[Corrie]

I'm running 3 13w 6500 bulbs in clamp light reflectors...15 inches above the substrate...on a 30 gal breeder

...is that really about 50 par?

 

[Hoppy]

Yes, it is, based on this thread: http://www.plantedtank.net/forums/showthread.php?t=85667&page=2

 

[Corrie]

Thanks Hoppy....actually I was basing it on your post..in that thread

http://www.plantedtank.net/forums/showpost.php?p=904062&postcount=69

I wasn't 100% sure....
I'm breaking all the rules for a low tech, dirted, no CO2, etc tank.

...but, tank's doing great

 

[Rush3737]

Hoppy, you've been such a good help with lighting before, let me ask you something as you'd be better interpreting the graphs and giving advice than anybody.

I have a 29g tank, and am looking for low light, or more specifically, the highest light possible to get away with only using excel for CO2. For the room it's in, if I used one "good" metal vertical housing mounted about 3' above substrate, what bulb wattage would I need to hit my target? What if I used two housings? Finally, what if I just set a housing or two directly on the glass?

I know it's a lot of questions, but I figure you might know an answer in a minute, as opposed to me looking at the graphs for hours and ending up with the wrong answer anyway!

Edit: I figure I'd want to use 2 fixtures (to get better spread), in which case just tell me which scenario you'd suggest and what to get, as I'll do whatever you'd suggest.

Edit 2: The more I look at the one graph, the more I'm pretty sure that if I'm at 15" (on top of glass), I'll surely have too much light with two fixtures. And if I am 36" above (can mount to something at that height easily) I'll surely have too little light no matter what. So, I will find a way to mount at any height if you can tell me at what height and bulb wattage you think a fixture system would work best.

 

[Rush3737]

What's readily available to me (of course I could order anything I wanted online), are http://www.homedepot.com/p/Philips-...iral-CFL-Light-Bulb-E-4-Pack-420091/203248911 and http://www.homedepot.com/p/Woods-60...minum-Reflector-with-6-ft-Cord-0160/204667690.

If I'm reading this correctly:

Then at 17" above substrate I'd have about 35 par, perhaps a little less because of my glass. Sound right?

 

[Hoppy]

Rush, I think you can use 23 watt bulbs, with the reflector rim 2 inches from the top of the tank, and 2 inches of substrate. That gives you room for air circulation to keep the bulbs relatively cool. And, you should have 40-50 PAR light intensity. If any algae problems pop up, you could raise it another inch, or switch to 19 watt bulbs.

 

[Rush3737]

Sounds good, thanks Hoppy. I'll start looking for some 6500k 23 watt bulbs.

Edit: 3 bulbs (1 for stock) and 2 fixtures for under $40.

Gives me a few days to think of how exactly I'd like to hang the lights. Got a couple of ideas and some extra wood, what could go wrong, hah.

 

[GAT]

I ran 2X23watt bulb at 17inch from the substrate for sometime(similar fixture but 10" wide). I had lot of green string algae and sometime black algae spots on the glass. I was doing DIYCO2 but i wasn't changing them very often. DIY CO2 and 13watt bulbs seems to be fine.

Warning: Find a good way to hang the fixture otherwise it fixture will look ugly.

 

[Rush3737]

GAT, good to hear from someone with experience with the nearly exact setup. I already ordered the 23 watt bulbs, but I will count on starting them off a little higher. And yeah, they definitely aren't exactly the greatest things to look at, but my gf is very crafty, so I plan on asking her to find a way to spiffy up the outside of the fixtures to make them look nice.