the science is great, I need simple advice


Guru Class Expert
Feb 23, 2006
I love reading the science behind why we are throttling back light --but I need really simple advice.

Assuming light on two inch legs, and a 20 inch high and 20 inch deep tank, and assuming I am attached to my L glandulosa and tonina fluviatalus, and especially the nice orange I am getting out of my newly aquired Ludwiga Var. Pantanal.

How much light do I need? and even more important, do I make the change all at once?

do I try a noon time blast ?

my options, unplug all but the 96 watts
swap the 96 watt for the 25 and run that and the 40 watt current fixture

buy a new fixture altogether.

I am dealing with a tank that is a little wider than some.. so I need to consider coverage back to front a bit.. but I would love to trim a little less, still see pearling, ect.

Hoppy sold me on drop checkers
Tom recently helped me pull my tank back from the brink of bba hell by diagnosing a co2 issue.

now.. help me try to rebalance light. I know there is a slight lack in me that makes it tough to rework the science on my own.. but take a little pity.. I am a single mom working full time at a major computer r&d department along side computer phds when I am actually a journalist by trade ... (the kids need more than the avg newspaper job can provide). My poor brain is on overload and I don't have the bandwidth to figure this out on top of the rest.



Junior Poster
Sep 4, 2006
Ontario, Canada.
Hi Sherry, I'm currently experimenting with the same issues. I don't think there is a cut and dry answer. I would try cutting your lights back gradually, and watch your plants.

Only way to find out how your plants will re-act in your tank is to give it a try. I'm doing the same thing right now on two tanks. Keep you posted:)

Tom Barr

Staff member
Jan 23, 2005
Glen's idea is a wise idea as well;)

What I like is a method to reduce and increase light for my tanks, so I use things with lots of low watt bulbs and maybe some MH's that I can raise and lower easier.

That allows you to explore and reduce light when there is any algae issue.

Many suggest stopping nutrients when you see algae, I suggest less light and focus on nutrients/CO2.

Algae are not limited by nutrients nor CO2 in our tanks, you can however, limit them with light, they are light hungry beast.

As you already have L granulosus, you might try working with the pantanal.
It's a weed. L cuba is also nice but not as cherry red, narrow leaf Macrandra is nice as well.

Tom Barr


Guru Class Expert
Feb 23, 2006
btw. Glenc meet Tom, Tom meet Glenc. Glenc grows the most amazing reds without effort. We all want his secret

you took away my algae issues with the co2 fix... I think of lowering light because slowing growth would be nice .. keeping a scape for more than 4 days ect... and because I wonder if the macrandra is just using up some weird micro nutrient.

for an article I have yet ot give apcentral, I interviewed brad from the florida nursery and he said that they can grow mac great as long as there is only a bit of it in a tank. The tanks that are all mcrandra have horrible looking plants. Also in asia, where it was growing in water fed by a running stream it is gorgeous. There is some magical micro nutrient I must be using up even with ei.

I will turn off 40 watts first :)

How do you propogate the Pantanal.. (I have a little cuba. It is nice but not for the red spot.. It looks yellow in my tank :)