# Deep tank lighting???



## simpsota (Mar 11, 2006)

I've got a 50 gal tank which is 20" deep (~2-3 inch of substrate). How much lighting should I be using? I've got a two 96W PC bulbs to work with.

Most people have been saying try to keep it around 2 W/g, but I'm thinking I may need more light since my tank is deeper than standard tanks.

I've been running with one bulb for 3 hours (1.9 W/g), then both for 4 hours (3.8 W/g), then back to one bulb for 3 hours (1.9 W/g).

I've been seeing some signs that I might be light deficient as well such as lanky stems with long spaces between leaf nodes, slow growth, loss of red color in new growth of newly added plants, etc...

I'm running the EI method with added pressurized CO2 (using drop checker). 

I've got these (and a few other) plants:
Rotala sp. "green"
Rotala sp. "Colorata"
Rotala sp. "Pink"
Didiplis Diandra
Blyxa japonica
Wisteria
some swords
java fern
green and brown crypts
micro swords

Thanks!!!


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## youjin (Apr 1, 2006)

Wattage and lighting period sound ok even for a 20" depth.

Are you using the Coralife 2 x 96 Watts CF fixture ? Just checking to see what kind of light reflector you have (efficiency). Also, what is the color rating (K ?) of the bulb ?


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## Squawkbert (Jan 3, 2007)

I'm thinking that should be adequate for most plants... if the reflector is good and the bulbs are 6500K, 6700K or the GE 9xxxK bulbs (anything that isn't bright blue/actininc or <4000K should be adequate).


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## simpsota (Mar 11, 2006)

Thanks for the help.

I've got the 36" Current Satellite 96W PCF fixture. It's got one 10,000k bulb and one 6,700k bulb (I replaced the actinic with the 6,700k). The reflector looks like it should be pretty good.

I've got it on it's legs which raises it about 3-4" above the tank top. Would it be worthwhile to take the legs off to get it closer to the water surface?


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## Muirner (Jan 9, 2007)

I say that it would only be worthwhile to do that if you had glass tops on the top of your tank. I think that having the lights to close to open water would spell trouble very quickly.


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## youjin (Apr 1, 2006)

Your lighting sound completely ok even with the legs. I will not worry about it and not change anything on the lights / height / lighting duration.

Maybe, you should elaborate on the EI method you are doing and a pic will help. Iron is required for red coloring in red plants. So far, all that you describe show no issue with the set-up.


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## simpsota (Mar 11, 2006)

youjin said:


> Your lighting sound completely ok even with the legs. I will not worry about it and not change anything on the lights / height / lighting duration.
> 
> Maybe, you should elaborate on the EI method you are doing and a pic will help. Iron is required for red coloring in red plants. So far, all that you describe show no issue with the set-up.


It's good to hear from everyone that keeping the legs on should be OK. The top of the tank is covered, but it would be a hassle at feeding time because I'd have to move the lights to open the cover enough to add the food & ferts.

I'm adding 25ppm NO3 and K (as KNO3), 3ppm PO4 per week (as KH2PO4). I'm adding traces as 10ml (3x per week) of CSM+B as 3tbs dissolved in 500ml water.

I've calibrated my PO4 test kit and it appears to be running around 5-8ppm.
I haven't calibrated my NO3 test kit, but it's definitely not at zero (says it's 40ppm, but I have no idea if that's true)...
CO2 appears to be about 30ppm by drop checker with 4KH sol'n.

I should mention that I've got a nice case of fuzz algae going on right now too (you'll probably see that in the pic).

In the pics you'll see that there are large spaces between the leaf nodes. Plus the Rotala were a nice rosy red when I planted them, the new growth is a light yellow with some very light red hues.


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## RESGuy (Feb 11, 2007)

Well, I don't want to start a completely new thread on the same topic so I'll ask here. 
I have a 20g tall tank that is 24 inches deep and 20 inches long. I want this tank to be low-tech but still be able to keep my plants alive. I won't be having any CO2 except maybe some Excel dosing. Plants will be: Java Fern, Dwarf Hairgrass, X-Mas or Taiwan Moss, and a variety of Crypts. What would be the best light for me? How many watts? K? etc. BTW, I'm on a $142 budget for the whole tank so the cheaper the better!rayer: rayer:


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## youjin (Apr 1, 2006)

simpsota

your rotala look really healthy. I will not worry about it. Keep topping off and it will bush up really well.

Didiplis Diandra - i see it at the back of the pic and growing well as well.

Iron is good to bring "redness" to your rotala and didplis diandra O(nice orange tone)


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## simpsota (Mar 11, 2006)

youjin said:


> simpsota
> 
> your rotala look really healthy. I will not worry about it. Keep topping off and it will bush up really well.
> 
> Didiplis Diandra - i see it at the back of the pic and growing well as well.


Well that's a pleasant surprise and I really needed one ofter the way this week has gone at work!  I hadn't grown this before and when the leaf spacing became much larger than when I planted it I figured it was stretching for light or something. I guess it won't be as noticeable when it all starts to fill in, especially if I start to top it off.

The Diandra was pretty stagnant for a long time. It stopped growing almost immediately after I added it then got covered in fuzz algae. I recently added a bunch of plants and that seems to have kick started it although it's still growing pretty slowly. Once I get some nice growth on it I plan to top it and replant the tops (throwing out the bottoms) to get rid of the fuzz covered sections.



youjin said:


> Iron is good to bring "redness" to your rotala and didplis diandra O(nice orange tone)


I've got some leftover K-Fe liquid fert so I'll start to suppliment my CSM+B with that until I run out, then I'll up the traces when I run out. I'd like to get a little more red in them. My wife keeps asking why I don't have anything red in there... 

Thanks for the help! :mrgreen:


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