Reef Lighting - Does anyone understand it?

[RC Slocum Rules]

So, if I use MH and T5 which should be the grower and which the color?

If I use the model of 10000K as the grower and actinic or blue bulbs as color would I want the growing power coming from the MH or T5?


MH = 10000K
T5 = actinic and other

or

MH = 20000K
T5 = 10000K and other


Make sense? This is not a color question. Don't come back with the classic lighting answer of
"it depends on what you want your color to look like".

 

[CubeNoob]

Makes perfect sense and I have thought of that exact situation myself. But I chose to go with my gut feeling and stay on the "blue" path so I went 20k or 14k + T5 Actinics. At first I went 10k MH + T5 Actinics and it does look really nice to the eye, coral colors are definately washed out under the light, but overall look is very pleasing. I just never got much growth... I did get some, and it was good and steady while the bulb held its spectrum. First time I did XM10k I went 6 months with it. First 2 months things seemed to do good, month 2-3 things slowed down, month 3 T5s all went out from overdriving them and were replaced. Little boost in growth month 3, but month 4-6 no real growth. At month 6 I replaced both my T5s and MH, tried a Radium this time to replace a 6 month old XM10k that was VERY yellow. Didn't work out well so I quickly put in a new XM10k until I figured out what went wrong. So I was back to original, and again, months 6-7 had pretty good growth but month 8 was a slowdown. At month 9 when it was time to replace the Actinics again I said "enough is enough" and that was the start of me really trying to figure this puzzle out. I think I am finally starting to figure out some of the reasons things were happening like they were, and it wasn't PAR related, it was Spectrum related.

So, to answer your question on which bulb combo I would pick for Grower/color, well, it depends how many T5s you have to work with, but I would go with something like a 14k or 20k bulb for the MH for sure, I will never use or recommend a 10k bulb again for a reef tank even though I do think visually it can look nice. For pure health aspects I can't recommend it when other bulbs seem to be much "healthier" for corals. For T5s, again, placement and # matter, but I would play with the bulbs to get the mix you want. I wouldn't put a daylight bulb in the T5, but maybe mix it up, 420, 454, 460, 75:25, 50:50.. lots of bulb combinations to tweak the looks of the tank just right with the T5s and use the MH as the workhorse/grower.

 

[shaggy14]

i recently did a test on the PAR measurements in my 2 tanks. i had 3 different 250w reflectors on the 90g long, 21 tall tank in this order, from left to right:
pfo hqi, pfo mogul, lumenmax 3
bulbs are:
phoenix 14k hqi(brand new), phoenix 14k mogul, phoenix 14k hqi(1-2 months old)
ballasts are:
lumatek, unknown hqi, lumatek

my par measurements with the reflectors 6 inches off the surface and the meter about 5 inches under the surface were around:
350, 300, 540
on the sand bed they were:
180, 250, 500

with just my 2x72in vhos(160w each) i got PAR readings in the 50-80 range

swapped out the pfo hqi reflector to a lumenmax elite, raised it 4-5 inches higher off the surface and with the meter at the same depth my readings were around:
730, 375, 535
sand bed readings went to
460, 280, 490

the middle number is lower because that is what is underneath my center brace, which is about a 12 inch long piece of glass

so in my tests, the actinic bulbs did almost nothing as far as their par-wattage-spectrum ratio

under my 6 bulb, 24in t5 NO lights on my zoa tank with 3x 10k and 3x actinic, par readings were around 200 under the surface and around 140 on the bottom

 

[barnett8]

<a href=showthread.php?s=&postid=15560711#post15560711 target=_blank>Originally posted</a> by CubeNoob

1: nm=nanometer is a unit of measurement. Here is a good read to understand it better. http://en.wikipedia.org/wiki/Light
Color............... Wavelength (nm)
Red ................ 780 - 622
Orange ........... 622 - 597
Yellow ............. 597 - 577
Green ............. 577 - 492
Blue ................ 492 - 455
Violet .............. 455 - 390

I feel really stoopid right now :hmm3: (I was thinking lumens.) Thanks for answering my other questions.

