# Lighting changes affecting crypts?



## gnome (Jan 27, 2004)

Hi, All. 

I'm going to go into more detail than is probably necessary, so I apologize...

I have a 2.5-gallon tank with 100% Flourite. Up until a few weeks ago, I was running an 8W normal-output fluorescent light over this tank. Needless to say, the plants that typically fare better with stronger lighting were never doing too well, but my C. wendtii 'Tropica' was growing beautifully. Each new leaf was bigger than the previous ones and the color was gorgeous. 

Then I switched to an incandescent strip light fitted with one of those 10W power compact screw-in bulbs. It was sort of a PITA because the socket was at one end of the fixture so only half of the tank was really getting more light than before. The other half was basically unchanged. I thought this would work out okay because most of my low-light plants were on one side of the tank while the light-hungry species were on the other. Unfortunately, the one beautiful Tropica crypt happened to be on the side getting more light; I was actually worried that this would make the plant grow bigger than I wanted, but instead, I'm finding that the newest leaves are deformed and stunted, and some of the older leaves are melting or just getting damaged. Incidentally, I had two pieces of C. pygmaea on the "dark side" and one piece that happened to be more on the lighter side. The one piece was actually the best-looking one when I still had the 8W NO flo light and after the switch, it lost most of its leaves and the new growth has been puny and I don't hold much hope that it's going to survive. The two that ended up on the darker side have actually been looking much better. 

When I changed lights, I also increased the dosages of fertilizers I was adding. But I think I was adding too much of something because I was getting a lot of green spot algae. So while my Hottonia palustris has been enjoying this increased lighting, it seems to me that the crypts have not. Do crypts do this? I mean, can I be pretty sure that the lighting change was directly responsible for my crypts getting sick? I'm thinking that maybe I'll move all of the Hottonia to my 10-gallon, switch back to the 8W strip light on my 2.5-gallon and maybe fill the area vacated by the Hottonia with Java fern. Then again, maybe I'm mis-identifying the root cause. Anybody have any thoughts about what I'm seeing? 

Either way, I think I'm going to switch back to the 8W light, if only to see what will happen. I don't like how dim it makes the tank, but right now, I'm not pleased with the yellow/green tint that this 10W PC is causing, either. I may have only needed to get a new 8W tube.

Okay - well, I guess this was more rambling than anything... Thanks for reading. 

-Naomi


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## Chuck H (Jan 25, 2004)

Naomi,

Crypts are notorious for reacting quickly to changes in the environment, so I think your instincts are right on that it is the light change causing problems. From your description, it also sounds like the new bulb has a high amount of green/yellow light, which really isn't all that good for plant growth IME. Do you happen to know the spectral power distribution (that's a mouthful!) for the bulb and if it's full spectrum?

If you want to go back to your old 8W strip and get more light out of it, I recommend the Power-Glo bulbs by Hagen. They're not exactly cheap, but they're dang bright for such a small NO lamp. It has a high color temp (~18000K), but the spectrum seems balanced -- I had some nice plant growth while using it. Hagen also sells a warmer 8W bulb that's suitable for plants, the Flora Glo, but it is not nearly as bright.


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## gnome (Jan 27, 2004)

18000K :shock: ?!?! Are you sure that's not going to cause my glass top to crack? I thought such high temperatures were not recommended for plants. Then again, just a few years ago, people were saying 5000K-6500K was the range you wanted to stay within, and now people are recommending 9325K... This certainly looked better in the comparison photos I've seen. But 18000K? Isn't this typically for SW?

As for this 10W screw-in bulb, it's 6500K and they show a wavelength vs. intensity graph, and it has one peak that's almost at 100 intensity at about 550 nm. The next-highest one reaching 65 is at about 620nm (if I'm reading this correctly). Then there's a broad peak that starts at 390nm, maxes at about 450nm but only reaches 30 intensity, then a sharp peak at about 490nm reaching about 45 intensity. Yes, it looks to me like this bulb is way too green/yellow, at least for my taste. 

