Why do people run 6500K bulbs?

[xiaoxiy]

After running 2 6500K and 2 True Actinic bulbs in my 8 bulb mix I removed one of each and replaced with purple+ bulbs. While I liked the previous look, over time the visualized colors began to fade and brown out despite not having any sort of alk swings or nutrient bombs. I still am enjoying the spectral benefits of the 6500K and the actinic but now the tank is visually a lot more appealing. There’s more daytime fluorescence and some new colors are now coming out that I had previously never seen on some acros. Neat to see.

How long did you have it running for before things started browning?

 

[Bpb]

Read the question wrong at first. I’d say the browning was a gradual shift over the course of about 5 months.

All acros haven’t made any groundbreaking turnaround but a handful have started to display colors other than brown in the short 2 weeks since the bulb change over

 

[xiaoxiy]

Read the question wrong at first. I’d say the browning was a gradual shift over the course of about 5 months.

All acros haven’t made any groundbreaking turnaround but a handful have started to display colors other than brown in the short 2 weeks since the bulb change over

One thing I was worried about was browning of corals under the 6500 light. Maybe I'll swap one out for a P+ or a C+.

Here's how it looks currently with 2x GE6500s.

 

[Bpb]

I think you’ll like what it does. Don’t get me wrong. I LOVE the ambient look of a 50/50 Actinic/6500K mix, I just didn’t love what it did to the acro colors. I do like the natural shallow water real life look of the sand and rocks. Just missed vibrant acro colors. They became too muted

 

[xiaoxiy]

I think you’ll like what it does. Don’t get me wrong. I LOVE the ambient look of a 50/50 Actinic/6500K mix, I just didn’t love what it did to the acro colors. I do like the natural shallow water real life look of the sand and rocks. Just missed vibrant acro colors. They became too muted

Were the colors muted because of the visual spectrum they were under, or were they legitimately browning (i.e would be muted/browned even if you threw them under actinics immediately)

 

[Bpb]

They were legitimately browning. Many acros lost their purple tips and my blues faded to an olive drab. Fluorescence under dawn dusk actinics disappeared entirely on acropora (lps remained fine no change in those. JUST acros). My red planet and green slimer acros were never effected and looked about the same either way. Most heavily effected were the Cali tort, purple efflo, Hawkins echinata, pink lemonade, blueberry fields, and mega man acros. Those all started to turn the same olive/brown color under both daylights and actinics

 

[xiaoxiy]

They were legitimately browning. Many acros lost their purple tips and my blues faded to an olive drab. Fluorescence under dawn dusk actinics disappeared entirely on acropora (lps remained fine no change in those. JUST acros). My red planet and green slimer acros were never effected and looked about the same either way. Most heavily effected were the Cali tort, purple efflo, Hawkins echinata, pink lemonade, blueberry fields, and mega man acros. Those all started to turn the same olive/brown color under both daylights and actinics

Super interesting! I wonder why this happened.

@Battlecorals runs 4 GE6500s, if I remember right, in a 8 bulb ATI fixture. Has anyone else experienced similar browning from running "too many" GE6500s? @jda?

 

[dricc]

I have a t5 and metal halide hybrid lighting. What if i ran 2 6500 iwasaki bulbs and two blue plus and two pure actinics. Would this be the best of both worlds? Thanks

 

[jda]

I have never had anything but better colors and growth with 6500K T5 bulbs.

6500K Halides are pretty strong. Two B+ and two TAs will not likely be able to overcome these. I do use a single 6500K in my frag tank to raise clams and frags where i do not care if they look yellow, but I would not likely use them on a display... 10K might be a better choice.

 

[Bpb]

Super interesting! I wonder why this happened.

@Battlecorals runs 4 GE6500s, if I remember right, in a 8 bulb ATI fixture. Has anyone else experienced similar browning from running "too many" GE6500s? @jda?

Yeah. He is a big fan of warmer spectrums I know. I don’t have any reasonable explanation. I know paletta and Sanjay both tout amazing colors under iwasaki 6500K bulbs as well. I won’t pretend to compare my situation to theirs. They’re all on a professional level with decades of experience with very large (or in Adams case, massive) bodies of water they’re working with, with extremely stable mature systems. I can’t fairly compare a 3 year old 90 gallon tank to a 10 year old 500 gallon tank. Experience level and system specifics are just too different.

I will not say for certain that the 6500K bulbs were 100% to blame. But changing out one of those plus an Actinic for purple+ bulbs has caused improvements on my growth and color. I’ve had to tune up my calcium reactor every two days to account for growth over the last few weeks now and that’s really the only change I made. Bear in mind I do still run one 6500k and it is directly over the bulk of the acros in the tank.