 

[greenbean36191]

Would the depth of the coral collected not also effect it's growth based on light temp?

In newly imported corals, yes. Corals and zoox both adapt to changes in spectrum and intensity of light to maximize growth though, which is part of the reason PUR is a difficult measure to use. Corals change the amount and location of various pigments and FPs depending on the amount and type of light hitting them. Zoox will shift position, density, and the concentration of photosynthetic pigments to adapt to spectrum and intensity as well.

This response makes it important to allow for a long acclimation period between growth trials though or you start introducing artifacts once you change the spectrum or intensity suddenly.

 

[teewhy]

If you guys will allow me to answer from a lamp perspective only (once the light hits the water - it's your responsibility )

First I want to say that I have also been impressed with the quality of thought that's been put into this thread. I happen to work in the lamp industry and I often tell people that nowhere will you find a more educated lamp consumer than in the aquarium market.

Now a couple of issues I'd like to comment on.

1. Color.

We measure our CCT (correlated color temp) in Kelvin. When a lamp is called out at 10,000K - it's assumed that a piece of metal that's heated to 10,000 kelvins will glow (or give off light) at approximately this color.

How this plays into this application has a lot to do with opinion and a little to do with Physics. Take a look at this graphic:

http://en.wikipedia.org/wiki/File:PlanckianLocus.png

The Tc(K) curve approximates color temp. As you can see, it's an exponential increase from 10,000K to infinityK. Typically it's very difficult (and rarely 'necessary') to measure color temp over 10,000K. Lamp manufacturers historically called anything over 6500K just a "blue" lamp. But reefkeeping has led to new marketing uses for higher K ratings. Most of these are not officially specified by the lamp manufacturer. Most Kelvin ratings over 10,000K are nothing more than "approximations" used to sell lamps.

On top of this, there are infinite combinations of halide combinations that can be used to create any single color. So each lamp company has their own "secret sauce" that they use to come up with any given color. It's the main reason that even 10,000K (easily measured CT) lamps from different companies have different colors and different PAR readings.

There is no "perfect" color combination that can be achieved. That's because color is a preference. It's what's great about having so many choices.

2. PAR

I leave it to you guys to debate the usefullness of the PAR measurements. But from the lamp standpoint - it's easy to see how the lower the CT, the higher the PAR. If it were only about PAR, everyone would use the 6500K lamps since those have the highest PAR readings.

The reason for that is that typically lamp manufacturers use Hg in their lamps to achieve the blue color. Hg gives off a lot of energy in the 365nM region which is outside of the PAR range. So it stands to reason that "bluer" lamps have a higher percentage of Hg in their fill, but less PAR since a lot of their energy is outside of the PAR specrtum (400-700nM)


I think I'll leave it at that for now. It's such a fun debate to watch because you have more choices in lighting today that you've ever had. Variety truly is the spice of life!

On a personal note - keep it up. It's this type of intelligent demand that challenges lamp companies to continually improve the product available to any given market segment. And as that happens, everybody wins.

 

[KarlBob]

<a href=showthread.php?s=&postid=15570677#post15570677 target=_blank>Originally posted</a> by teewhy
But reefkeeping has led to new marketing uses for higher K ratings... Most Kelvin ratings over 10,000K are nothing more than "approximations" used to sell lamps.

On top of this, there are infinite combinations of halide combinations that can be used to create any single color. So each lamp company has their own "secret sauce" that they use to come up with any given color. It's the main reason that even 10,000K (easily measured CT) lamps from different companies have different colors and different PAR readings.

