High light from many bulbs?

[JustinKScott]

At a couple of dollars each, why can't we buy many 100w 6500k daylight cfl twisty "incandescent replacement" bulbs to reach our grow requirements?

Example I have a 180gallon planted, and I have 6x 54w t5ho bulbs. Each bulb is $30 and must be replaced every 6mo. With the current setup I have 324w of light, which is not even 2w/gallon.

When I replace my bulbs here within a month, what's stopping me from replacing them with 10x 100w 6500k cfl "incandescent replacement" bulbs for a total of 1000w and nearly 5w per gallon? The cost of of 10 bulbs is roughly the same as one of my t5ho bulbs... Why would that not work?

 

[mfdrookie516]

Because WPG means nothing in small tanks and large tanks. You've probably got enough light to grow about any plants you want already.

 

[fort384]

Rook is right on.

Also, 1W of T5HO produces much more PAR (when reflected properly) than 1W of CFL. What you are asking to do would work... But it would be a colossal waste of electricity and money on a 100 bulb cfl fixture. It would also take a large circuit to run that much light. With your current setup there aren't any aquatic plants you can't grow, assuming you are running co2 and dosing Ferts.

 

[JustinKScott]

That's what is was worried about, but I can't find anything on wavelengths produced by these cheaper bulbs.. Like ge reveal for example, no wavelength info.

What about the really large cfls? Like: http://americanaquariumproducts.com/PowerCompact.html


I'm shifting over to compressed co2 this week as I can't get any noticeable ph drop from my yeast based system. I only need a needle valve, I have everything else.

 

[fort384]

You would need to run a dozen or more 2L generators for a Diy system to work on a 180. Pressurized is definitely the way to go.

 

[doogle]

you should get more life from your t5's unless you are really overdriving them. more like a year or 18 months, if you stretch. $30,what are they geisseman bulbs?

 

[JustinKScott]

What's a geissman bulb? They seem to be about 30 plus shipping.

Why do you say I should get a year out of them? I thought they magically wore out after 6 mo and need replacement. How would I know if they are still ok?

 

[fort384]

I run t5ho and Cfls for 18 months.

 

[BigJim]

fort and mfd are right. The Wpg guidelines (note guidelines, not rules) are used because the vast majority of hobbyists don't have expensive PAR meters to figure out how much usable light they actually have.

If you're looking to avoid bulb replacement costs, look at LEDs. They're directional so you don't have the reflector and restrike issues that go with fluorescents. For $360 or a years worth of bulbs, you could fab up a very serviceable LED fixture, ditch bulb replacement for a long time, and cut your electricity bill.

 

[fort384]

Good call on exploring LED as an option. While they have been around for years they are still relatively new to the fw planted scene and I have no personal experience with them so I often overlook them as a viable alternative. Bigjim has a great build thread linked in his signature if you want to see what you might be in for on a DIY build.

 

[JustinKScott]

I've looked at their spectrum before some of them have very strong power rating right in par range.

I can't imagine it'd be hard or expensive to set it up from scratch if you knew which LEDs to buy. You'd need a little math to find desired voltage drop on the LEDs and a consistent transformer.

 

[JustinKScott]

Read jims thread.. I have to consider doing this myself. I'm a EE so this is a real option for me.

Wouldn't have thought the bulbs would get too hot.. How hot are they? Can you send me a link?

 

[BigJim]

LEDs that will work for a planted tank aren't cheap. Mine were nearly $5 a piece, but I was trying to cram a lot of light into a small tank. There are price breaks if you're buying in quantity too.

LEDs are current driven. A source with constant current is preferred over a source with constant voltage.

 

[doogle]

you have a big startup cost for l.e.d.'s that are worthy for growing plants. geissman are high quality bulbs...(expensive)....anyway, if they turn on they work, they lose a little power in months, weeks if overdriving... but they will still work.after a year or year and a half, buy a new bulb and compare how much brighter a new one is next to a older bulb.