What I don't really understand is why, at one point, I was able to grow even light-hungry plants very well in this tank (with an 8W bulb) and this is no longer possible... What's the life on them? I can't remember if I switched out the bulb or if I've been using the same one for the past 2-3 years... Well, seems like it might be worthwhile to try a new one. Before I do, is there any danger of my glass breaking by using such a high-temperature bulb? And could it possibly cause further damage to my crypts before they start looking better again? 

-Naomi


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## dennis (Mar 1, 2004)

Naomi, 

The temp of the bulb is not the actual temperature that the bulb puts out to the touch. The K value of the bulbs is merely a reference to the "look" of the bulb. Therefore, no harm to your glass. 

In general, the higher the k rating, the more blue the light appears. The K rating however is merely a broad reference made up of the overall color the bulb produces. A bulb with a higher K(more blue) may actually have a stronger peak in the red part of the spectrum than a bulb with a lower K rating. I have 2 18K bulbs and one 6700k in my tank and my plants grow like mad. Wu-ha a a a a 

To have a fuller light spectrum is more important than anything else. Basically any bulb between 5000k and 20000K will grow plants. As long as the light spectrum is full then the K(or color the bulb appears to the naked eye) you use is, mostly, personal preference. Now, it is being proven that different bulbs cause different growth in plants (the GE 9325s tend to produce more compact growth with shorter internodes) but in general the K rating of the bulb is not necessarily an indication. Generally speaking though, I have found excellent growth from bulbs in the 6500k to 10000k range. Also use the hagen Life-gro and Power-gro Chuck H mentioned. I personally like the 6700k Life-glo best the color is most pleasing to my eye. Good plant nutrition and CO2 is most important for good growth

My girlfriend has a 5.5 gallon with an 8watt eclipse T-5 bulb and the intensity of the bulb does "appear" to degrade pretty quickly. I assume that you were talking about the regular old florescent tubes and not power compacts. I have a 5.5 gallon with 1 10watt screw in PC bulb and I experience the same dark on one side and light on the other. Everything is growing fine so far. Check out my personal gallery for a pic of this tank. As for the spot algae you mentioned on the glass, I have found it to be a result of low P levels. Do you check for P?

Sorry for the long diatribe about the lights Hope this has helped.


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## gnome (Jan 27, 2004)

Your "long diatribe" was very helpful, indeed! Thank you! The 8W that I've been using and am going back to is a T5. But the one I've been using for just a couple of weeks is the 10W PC screw-in bulb. I had to get a new incandescent fixture for this. I had a feeling that it was going to be a waste of money, but as with all things, I had to see for myself. Maybe I'll find another use for it, someday. 

Now that I know I need to get a new T5 bulb, I'm torn between Aqua-Glo and Power-Glo. Both of these are 18000K, but the Aqua-Glo seems to be more freshwater plant-specific, while Power-Glo says it's good for marine applications as well as for freshwater plants. This is according to the info I was able to find on the Hagen site. Big Al's sells both of these for reasonably cheap, so I might get one of each. I can always replace one of my other 12" lights. 

Thanks again. I never did very well in E&M. Or basic mechanics, for that matter :roll: . 

-Naomi


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## dennis (Mar 1, 2004)

Glad to be helpful. If you can I would try to get either the Lif-glo by Hagen or the Flora-sun by Zoo-med. I have the Lif-glo and I like it vey much. It is a 6700k bulb and very pleasing to me. I have also been recomended the Zoomed bulb as being very close in appearence to the GE 9325(aquaray). As for a choice betwen the Aqua and Power glos I found the Power glo to have a warmer color and the Aqua glo to have more of a blue appearance. Subtle but there. Check out the thread in the lighting(I think) section titled 9325k. It has a nice foto comparison of a few color temb bulbs. While the exact color appearance might differ from brand to brand, you will get a general idea of how different K's look.


