Fried Rotala Macrandra

[Glenc]

I recently added a 24" Coralife 65 wt CF light fixture to my tank. It was doing just fine as it was but, yet again, I just had to mess with a good thing. Changed nothing else, just added more light. Just had to try 6 WPG. It took a little less than a week to fry my Rotala Mac that was previously growing so nice. I kept waiting to see if it would get better. It didn't. The reds faded to a light pink and the plants just started to melt away. There is definitely such a thing as to much light, or at least to much light to fast. Removed the 65 CF tonight and set up the old, homemade light fixture. Brings me back to 4WPG. Got to test the limits to find out for yourself what they are. Thats what I keep telling myself as I try to nurse my Mac back to health! Here is a shot of my burnt Mac.

 

[LindaC]

Awe, what a shame, sorry to hear that it ruined your R. Macarenda, too bad, but as you've stated, had to try it for yourself. 6 wpg is an awful lot of light though.

 

[Purrbox]

I've got to wonder if it really was too much light or not. Since the amount of light was the only thing that you changed, perhaps the nutrient uptake increased so much that it resulted in one or more deficiencies. Just a thought.

 

[Jchillin]

I have seen similar issues when someone upped their lighting drastically and had the same effect. If I recall, it did have a lot to do with the immediate increase in nutrient uptake as purrbox states.

 

[7Enigma]

Well this is EXACTLY the type of stuff I wanted people to reply in my topic of upgrading lights.

I will be going from ~2wpg to this exact same 65w Corallife light for my 20 gallon high.

I'm going to be really upset if my plants start to die from the high lighting. Here's a question though....

I got the 65 watt with a singe 6500k CF bulb, but also got a replacement bulb that is 10k and actinic. Will this replacement bulb actually be better for the plants since it might have less USABLE light for the plant?

Sorry to hear about your plant...

 

[Purrbox]

7Enigma - If you wanted to go from ~2WPG with your current fixture to ~1.5WPG with the new Coralife fixture, you could use the 50/50 bulb. Of course that would be downgrading your lighting instead up upgrading. Using the full 65 Watts that your Coralife fixture can provide, is only ~3WPG. You shouldn't have any problems with with this amount of light as long as you keep up with the nutrient uptake of your plants.

 

[czcz]

Keep your head up, Glen Suggest an increase in trace dosing for it while maintaining your macro targets under the higher light.

7Enigma, plants can get shocked by higher lighting levels, but again as long as you keep carbon and CO2 in balance, you'll be alright within reason. Notice that Glen's other plants look good, and that he has a command of ferts and carbon, and his example pic is a demanding plant. Learning curve is only steeper and margin of error smaller with high light. 50/50 bulb will limit the curve and give you a nicer margin for error, but will also have your tank much closer to medium light than high light.

Only my 2 pennies, of course.

 

[7Enigma]

7Enigma - If you wanted to go from ~2WPG with your current fixture to ~1.5WPG with the new Coralife fixture, you could use the 50/50 bulb. Of course that would be downgrading your lighting instead up upgrading. Using the full 65 Watts that your Coralife fixture can provide, is only ~3WPG. You shouldn't have any problems with with this amount of light as long as you keep up with the nutrient uptake of your plants.

That's a 65watt CF, not NO. By the modified wpg rule (which makes complete sense), that 65 watts would actually be 114, so in a 20gallon tank that would be 5.7wpg or about 6 as mentioned in the original post. That's why I was concerned.

czcz, did you mean nitrogen and CO2? With that 50/50 bulb, how many watts is that actually (of usable light for the plants)? I originally thought that the CF bulbs had under a year lifespan like the NO bulbs, but now see its 2 years at the minimum. I'll try it with the 65watt 6500k bulb first, but if the 50/50bulb puts me at 3-4wpg but makes the fish/plants stand out better from the actinic, I might go that way (especially since it won't show quick nutrient deficiencies so fast).

 

[Glenc]

Thanks guys. Great advice czcz. Thanks. Purrbox, you are also correct as since adding this light I cannot keep Nitrate or PO4 levels up in my tank. They are usually pretty low anyway, but they were bottoming out every day by the time I got home from work. 7Enigma, The 65 watt coralife fixture alone didn't toast my Rotala mac. I had a 24 Watt Coralife T5 fixture and a homemade fixture on my tank, giving me 4WPG. Everything was great. I removed the homemade fixture and added the 65 watt Coralife. I had the 65 watt Coralife and the 24wt T-5 Coralife fixture running together. That's alot of light. Over 6 WPG using Wizzard's theory. It was very bright. That's what fried the Mac. It may have adjusted to the higher light in time but I pulled the plug. It was looking pretty bad and I didn't want to chance losing all of it. It is a tough plant to grow, and it was the only one to reject the new high light. My green plants however are GREEN and growing like weeds. I may use the 65 watt Coralife again on it's own, but for now, I'm going back to my tried and true light set-up to try to reproduce my original successful lighting recipe, 24 watts T-5 and my homemade T-6 fixture. Hope to get my Rotala Mac healthy again. Don't be afraid to use the Coralife 65 watt fixture. Keep the 6700k bulb in it. It is excellent. Just maybe use it on it's own.

 

[czcz]

7Enigma, sorry, nutrients (not only nitrogen) and CO2.

First row is for a 50/50 bulb. Second is assuming 25% of the 50% actinic is usable (purely a guesstimate). Most important is lumens/sq in, which you can cross reference vs established tanks here.

7Enigma's 20H
          Eq T12 wpg  Lumens   Lumens/sq in
32.5w CF        2.19	2580.5	 8.96
40.6w CF        2.74	3223.64  11.19
65w CF          4.38	5161	  17.92

And for fun, Glen's.

Glenc's 20H
          Eq T12 wpg  Lumens   Lumens/sq in
24w T5          2.12	2496	 8.67
65w CF          4.38	5161	17.92
24w T5+65w CF   6.5	 7657	26.59

 

[Lonewolfblue]

My L. repens is starting to fade away like yours is in my 26G with 65W lighting. Maybe just too much. I'm thinking of putting the 50/50 bulb in that cake with the fixture to see if it will come back, as I'm not injecting CO2 in that tank, just Excel.

 

[7Enigma]

czcz and glenc,

Thanks for the replies. czcz, how are you getting 4.38 for our 65w corallife fixtures? From the modified wpg theory thread 1CFwatt is equal to 1.75watts of NO light, so that 65w would be closer to 5.8wpg by my calculation. I'd actually prefer if my 65watt will only be 4.38wpg, but would like to know how you came up with that value.

The 2.74wpg for the 50/50 bulb is also great since while still not high light, is great medium light and might help the coloration on the fish in the tank. I'm thinking about using the 6500k bulb mainly, but when I go on vacation for a week or so, will switch back to the 50/50 bulb so my nutrients don't bottom out while I'm gone.

 

[czcz]

After simple averages and then quick and dirty deviation for lumens/watt on a series of bulbs,1w CF is more like 1.35w T12 NO. Sample bulbs and calcs are further down Ozz's thread and his website article, if interested.