Plant lighting

[Tempestuousfury]

I have 2 swords, 3 mondo grass, and a few small java fern plantlets.

By my calculations [(36"x12"x24")/231], the tank is around 44 or something of that sort, and not a 50. However, I was told that it was.

Can you first tell me what the formula is.

Second, how many watts per gallon of light in a sparsely planted (perhaps heavily planted in the future) tank? My tank uses 24" lights, and all i could find at Walmart was a 20 watt bulb that was 24" and hardly lit the tank!

Thanks.

 

[thecichlidaddict]

Can you first tell me what the formula is.

LxWxH / 230.4 - you have a 45.

Second, how many watts per gallon of light in a sparsely planted (perhaps heavily planted in the future) tank? My tank uses 24" lights, and all i could find at Walmart was a 20 watt bulb that was 24" and hardly lit the tank!

Wouldn't it be nice if it were so simple. True, many people love using rules of thumb, but personally I don't think any part of this hobby can be so simpified. First of all, it really depends on what plants you are keeping. Some plants need a ton of light to do well, while others would wither under so much lighting. In addition you will need more wpg then average because your tank is very tall. It is safe to say though that the .5 wpg that you are running now is not nearly enough.

 

[Tempestuousfury]

I replaced it with the one I had the moment I saw that it wasn't working well.

The weaker one said FL 20. The other said FR 20. Not sure what the difference is.

As for not following rules of thumb, I don't either. However, I know that my plants will need lots of light, seeing as how the plants I have need lots of light. Plus, the only plants I'll add later on will be of the same species, seeing as how I only buy from one dealer.

 

[Tempestuousfury]

Can someone please give me a rough estimate? I've got to get that light soon or my plants will get much worse than they are now. (1+ year old bulb in the light fixture right now)

 

[scott1000]

You are going to need a lot of light for because of the height of your tank (24") is really tall and so it'll take more light.

I would recommend at the very LEAST 2 wpg and that probably wouldn't be enough. You might look at something like the Coralife Aqualight Compact Flourescent. The 36" size comes in either a one bulb (96 wpg) or a two bulb (192 wpg) configuration. I would highly recommend you get the 2 bulb one because your tank is so tall.

Once you get your light levels up to spec you should also look into adding CO2, a DIY system would be easy and cheap.

EDIT: Another important note, Mondo Grass is NOT an aquarium plant and it'll die a slow death no matter what the situation. You might want to let your supplier know this! Here's a link to prove it:

http/www.pets-warehouse.com/plant-comps.htm
http/faq.thekrib.com/plant-list.html#blacklist

 

[Tempestuousfury]

I didn't think they'd do well.

I got them from petsmart, so I can't fight big business. They were on sale for $1.oo, so it doesn't really matter. They made good food for my silver dollars when I had them, though.

The fixture can only hold one 24" bulb. So I'd probably have to buy a new one. Don't think I can do that.

 

[scott1000]

In that case you'd probably be best to stick to ultra low light plants like java fern/moss or plastic ones (these "grow" really well in any light condition). These should grow, but will be very slow growing. You might also check into overdriving your bulbs if you're brave.

 

[Great Lakes]

The most handy dandy little aquarium calaulator right here.

GL

 

[Tempestuousfury]

Thanks for the link.

However, do the calculations work for tropical water plants. I know it wouldn't work for stocking levels and heating, but for lights...

Thanks again.

I just might scrap my idea for a well planted tank, or at least one with light-loving plants such as the sword. I have a few Java Ferns in there and I could probably get some more from my 5 gallon tank and/or Petsmart, and that's probably what I'll keep in my tank. Perhaps some Java moss as well?