What bulb combo is best for planted tank?

[strohl71]

I have a 36 inch T5 HO setup over my freshwater planted tank. It allows two bulbs at 39W each. I currently have Hagen brand bulbs: one Life Glo (6700k) and one Power Glo (18000k).

My plants are healthy and doing fine but am wondering if a different combination of bulb types would allow the plants to really thrive.

What combination of bulbs do others out there use?

 

[Joe Gatchell]

What size tank? Do you dose with any fertilizers?

 

[indyplanted]

I use 10k's with good results, its a little more blue which I think looks better than a yellow. Also, different manufactures bulbs burn at different colors so one places 10 are different than another places 10! The 18k is good for the looks of the fish too but not very good(or at all) for growing plants. How big of tank are these over? -Bradley

 

[dw1305]

Hi all,
Even if it is a deep tank that sounds like plenty of light. It really depends upon the look you like.

Have a look at these combinations from the excellent "James' Planted Tank":
<http://www.jsctech.co.uk/theplantedtank/lighting.htm>

You don't need specialist aquarium tubes, any 39W 6500K tube will do.

cheers Darrel

 

[strohl71]

What size tank? Do you dose with any fertilizers?

My tank is a 38 gal (36x12x20). Yes, I dose with Flourish Plant Supplement and Flourish Excel Carbon Supplement.

Sword Plants, Anubias, Java Fern, Java Moss, etc.

 

[Joe Gatchell]

My tank is a 38 gal (36x12x20). Yes, I dose with Flourish Plant Supplement and Flourish Excel Carbon Supplement.

Sword Plants, Anubias, Java Fern, Java Moss, etc.

Sounds like plenty of light, and the flourish combo you should be doing well. I have two 29 gallons that are lit with t5 dual 18w bulbs and I dose with flourish as well and my plants grow like crazy. Don't know if there is much more you can do aside going the co2 route, but you'd have to ask someone else for advice on that.

Oh and you have all the same kind of plants as me, Swords, Anubias, Java Fern & Moss.

 

[dw1305]

Hi all,

Sword Plants, Anubias, Java Fern, Java Moss

These are all classic "low light" plants, so I'm pretty sure this isn't a light problem. If you want faster growth you probably need to up the amount of macro-nutrients. I think that "Flourish Plant Supplement" is just a source of micro-nutrients, so you need to dose N (nitrogen) P(phosphorus) and K(potassium). Even though they are usually bracketed together plants actually need a lot more N & K, than they do P. Flourish sell N, P and K supplements if money is no object.

If you feel happy with the chemicals, you could try dosing KNO3 (potassium nitrate), my suspicion would be that you will see a fairly rapid increase in both growth rate and "greeness". Potassium nitrate is K = 39, N = 14 O = 16 so 39+14+(48) = RMM 101 so 14% N, 39% K.

There is a dosing calculator <http://www.jsctech.co.uk/theplantedtank/calculator.htm> on James' Planted Tank and the recipe for his "all in one solution". <http://www.jsctech.co.uk/theplantedtank/allinone.htm>

The Excel is based on glutaraldehyde, it is an organic carbon source but its exact mode of action isn't fully known, so it is difficult to quantify its effect.

I grow very similar plants to you, and as well as being "low light" they can also be grown both without additional CO2 and at very low nutrient levels if you don't mind growth rates being sub-optimal.

Personally I run all my tanks with plant growth nutrient limited.

cheers Darrel

 

[strohl71]

Hello again -

I replaced my 18,000k bulb with a 10,000k bulb a couple of weeks ago. I kept the 6700k bulb in place. The tank lighting is a bit more "yellow" to the eye but still looks good. Maybe my school of cardinal tetras do not look quite as good as before but still look fine overall.

I do want to report a difference that I have noticed however. When I first put in that 18,000k bulb there was an increase in green hair algae.

Now that I have replaced the 18,000k with the 10,000k, the algae growth has been greatly reduced. I think that 18,000k bulb promoted unwanted algae growth.

 

[dw1305]

Hi all,

Now that I have replaced the 18,000k with the 10,000k, the algae growth has been greatly reduced. I think that 18,000k bulb promoted unwanted algae growth.

The differences in algal growth definitely aren't due to the light colour (Kelvin value). The reason I can be so sure is that the Green Algae (Chlorophyta) have exactly the same set of photosynthetic pigments (chlorophyll a & b, and accessory pigments) as all the higher plants from the mosses through to the flowering plants. Their response to light is exactly the same as all the higher plants, although they may show a response more quickly.

You have to remember that the K value and CRI etc are not directly relevant to plant growth, they are entirely to do with the way that we view the light.

Cheers Darrel

 

[codegazer]

Hi,

I have a 30 gallon tank with some plants, 2-3 bunches of different plants and I have just 1 24 watt 20 inches flouroscent tube lighting. I know its not enough, and I can see the plants turning brown and have holes in it. Where can I buy a 60-100W flouroscent tube for 20 inches hood. I am unable to find a store that has such a tube size.

Please help out. Sorry if I have misposted.

Thanks

 

[Apistomaster]

You may need to consider a different fixture. www.thatfishplace.com has a nice NO dual lamp, T-5 strip light available in a 24 inch and 30 inch.
It is the Coralife Aqualight T5 series
24 inch cat.# 209302 at $43.99
30 inch cat # 209809 at $49.99
I use many of these fixtures from 24 inch to 48 inch and they work fine for low to moderate light demanding plants.
Next steps up are HO T-5 fixture but they cost quite a bit more and I do not think you would be disappointed with the Coralife NO T-5 fixtures.
You state the volume of your tank but not the dimensions; choose a fixture with full tank length lamps.
NO T-5 lamps produce as much usable light as an equivalent length of T-12 or T-8 lamps.
The fixtures I listed use two lamps so you will have all the night you need and at very reasonable prices. These run cool so they can be placed directly on the cover glass.

 

[dw1305]

Hi all,
I'd agree with Apistomaster, 2 x 24W or 21W should be fine. You can get these in 2' (600mm) or 3' (900mm). If you tank is deep and only 20" wide, you need to look at CFL or PL2/4 fittings.

cheers Darrel