I Thought Lighting Would Fix The Problem!

[notg2009]

Hey everyone,
I have a 29G Marineland planted tank. I used to use the stock LED unit but decided to upgrade to better lighting in order to get better plant quality. I dose with Seachem Flourish and Flourish Excel per bottle instructions.The tank is cycled and I dose with Seachem Stability when doing water changes. I have regular gravel substrate and have the following plants:
 
Amazon Sword
Anacharis
Anubias
Elodea
Java Fern
Water Lettuce
1 unknown plant!
3 driftwoods
 
Here is the light that I use: http/www.petco.com/product/113078/Coralife-Dual-Fixture-High-Output-T5-Aquarium-Light-Fixture.aspx?CoreCat=OnSiteSearch
30" L X 5.1" W X 2" H 
1 - 30" actinic bulb 31 watt 
1- 30" 10,000k bulb 31 watt 
 
It has been one week and I thought I would see dramatic changes in plant growth but not much has changed. Also I have noticed that since the light upgrade, my tetras have gone further lower in the tank and do not swim up much. Is this too much light? Should I get the 24 inch light?
 
I really appreciate suggestions.

 

[notg2009]

Also I think now I have black brush algae!
 
Photo: 
https/onedrive.live.com/redir?resid=7CE4769A09BA23B5!233507&authkey=!AAu80IsbPCOq9f4&v=3&ithint=photo%2cjpg

 

[Byron]

The main issue I see is the light, both the intensity and the spectrum.  I'll deal with spectrum first.
 
The tubes you are presently using are intended for marine tanks with corals, as these are both very high in the blue with little (if any) red.  Aquatic plants need red and blue to drive photosynthesis, and there is some evidence now that green also helps.  For this, tubes with a Kelvin around 5000K to 7000K are best.  With a single tube, I use 6500K and with dual tubes I mix 5000K and 6500K.  The "daylight" 6500K tubes are high in red, blue and green and studies have shown plants respond best to this spectrum, all else being equal.
 
The second part of the lighting is the intensity.  Two T5 tubes will be way more light that the plants can possibly utilize, but so will two 24-inch in T5.  If this was a T8 fixture, you could make it work by adjusting the duration.  But with dual T5 tubes, you are really fighting a losing battle.
 
The plant lack of response is due primarily to the spectrum.  The brush algae is certainly due to both spectrum and intensity.  This high blue light is known to benefit algae, as unlike higher plants, algae can make do with almost any light.
 
Another thing to keep in mind though is that changes in the plants due to changes in lighting or fertilization usually takes longer than a week to become obvious; I tend to give changes at least three weeks before I conclude the change was or wasn't helpful.  However, in your present situation, I would certainly change the lighting now, as this is not going to improve.  And yes, this bright lighting does affect forest fish, significantly.
 
A dual tube T8 fixture will work, or a single tube T5 could work.  Which raises a question...is it possible to remove one of the present tubes and still have the other light?  This if possible will solve the issue, with a new 6500K tube.
 
With the suggested light, you should be OK with the Flourish Comprehensive Supplement.  The Excel is a product I will not put in my fish tanks; this contains glutaraldehyde (and water), and this is a highly toxic substance.  Even at recommended doses, it will usually kill some plants, like Vallisneria, but if it should happen to be overdosed, it has the ability to kill fish, plants and all bacteria.  It is used in hospitals to disinfect medical instruments, which gives you some idea of its risks.  Yes, I know some people use Excel, but I see no purpose in putting such a substance in an aquarium.  This is just my view.
 
Just for illustration, I will add some photos of my 29g in various aquascapes over the past five years.  This tank has one 24-inch T8 17w tube, a Life-Glo 6700K.  This is about the minimum over this tank, but even so it does show what is possible.  I have also been using Flourish Comprehensive Supplement once weekly.
 
Feel free to ask questions.
 
Byron.

 

[notg2009]

Thanks for the great info. Do you have any suggestions for a certain model/brand?
Also how can I get rid of the algae? i already disconnected the light and went back to the stock LED. I also have a pleco.

 

[Byron]

Thanks for the great info. Do you have any suggestions for a certain model/brand?
Also how can I get rid of the algae? i already disconnected the light and went back to the stock LED. I also have a pleco.

 
You're welcome.  On the algae, you cannot remove what is already present (and yes, that in the photo is a form of brush algae, which pleco will not touch) but when the balance (light/nutrients) is reached for the plants, the aim is to not have the algae increase, so we work for that.  Reducing the light as you've now done should help with this.
 
Which brings us to the light.  I have no direct experience with LED, but if you post the data on this fixture other members may be able to offer assistance.  I am still using T8 fluorescent lighting over most of my tanks, with incandescent (screw-in bulbs) over the 10g and 20g with the compact fluorescent daylight 6500K bulbs.  The latter is fine over small tanks, but can get clumsy over larger, so I would suggest fluorescent or LED.  BTW, have you removed one of the T5 tubes to see if the other will still light?  This depends upon how the fixture is wired, but some will.
 
Finding T8 fixtures for aquaria these days is next to impossible, as the advances in T5 and now more-so in LED are what aquarists prefer.  I found this out two years ago when my five-foot T8 fixture gave out, and I ended up getting a dual-tube shop fixture and installing it in the housing.  That is another possibility here too, if you can find them in 2-foot lengths.
 
Byron.