How fast can I lower my light intensity - LEDs

[paulsz]

Hi guys,

 

I know that raising your light intensity too quickly can burn and bleach corals. But how fast can I lower the intensity it without throwing their "comfort" off? My AI prime is currently running at UV/V around 70%, Blues at 90% and Cool White at 25% at it's peak. I wanna bring that down to around 55% for UV/V, 75% for Blues and 15% for CW. can I adjust it twice a week a few percent each time, over the course of maybe 3 or 4 weeks? Can i do it all in a week? All i worry for is the monti cap that is starting to lose some colour. I've also decided to change routes with the future of the tank. I wanted to go mixed reef but I think it'd be easier if i did just the monti up top with some LPS and softies elsewhere. Hence the reason i want to lower the intensity.

 

Thanks

[jservedio]

You can adjust it all at once downward - there is no harm in suddenly having less light. Monti caps can live in basically any lighting conditions - you'll just have deeper, darker colors in lower light. Before moving your monti up top, consider how fast they grow and the fact that they will shade everything underneath it - you can easily go from a 1-2" cap frag to a 12" across colony in a year or two if conditions are right.

 

Do you have any LPS under your light right now? As long as you start them off in lower light, most are pretty tolerant of high lighting levels so long as you have plenty of nutrients.

[paulsz]

20 minutes ago, jservedio said:

Do you have any LPS under your light right now?

I have one hammer coral i got about 3 months ago. Started as one small head and now is still one head, just much larger. It's sitting in about 130 PAR. Started off in about 80 PAR when i first got it.

 

But I did notice that some of my softies tend to not open up fully during peak hours. They are well extended up until peak time, then they retract a little.

 

22 minutes ago, jservedio said:

 you can easily go from a 1-2" cap frag to a 12"

I currently have it so that if it grows, it'll shade a bunch of mushrooms. Which i don't mind.

 

Thanks for the reply! I'll lower at once then. 

[jservedio]

34 minutes ago, paulsz said:

I have one hammer coral i got about 3 months ago. Started as one small head and now is still one head, just much larger. It's sitting in about 130 PAR. Started off in about 80 PAR when i first got it.

 

But I did notice that some of my softies tend to not open up fully during peak hours. They are well extended up until peak time, then they retract a little.

 

I currently have it so that if it grows, it'll shade a bunch of mushrooms. Which i don't mind.

 

Thanks for the reply! I'll lower at once then. 

If your LPS are only at 130 PAR, you should not lower your lights - that's not a lot of PAR at all.

[paulsz]

12 minutes ago, jservedio said:

If your LPS are only at 130 PAR, you should not lower your lights - that's not a lot of PAR at all.

That's at the bottom.  Once i get on the rock it's in the 150-300 range for the most part.

[jservedio]

13 minutes ago, paulsz said:

That's at the bottom.  Once i get on the rock it's in the 150-300 range for the most part.

Yeah, that's pretty much what you want if you have a mixed tank. How deep is the tank? You should be shooting for like 75-125 PAR on the sandbed depending on depth and even higher if it's a shallow tank for a mixed reef. For an LPS only tank, you can aim much lower, but with a mixed reef there are compromises if you want good color on the SPS - the shallower the tank is, the bigger the compromises.

 

Getting good color from both LPS and SPS in the same tank either requires a deep tank with a good PAR gradient or really carefully balancing your nutrients/dissolved organics and light levels.

[paulsz]

11 minutes ago, jservedio said:

 

Getting good color from both LPS and SPS in the same tank either requires a deep tank with a good PAR gradient

i think that could be my issue. I have the fluval evo 13.5, so it's only like 11.5 inches of water. The monti was doing pretty well for  acouple of months. Started growing after a couple of months of non-growth when i first got it. I had upped the flow a bit but everything else was just blowing around (the lps and softies). Then i tried lowering the flow a bit and it seems to have bothered the monti (not sure why though). Nothing else had changed, parameters were the same and the monti started fading and losing some tissue here and there. 

 

[jservedio]

30 minutes ago, paulsz said:

i think that could be my issue. I have the fluval evo 13.5, so it's only like 11.5 inches of water. The monti was doing pretty well for  acouple of months. Started growing after a couple of months of non-growth when i first got it. I had upped the flow a bit but everything else was just blowing around (the lps and softies). Then i tried lowering the flow a bit and it seems to have bothered the monti (not sure why though). Nothing else had changed, parameters were the same and the monti started fading and losing some tissue here and there. 

 

So with a shallow tank, you've still got a ton of options and there are two main strategies for your lighting in a shallow mixed reef.

 

1. High Gradient (more traditional way): you keep your light close to the surface while still maintaining full coverage to maximize PAR gradient. You have to choose your lighting pretty carefully for this. Since light intensity decreases by the square of distance, you will have a lot of PAR really high up and little down bottom. You keep your LPS on the sandbed and very bottom of your tank and your SPS up top. You can keep the widest array of corals with less acclimatization, but you are very limited in placement and placement is critical. A PAR map is really helpful to create for a tank like this.