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## Chuck H (Jan 25, 2004)

Naomi,

I like to try and change my NO lamps at least once a year (some folks recommend as little as 6 mos), and I'd definitely do that when running a single. Aside from loss of intensity, fluorescent lamps also tend to change their spectral output as they age (phosphors wear out). This will vary somewhat from bulb to bulb.


Dennis,

I didn't realize that Hagen had changed their lineup. They only had four lamps to choose from back in the day -- Power-, Aqua-, Flora-, and Marine-Glo. At least, that's all my LFS sold. Thanks for the heads up. Nicely put about color temp etc. also. I doubt I could've said it better.


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## gnome (Jan 27, 2004)

Dennis,

Looks like I'm getting what I'm getting by default. BA's does not have Life-glo or Flora-glo in 12", so I'm just going to hope that I get what I pay for and go with a Power-glo. It just occurred to me that I need to replace a 15" bulb for my 5.5-gallon tank. For this, I'm going to try the Zoo Med Flora Sun. It says 8500K on the site, and Justin seems to think very highly of this brand, so I'll go for it. Strangely enough, it's one of the cheaper bulbs for this size. I just happened to check the 15" light I have right now, and it turns out that it's a Flora-glo. I remember switching to it a few years back and being somewhat disappointed in how dim it looked. So I guess it's just as well I couldn't find this in 12". 

BTW, I forgot to answer your question about the phophorus levels. I do dose Flourish Phosphorus on a daily basis. When I had the 10W light, I went no higher than 0.25 mL (~6 drops) per day, but before and now (with the 8W light), I'm adding 3 drops. The green spot got really bad really fast only after the switch to the 10W, and it's entirely possible that I should have been adding more Flourish P than I was. 

I think it all comes down to the fact that the change in lighting was extremely abrupt and I wasn't able to balance out the "other stuff" before things started going south. Either way, I still prefer the "uniform" lighting that I was getting from the 8W strip light and I think it'll be best to stick with it.

And Chuck,

I think you're right - the fact that I've been running these bulbs for years-on-end definitely caused these huge changes in the ability to get good plant growth. I didn't realize that they should be changed out yearly or more frequently. I thought I could run them until they started flickering before replacing them  . 

Thanks, guys! Once I change out these bulbs I'm sure I'll see a world of difference... My crypts and I will be indebted to you's...  

-Naomi


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## gnome (Jan 27, 2004)

Hey Guys!

I thought I'd post an update... I LOVE my Power-Glo! Thanks to both of you for the suggestion!

I replaced my old 8W bulb (upon which I discovered it was a Colormax) with the Power-Glo around 4/23. Between then and now, I've actually seen the algae *recede* (especially on my Anubias 'petit' leaves), my Tropica crypt make a mighty comeback, a C. pygmaea suddenly put out some nice, healthy leaves, Bacopa monnieri actually *grow*, and best of all, the Hottonia palustris is looking beautiful - even better than the stuff in my 10-gallon! But that's not all... A few days ago, I noticed that my Sagittaria subulata put out a runner for the first time, AND my plants are actually pearling!!! The lighting is dancing circles around the 10W PC. I'm so happy. It's too bad I wasted $30 for a useless fixture and crummy PC bulb when all I needed was a new fluorescent tube. It wasn't a total waste, as I'm using it now over an experimental tank.

There's definitely a richess in color that was lacking with the PC. Also, it's nice that it spans the whole tank rather than just lighting one side. I'm in the process of cleaning out the 5.5-gallon tank. There was a year's worth of algae and maybe three years worth of mulm accumulated in it, and I'm about halfway done. I'll get it planted again and replace the bulb with the Zoo Med one I got. It's gonna be good. 

Thanks again for all your help! 

-Naomi


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## Phil Edwards (Jan 22, 2004)

That's great news Naomi! Perhaps your 5.5g would make a good emersed growing setup?


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