Lighting question

[619andyp]

I was looking to get new bulbs for the fixture on my 72 gallon planted Discus tank. It has 4X65 watt power compact lighting. From what I understand, everyone says 6700K is ideal for plant growth. I really like the way the 420nm Actinic bulbs make the fish pop. I was thinking of getting two of the 6700k and two of the either 420nm or two 50/50s. I think this will be fine. What I want to know is what everyone on here thinks. Should I do all 6700k, or 2 6700k and 2 420nm, or 2 6700k and two 50/50s (10000k/420nm)?

[SoCalBoo]

Ideal kelvin spectrum for growth is in the 6000s. 10,000k will provide growth, just not as much. You'll get no growth out of the actinics. But in many tanks, the aesthetics of the 'blue' light are nice. Just a personal preference - how much plant growing power are you willing to sacrifice for the 'cool' appearance? A couple other important factors - how tall is the tank, what type of plants are you trying to grow, and what is your substrate?

[619andyp]

Thank you SoCalBoo for the input.

The tank is a 72 gallon bowfront. It is about a foot and a half tall. Maybe a little more.

I have Swords, Anubias, Octopus plant (Crinum Calamistratum), Java fern, and some otehr stuff I forgot the name of. Grassy looking stuff, mostly. Maybe a foxtail or something too.

I am using Substrate I mixed my self from PetKingdom. It is roughly 70% sand and 30% of the black substrate they sell to mix. They told me this ratio was best. Looking back I wish I would have bought eco-complete.

I don't have Co2 but thanks to Dave (ocean?) I now use Flourish Excel also. Plants have never looked better.

I would really like to use actinics so I guess I would want to use two 65 watt 6700K and two 65 watt actinics. Will that work and what is better? True actinics or the 460nm. Or is this a bad idea and I should stick with all 6700k?

Just looking for your guys opinions.

[acbaldwin]

I prefer a mix of 6500k and 10000k. Aesthetically ~8000k is ideal (for me).
That said, I'd go with 2x6500k and 2x 50/50 if you want some actinic.

[SoCalBoo]

my last pc set up was 2x6500k, and 50/50 with 10,000k and actinic. worked nicely. experiment with bulb placement. if you've got a blue background I'd start with the 50/50 in the front. keep in mind that you are getting bluer from about 5000k upwards, so with the 6700k and the 10,000k, you already have a lot of blue spectrum. I am wondering if it truly is the actinic or the other bulbs that were giving you the 'blue pop' you liked before. I only mention this because it is a shame to give up one of your 4 bulbs to actinic if it isn't doing anything for you, aesthetically or with plant growth.

PK really touts that black cinder, which is most likely the black stuff you bought. Truthfully, the plants you bought need such little nutrients from the substrate (if any), you are fine with what you have. I would also add that if you aren't dosing with CO2 or throwing heavy amounts of halide or t-5 light, might actually be good that your substrate isn't super fortified.

Personally, I'd experiment with dosing minimal amounts and moving upwards until I found the 'sweet spot'. I would also experiment with using just 2 of the 4 bulbs, and would opt for the 2x6700k bulb combo first. You'll save on energy, bulb usage, and may avert an algae outbreak. As well, I've always found that discus shy away from bright light anyways, so having a ton of light on a tank is often wasted on them. If you find you really want to run a ton of light, you can always dose the discus black water supplement (using mopani or malaysian driftwood works nicely, as the wood leeches into the water).

Just some ideas from my personal experience. As always, free advice is worth every penny you paid for it...

[619andyp]

Just some ideas from my personal experience. As always, free advice is worth every penny you paid for it...

I agree, and really appreciate the input. Thank you SoCalBoo & acbaldwin for all of the great info!

So, I was running one 48" t5 and everything was barely growing. Then I started dosing with Flourish Excel which is a synthetic Co2 and everything really took off.

I saw a good deal on here for a 48" 4X65watt PC fixture and snatched it up. I thought more light would equal more growth. When I replaced the one T5 with the new lights I couldn't believe how much more colorful my fish looked. The entire tank seemed to really pop. I am pretty sure the bulbs are way beyond needing replacing too (although I asked the guy I bought it from and he didn't return my PM so I don't really know). Currently there is 2X 10000k and 2X actinics. I had thought it must be the actinics causing this new popping effect.

I agree it will be shame to give up one of my 4 bulbs to actinic if it isn't doing anything for me, aesthetically or with plant growth. Because of all the great advice here I think I will get two 10000 and two 6700 and see how it goes. If I don't like it I will try something different the next time.

Thanks again SoCalBoo and acbaldwin.

[Dan Knowlton]

I'm running 4x65 6700 bulbs - works well for me. Also, CO2 is on for 7 hours per day with fertz and trace added.

Dan K.

[specvjeff]

Coralife has a really nice bulb called a colormax bulb. It's half 6700k half red. I would do 2 of those and two 50/50 (10k, actinic) bulbs. This will help with plant growth and really make the colors of your fish pop!

[619andyp]

Coralife has a really nice bulb called a colormax bulb. It's half 6700k half red. I would do 2 of those and two 50/50 (10k, actinic) bulbs. This will help with plant growth and really make the colors of your fish pop!

I ended up getting two 6700k plant bulbs and two 50/50s. When these need replacing, in like 10 months, I will try the 50/50 red/6700k.

[drainbamage]

One thing that I try and point out to folks is that as much as the 6700's will grow your plants the best, if the ack's or 50/50's make you enjoy your tank more due to looks, you'll provide better maitenance to the tank. This means your tank will look a lot nicer than the yellow 6700k tank with plants growing galore but no inspiration on your part to keep things maintained.
Also, bulb location does matter to a small degree. If you've got the lower light stuff (like the crypts) near the front of the tank, and the higher light stuff (grassy stuff = valsineria usually) in the back, put the 6700's in the " back " of the fixture and the 50's up front. It'll give you the looks you like plus the plants will get more of the focus they need.
So what do you think so far of the combo you have running?

[619andyp]

One thing that I try and point out to folks is that as much as the 6700's will grow your plants the best, if the ack's or 50/50's make you enjoy your tank more due to looks, you'll provide better maitenance to the tank. This means your tank will look a lot nicer than the yellow 6700k tank with plants growing galore but no inspiration on your part to keep things maintained.
Also, bulb location does matter to a small degree. If you've got the lower light stuff (like the crypts) near the front of the tank, and the higher light stuff (grassy stuff = valsineria usually) in the back, put the 6700's in the " back " of the fixture and the 50's up front. It'll give you the looks you like plus the plants will get more of the focus they need.
So what do you think so far of the combo you have running?

Drainbamage was a late 80s high school punk band from Virgina that Nirvana drummer Dave Grohl was in. I wander did you name yourself after them or is it just coincidence?

I like the light combo so far. I have the 6700ks over the middle of the tank and the 50/50s in the back. The plants are still growing. Even better, the fish really pop like they are under a black light. People used to ask me occasionally if my discus were saltwater but now I get asked all the time.