Best lighting for 20 gallon 24L x 13W x 16H

jcali10, 2 T5s with Tek II reflectors is actually way more light than you would think. The reflectors push tons more light down, so you can use less bulbs. If the projection of light from the reflector is wide enough, I'm 100% sure I could get away with 1 22 in. T5 bulb with a 24 in. Tek II reflector on the 20g.

Given the fact that the tank is not deep, it's possible it could still require CO2 even with one bulb + reflector. If I stick with a Seachem Excel only regimen, 1 T5 with Tek II reflector will certainly be more than enough light.

The tougher thing to figure out is how to handle light for the 135 gallon setup, which is a 24 in. deep tank. It is possible with 3 inches of substrate that I could get away with either 2 80W bulbs with Tek II reflectors (which would leave the ends not perfectly covered), or 4 39W bulbs with Tek II reflectors. For both tanks, I'm not going for fastest growth, but rather stable steady growth of a wide range of colorful plants. I want to be able to grow red plants, but don't care to grow the most light-hungry species. I was able to grow beautiful red plants with 4 32 watt T8 bulbs with reflectors on our 75 gallon.

BTW, I never buy fixtures, I've always retrofitted my own lights, reflectors, end caps, etc., which is much cheaper.

I agree with your point about reflectors, high quality reflectors will put more light on your tank. I've read about restrike too. I better understand where you are coming from now. I'm not trying to be critical of your ideas, I sincerely was just trying to be helpful.

It seems to me like you have abandoned the watts per gallon rule, which is simple and useful because people can easily relate to wpg when discussing their tank paramaters. So you've adjusted the WPG rule to take into account better reflectors, where 1.7 wpg over a 75G tank is equivalent to what exactly? Have you calculated that? or are you just making a judgment based on past experience, which is fine also.

Apparently you already know from personal experience, what works for you regarding light intensity and organic CO2 supplementation.

For your 135, regarding light penetration and depth, I think if the light is 30 inches or more from the substrate, you may need to consider stronger light, such as metal halides. I'm just guessing here. You'll have to do some research. There are some very lengthy, technical, and in-depth posts on light parameters, that provide everything you always wanted to know about light but were afraid to ask, written by folks that are actually knowledgable in that field.

BTW, I only buy fixtures.

When planning a new set up, we always want to get it right the first time. I understand that it is important to make the correct purchases. Mistakes can be costly. That's why we share our thoughts and look for feed back. So good luck.

Regards,
Joe

Hi Joe,

I never took your post as criticism - every bit of experience and knowledge contributed makes any project better. I learn a little something from every post, and there is so much yet to know. See my post - there's not a critical line in there. I was only thinking out loud about light requirements. I can't stand it when posters in any forum flame people just for offering their experience or disagreeing. I've learned things even from reading the newest newbie post.

I've never done any calculations, just basing off my experience. See the post I just wrote on what I learned from my 75 g going from T8 bulbs to better T8 plant bulbs to mylar in my hood to DIY 98% reflective parabolic aluminum reflectors. I was getting high quality growth at far less than standard WPG guidelines, saving electricity and reducing heat output - something all of us should be interesting in.

In discussing the 135 g light requirements in that thread, some posters with experience with T5 and Tek II reflectors think that I could even get away with 3 T5 80W bulbs with Tek II reflectors, staggered across the midline of the tank.