Yet another lighting question...

[Darb21]

My tank has been up and running since about March 1 and I feel as if I've had pretty good success with it. Its a community tank with a few plants.

Haven't lost one fish very stable water parameters... its been really easy to care for and very enjoyable to have. My question is this. Other than that red crypt in the back, the other plants seem to grow at less than a snails pace. They are all healthy and green, just not growing hardly at all. I'd like to get them going a bit. Here is the light I currently use.

http://www.hellolights.com/30aqt5dolist.html

I realize that is really low light for a 29 gallon tank, but it looks to me like its doing enough to keep everything nice and healthy looking and green. And yes, the fixture still has the acintic bulb in it.

My question is this: If I replace the acintic bulb with another daylight bulb, will that make a noticable difference in the plant life? And the bonus question is wether to get a 6,700K bulb, or another 10,000K bulb.

Thanks in advance!
Brad

 

[JustOneMore20]

The plant on the right, on the driftwood looks to be an anubias and they are very slow growers. I have one in my 55g with 2.4wpg and it still grows slow, so IMO more light won't really speed it up any. I can't tell what the other plants are. The one to the left of the crypt looks like a sword. I don't think they are terribly fast growers either.

If you replace the acitinic bulb, you will still be in the low light category. Most people say that an acitinic bulbs gives you only half the useable light, so that would mean you have just under 1 watt per gallon now. Replacing the bulb will only give you just over 1wpg, so not much difference.

The red crypt looks great by the way. Really big.

If you are interesting in getting a higher watt fixture, I have this one over my 29g. It gives me just over 2wpg and I can grow medium and some high light plants very nicely.

 

[rich311k]

I would change the bulb. you will get a bit faster growth. It still will be a low maintenance tank and you can experiment with a few new kinds of plants if you wish. An atnic bulb adds no wattage to your available light totals.

 

[Darb21]

The red crypt looks great by the way. Really big.

Thanks! Go figure... thats the one thats under the actinic bulb in the back! But yeah, that one has grown quite a bit. My Cories and my Kuhlis love that plant for cover!

I think I will go ahead and replace the actnic and see what happens. I just looked up a 6700K replacement bulb for this fixture at Hello Lights and its only 7 bucks. May as well and see what happens. If I don't like it, I can always but the actinic back in there. That'll put me at 1.24 wpg, so we'll see how it does. Thanks for your comments!

 

[Apocalypse_Gold]

Some on this site argue that t-5's are straight power compacts, so your effective wpg would be slightly higher under the "revised wpg rule" but still under 2. More light for your plants but still low maintenance.

 

[Tong]

I'm going to argue in the opposite direction and argue that you might have less light than you think. Smaller light bulbs produce fewer lumens per watt than larger ones. For example a good 4' daylight T8 32 watt bulb produces 2800 lumens (87.5 lumens per watt). However the same bulb in 18" 15 watt form only produces 620 lumens (41 lumens per watt). Now I know my example uses normal fluorescent bulbs but if you check the lumen output on CF bulbs you'll notice this is also true. This, I believe, is another reason why the WPG rule doesn't work for small tanks.