 

2. Low Gradient: you keep your light far above the surface of the water with higher intensity so that the gradient between the surface of your tank and the sandbed is pretty minimal. From here, you chose LPS that can acclimate to higher light and SPS that are happy in lower light. With this setup, placement doesn't matter very much and can place things wherever you want within reason with good results. The big limitation is that you may not be able to keep all corals and things take really long to adjust. The biggest "pro" is that it allows you to mix your SPS, LPS, and Softies all together like this with great color, which is fantastic:

 

 

 

I've run tanks both ways and it all comes down to what you want to keep and how you want to scape your tank. With my current tank, I've got 14.5" of depth and opted for the 2nd strategy since it's worked really well for me. I can keep SPS down in the sandbed and all of my LPS as high as about 2/3 of the way up the rockwork before having lighting issues with my nutrient levels. That said, the more traditional way is easier to dial in.

[paulsz]

16 minutes ago, jservedio said:

I've run tanks both ways and it all comes down to what you want to keep and how you want to scape your tank

nice tank! that looks wild!

 

I've taken PAR readings when i first set up in the tank in the spring/summer. I took them over a few intensities. I'll go over it and see what course i may take.

 

Thanks for the help! super helpful!

 

[mcarroll]

On 1/18/2021 at 10:25 AM, paulsz said:

I know that raising your light intensity too quickly can burn and bleach corals. But how fast can I lower the intensity it without throwing their "comfort" off?

It's not about speed, it's about "too much change" which is subjective to the coral and environment in question.

 

So you can theoretically go up or down in light intensity with no problems....but only to a degree.  

 

So likewise, in either direction (more or less intensity) you can exceed the coral's current adaptations and cause problems.  (Folks have studied this....check Google Scholar.)

 

Under aquarium conditions, problems with dropping intensity levels are generally less likely than problems with increasing intensity levels.

 

Corals with access to plentiful amounts of dissolved phosphates (including excellent flow in the tank to deliver the nutrients) will tolerate a lot more change with a lot less damage.

 

Corals under phosphate stress (ie a lack of available phosphates) will be VERY sensitive and damage can be very acute...to the point of mortality.

 

On 1/18/2021 at 10:25 AM, paulsz said:

All i worry for is the monti cap that is starting to lose some colour.

If this is the reason for worry over your lights, then I'd look at other potential causes before you go messing with light settings.

 

How have your alk and nutrient levels been lately?

 

On 1/18/2021 at 10:25 AM, paulsz said:

I wanted to go mixed reef but I think it'd be easier if i did just the monti up top with some LPS and softies elsewhere. Hence the reason i want to lower the intensity.

Unless you're running a really extreme lighting setup (e.g. really bright or really dim) you should be able to host more or less whatever corals you want.

 

The numbers you've posted don't sound extreme, so IMO don't worry about your lights.  (If I was going to change anything it'd be turning down the V channel...maybe all the way to off.)

 

 

[paulsz]

7 hours ago, mcarroll said:

How have your alk and nutrient levels been lately?

Alk has been between 9.4 and 9.7 for the last month or so. 

Nitrates are between 10 and 25 on the salifert kit. Phosphates were at 0.2 and spiked up to 0.4 in the last two weeks. 

[mcarroll]

3 hours ago, paulsz said:

Alk has been between 9.4 and 9.7 for the last month or so. 

Nitrates are between 10 and 25 on the salifert kit. Phosphates were at 0.2 and spiked up to 0.4 in the last two weeks. 

As long as alk is stable at that level, those numbers should be excellent.  (I know 0.4 sounds high compared to what you may read, but it's not.)

 

Is it a coincidence that both numbers appear to be on the increase?

 

IMO lower (or eliminate) the V channel on your lights and see what happens – that's the only thing that seems "off" to me out of what you've described for us so far.   (Have your light settings changed at all?)

[paulsz]

26 minutes ago, mcarroll said:

(Have your light settings changed at all?)

I had raised them slightly (2% per channel for uv, v and blues) about a month or a month and a half ago. 

[mcarroll]

23 minutes ago, paulsz said:

I had raised them slightly (2% per channel for uv, v and blues) about a month or a month and a half ago. 

I would undo that change....as well as considering what I suggested about turning the V channels down further, maybe even all the way down to off.

 

I suspect that your Monti will stop fading.

 

Those "vanity colors" as I call them are there IMO for picture time, not for daily use – folks use them for faking all those hyper-real tank/coral photos you see around.  Very eye-catching even if they lack in realism.  🤷‍♂️

• Just picking the first example image from a google image search for "reef tank coral"....
  • The first example I saw that clearly used vanity emitters (possibly other techniques too):
    
  • First example I saw that DOESN'T (obviously) use vanity emitters:
    
    The most obvious difference is that reds and greens in particular don't have that fake-looking hyper-real look.

Vanity emitters are green, red, violet, etc.  They won't hurt anything (other than the perceptions of newbies 😉) during a short photo session.  

 

Generally speaking, blue emitters grow corals and "white" emitters let us see them better.  The rest are for show and should be used very minimally (ie tastefully) if at all during daily use.  Again all IMO.

 

At minimum undo that set of changes you made 4+ weeks ago – that's about the time frame it takes for damage to manifest if it's not very acute.  It might take just as long for the effects to reverse, possibly longer.

[paulsz]

30 minutes ago, mcarroll said:

V channels down further, maybe even all the way down to off.

would i do this all of a sudden? or over a period of a couple of weeks?

[mcarroll]

Since it appears to be a problem, I'd do it all at once.  When it's possible, you want to eliminate the apparent cause of damage to prevent things from getting worse.  (This isn't a regular lighting change.)

 

If you wanted a half-step, then first just roll back to your old light settings.  Then a week or two later, cut out the V channels.  (Or not if you decide not to.  You can decide in the moment depending on how the tank and corals are doing.)