I also reduced my light level. Previously I would run just a blue+ and an Actinic for dawn dusk for an hour with all 8 bulbs for 8 hours. Now I use 6 bulbs for 10 hours with all 8 bulbs for only 4 hours in the middle. Shorter full intensity period, but longer and more intense dawn dusk. I don’t know what kind of difference that made if any. But whatever I did my colors improved as well as growth

 

[xiaoxiy]

Alright. I think I've made a decision.

I'm going to run a 12 hour and 30 minute photoperiod. There will be a 1 hour sunrise and 1 hour sunset. Immediately after sunrise, my T5 bulbs (2 Coral +, 2 GE6500) will kick on for a 4 hour burst, blanketing my corals under 3-400 PAR. After which, the T5s will turn off, and the LEDs will be running a blue spectrum (AB+ like) for the duration of my photoperiod, giving my corals ~100 PAR for the duration of the photoperiod (6.5 hours).

Anyone see any major issues to running a 12.5 hour, low intensity photoperiod with a 4 hour burst? If not, then I'll update ya'll in 6 months as to how the corals have responded.

 

[BigJohnny]

Super interesting! I wonder why this happened.

@Battlecorals runs 4 GE6500s, if I remember right, in a 8 bulb ATI fixture. Has anyone else experienced similar browning from running "too many" GE6500s? @jda?

No he actually runs geisseman tropics not ge 6500k

 

[xiaoxiy]

No he actually runs geisseman tropics not ge 6500k

Good catch!

 

[mcarroll]

After running 2 6500K and 2 True Actinic bulbs in my 8 bulb mix

What were the other four bulbs in the combo?

What was the combo BEFORE the 6500K's went in?

What were nutrient levels like? What was flow like?

Did either nutrient levels or flow go through any changes through the same period of time?

 

[Bpb]

What were the other four bulbs in the combo?

What was the combo BEFORE the 6500K's went in?

What were nutrient levels like? What was flow like?

Did either nutrient levels or flow go through any changes through the same period of time?

Good questions. A rough timeline

2 years
4 blue+
2 True Actinic
1 6500K
1 coral+

6 months
4 blue+
2 6500k
2 True Actinic

3 weeks (to current)
4 blue+
1 6500k
2 purple+
1 True Actinic

Been running the same flow profile on my powerheads since I got them two years ago (2 tunze 6105, and i hit 100% power often, but the general flow is varied and turbulent)

No changes to feeding or nutrients otherwise.

NO3 has stayed pretty stable in the 2-10ppm range

PO4 stays around 0.07-0.1 kinda depending how heavy I feed or if I miss a water change (15% weekly is normal, but life happens occasionally)

 

[mcarroll]

So that's the three setups, in order from top to bottom just to help me visualize your changes. (tough to tell the coral+ from purple+ unless you look close)

Initially all I could say is that these appear to be the same kind of changes that get's LED-tweakers into trouble.

These may or may not be some interesting details:

• 6500K bulbs (should) carry more PAR than the blue bulbs, so that's one tweak.
• They also carry a lot more green and red wavelengths, which is another tweak.
• The corals all have to get used to both new aspects. (The good thing is that you have decent nutrient levels.)

Were there any significant changes to the photoperiod at the same time?
Was it all lights on for 12 hours for each config?
Look for additive "problems" here if there was any increase in photoperiod.

BTW, was there anything wrong with the first bulb configuration? Why the changes?

 

[Bpb]

More recently I decreased the length of full intensity but otherwise it was always 10 hours. I know it’s a lot of changes for a 2.5 year time period. I’ve been just trying to get the ambient color right. The first combo I just wasn’t crazy about the ambient color of it. To be totally honest I’m not really trying to troubleshoot a problem Just sharing my observation on various bulb combos. Every tank is different. Too many factors

 

[jda]

This is still not the same. Bulb swappers can get some browning or some lightening, but death and tissue recession is not very common. I am not saying that this is good, but the issues are muted a bit with bulbs.

 

[mcarroll]

More recently I decreased the length of full intensity but otherwise it was always 10 hours. I know it’s a lot of changes for a 2.5 year time period. I’ve been just trying to get the ambient color right. The first combo I just wasn’t crazy about the ambient color of it. To be totally honest I’m not really trying to troubleshoot a problem Just sharing my observation on various bulb combos. Every tank is different. Too many factors

Understood. You just need to pick your favorite color and settle!

Do you have a cool LFS that at makes picking bulbs easy? (ie. returns, etc)

 

[xiaoxiy]

Understood. You just need to pick your favorite color and settle!

Easier said than done.

After 2 days of the GE6500s, I couldn't take the yellow anymore. Sorry guys, I caved.

I'm back to my good ol combo of C+ and B+, which has faithfully served me well for the past 6 months.