Difference in T5 HO Bulb Frequency

[Old Scales]

My 29g tetra tank is heavily planted. Among the plants, I have dwarf baby's tears on the bottom front of the tank. They have just sat there staying green but not growing. My light for the last four months has been a T5 HO flourescent with two 24w bulbs. One is a 6700k and one was a 5000k. My light sit 17.5" above the substrate. I figure I have about 1.9 watts per gallon which is at the lowest side of medium light I think.
The fellow at a newly found & very nice fish shop told me the 6700k frequency penetrates the water a little better than the 5000k. So I put the light as both 6700k. My DBT has now gotten a little greener and is starting to spread, albeit very slowly.
This makes sense as I remember SCUBA diving in Cosomel and the deeper we would go the bluer the light from above became.
I have ordered a quad bulb T5 HO fixture with timer and night LEDs that will get me where I want to be on light. 96w. It should be here Wednesday. So if any out there are at the low edge of medium light this 6700k thing might help. I don't know about bulbs any higher than 6700k as I have never used any higher. Life & Luck, OS.

 

[aqua_chem]

It's true that blue light penetrates water better than red light. However, this only starts to become relevant at depths of more than 10 feet or so. It's certainly not a factor in a much shallow tank like what you have.

Do you have CO2? Are you dosing anything? Plant growth is limited by the least available resource. You have plenty of light, but you're probably lacking ferts and CO2. Adding more light only increases the imbalance and will likely lead to headaches down the line due to algae. More likely than not, your problems are stemming from a CO2/fert issue and not light.

 

[Old Scales]

I use presurized CO2 at a rate of 1 bps. I don't have a drop checker yet. Use liquid carbon also at 3 ml. every morning. Dose Flourish 2x week @ 3ml. and Yamato green and 2 ml every morning. My PPS-pro and bottles will be here Wednesday. So you think my current light is enough? I was under the impression 2.5 to 3 WPG at +/- 6 hrs a day would be better against algae. My 6th day tests(right before PWC 33%) is always 12-15ppm NO3 and PO4 3- is .25 -.50ppm. Thanks for your reply. Caudially, OS.

 

[aqua_chem]

If someone tries to give you advice based on WPG, rest assured in knowing that they don't know as much as they think they do. Watts is just a measure of energy usage. It doesn't tell you have efficiently that energy is being used, or how much of the light that is made. An odyssea fixture and a Tek or ATI fixture use the same amount of energy, but the latter fixtures could potentially double the amount of light. Add to that distance for substrate, etc, and it's a really bad system.

Who makes your lights? How long have they (the plants) been in your tank? Algae?

 

[Old Scales]

I am sure I have imperfections in my total set up and methods. The more I reasearch, the more I find where I need to adjust. The old PDCA methodology of problem solving. One lesson learned is that the Zoo-med fixture I have now is not nearly the best out there. I did try to optimize the situation by going to Guiesman bulbs. This fixture does not have the best reflectors for sure. However, my observation about the better plant growth is based on the only change being the bulb replacement. I kept all the baseline parameters under the same controls.
Thank you for your response. I value you and Rivercat's advice greatly! You both have helped me get on the right path to advanced plant culture. LOL Keep me challenged and thinking. It will help me learn, I love it!
Looking forward to more spirited discussions my friend. Sincerely, OS.

 

[MMantelli]

I also recently acquired some dwarf baby tears and thanks to one of our fellow members also the plant guru I learned a recipe for dbt success. High lighting+co2+good ferts+patience/time=growth. As they do grow slow. But for your lighting question mabey this will help.

http://www.aquariumadvice.com/forums/f60/the-best-website-ive-found-for-light-info-255755.html