Philips tubes available in hardware stores.

[vinz]

Recalculate your tank volume and lighting.

Assuming 3'x1.5'x1.5', your water volume should be about 40Gals. 2ft FL tubes are about 18W and 3ft FL tubes are about 30W. Three of these will give you about 1.35 to 2.25 W/Gal.

[juggler]

3ft tanks are ideal candidates for PL lights because:
1) 36W PL lights are about 16.5" in length. Two of them would fit nicely under 36".
2) 3ft 30W FL tubes are not easy to come by as is the 30W ballast. The more common lengths are 2ft (18W) and 4ft (36W).

So, if your tank size is 3x1.5x1.5 (51 gal), then 4x36W PL tubes would give you about 2.8W/gal.

Shall we move this discussion to the Equipment section?

[Simon]

i do prefer FL since the light is evenly spread and no dark corners like the PL, problem is like what some of the rest have mentioned, PL pack more wattage.. one thing about FL, the penetration depth is less than 2ft.

KF, i thought 30watts FL is widely available?

[vinz]

In case anyone wonders why I got 40gals and juggler got 51 gals...

I calculated water volume, subtracting some height for base fert, etc (assumed). KF calculated the full tank capacity.

[vinz]

Moving to equipment forum...

[juggler]

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On 2/5/2003 11:36:20 AM

i do prefer FL since the light is evenly spread and no dark corners like the PL, problem is like what some of the rest have mentioned, PL pack more wattage.. one thing about FL, the penetration depth is less than 2ft.

KF, i thought 30watts FL is widely available?
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Simon: Right. Sorry. I was thinking of 2.5ft lights and 25W ballasts.

[piggy]

Just wondering, my tank is 4 x 1.5 x 1.5 ft, with 4 x 36w fl lightning, is the lightnings sufficient for my tank?

Thanks and regards.

[vinz]

Piggy,

Assuming 4 inches lost to substrate, etc... 4x36W is just barely enough. If you put the light demanding plants in the brightest areas, it's good enough.

[juggler]

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On 2/5/2003 3:24:13 PM

Piggy,

Assuming 4 inches lost to substrate, etc... 4x36W is just barely enough. If you put the light demanding plants in the brightest areas, it's good enough.
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I used to have a 4x1.5x1.5 setup with 4x36W FL. Only non light-hungry plants do well. Only much later that I converted to 6x36W PL. There were improvements but very soon after I upgraded that tank to a 5ft. See my site for more info and plant list.

[piggy]

Vinz, Juggler,

Thanks for the reply, one more question, as for my currently 4x36w lightnings, I need to clean the aquarium wall very 3 days cos the algae that grown on it is super fast, is it becos of the lightnings or is there any other problem that actually contributed to algae.

Thanks and best regards[:]

[vinz]

Most likely an inbalance of nutrients in the water.

What fertiliser are you using and what is your dosing routine? Do you know your CO2 levels (i.e. pH, KH levels)?

[piggy]

TO be frank, I never test the water, as long there is no algae within the tank, fish dont die and plants grows and keeps on blubbing, change of water every 1 week, its fine for me. Just would like to enquiry, what kind of fertiliser do you recommand, both liquid and solid. What other nutrients do I need for my tank? How much dosage should I give? Need your advice, and I will start redosage my tank with your advice. Thanks very much and sorry for the inconvience caused.

[bclee]

If you do not test the water, you have to base on guess work and trial-and-error.

The fertilisers are all out there: TMG, Seachem, JBL, Sera, Dennerle, etc. All will work. It is very difficult for anyone to advice without knowing the water parameters. All I can say is follow the instructions on the labels.

Thereafter, you can increase or decrease the dosage base on your observation.

Another aspect is the NO3 and PO4 level. Most aquarium fertilisers do not contain these. Normally, you have to test the water and dose accordingly. If no testing, chances are you may make a mess out of it. Probably for the time being, skip it, unless you are finding persistent algae problem or poor plant health.

BC