Thanks for the professional insight, teewhy. The "approximation" and "secret sauce" factors go a long way toward explaining why an aging 20K lamp won't necessarily mimic a 14K lamp. Even if the spectrum has shifted, there's still the fact that the lamp ingredients may be different. A 20K bulb made with, for example, 15% sodium chloride, 80% potassium chloride, and 5% potassium iodide will probably never replicate a 14K bulb containing, say, 5% sodium chloride, 75% potassium chloride, 10% potassium iodide, plus 10% lanthanum bromide.
(Note: I made up the halide percentages above, purely to illustrate the point. They're almost guaranteed to be totally wrong. I'm sure the real blends are jealously guarded trade secrets, with way more than four ingredients)

 

[flomojo]

Very interesting posts here.

Seems like there's too many variables that severely affect a halide bulb's spectral quality and longevity, making halide bulb technology almost appear crude.

I am in the group of thinking that the bluer spectrums are more effective for coral growth, supported by some recent studies.

IMO, the next revolution in reef lighting is not necessarily the light source itself, but perhaps a medium in between an intense light source(s) and the illuminated subject which can actively manipulate the spectral signature to whatever is desired. With that, spectral shift of a bulb, or whatever light source, may be corrected (to an extent). Perhaps the medium doesn't need create the combination of bandwidths all at once? There could be multiple light sources, each with it's own active medium, and in combination, achieve the desired spectral signature.

Not sure what the medium would be, but perhaps lighting manufacturers might want to look into such technology. For the record, CubeNoob and I have had discussions about the possibilities of such actively controlled mediums.

 

[crazzyreefer]

Filtering Out

Filtering Out

In the early 80s I did some research for Phillips bulbs, 03, 05 and 07s attinics.

i have found that besides the way we currently handle our lighting, there is many more options, 3m company, has proven with older technology that you are able to use sodium bulbs, no loss of spectrum over time, but its only a 65k bulb, so just like a pair of sun glasses you can filter out the peaks higher or lower wave, with lenses to achieve the correct color temp. of course this may mean higher watts (unsure) to get the same desired results from MH but not necessarily sodium.

But in sodium there is a gentle sine wave without sharp jagged peaks, its light is the same as the sun, and its a possibility to add additional gasses to bring its focus into the ultraviolet spectrum only. it is still a few years away, but the output looks first hand at 4-10X the power of a same MH bulb.

Third problem with the use of bulbs that are available today, the bulbs give off uneven spectrum, you will see that the lighting color are not a gradual climb in spectrum, but a jagged mishmash of highs and lows. even with a 20k bulb, you don't have the complete ultraviolet spectrum, but just parts of it, another bulb will have other parts, but missing much more of the desired spectrum, so a shift in spectrum doesn't have to be completely across the lighting range but only one of the peaks, The one the coral was accustomed to use for growth. This add difficulty because par hasn't change a great deal, but pur has, and it may only be in the narrowest section of the spectrum to make a bulb completely useless. It would be as if we only could see one specific color and only the narrowest range of this color say less than 10 degrees, once the color shift, we would be in the dark. Corals in the wild receive the full spectrum corals on our tank have to be acclimated to this narrow color spectrum, and its changes makes the coral once again in the dark.

 

[KarlBob]

<a href=showthread.php?s=&postid=15577868#post15577868 target=_blank>Originally posted</a> by flomojo
Seems like there's too many variables that severely affect a halide bulb's spectral quality and longevity, making halide bulb technology almost appear crude.

It's not just halide lighting. Fluorescent tubes also have spectral quality and longevity issues.

Re: "Approximations used to sell lamps", it sounds like the Engineers and the Marketing Departments aren't seeing eye to eye, again. The Engineers don't know exactly what temperature it would take to make a black body put out a particular spectrum, but it would be over 10,000 k. The Marketing Department says "Ok, how about 14,000 k. It's more than 10,000."

The most recent example I can think of where departments got out of alignment like this is Microsoft, with Bing. The commercials promised "not a search engine, the world's first ever decision engine". When I hit the page to check it out after seeing one of those commercials, I found no mention of the words "decision engine" on the page. It was a pretty ordinary search engine, dressed up with some fancy tricks in the background photos.
Ok, digression over.

The active spectral control media idea sounds interesting, but I haven't the foggiest clue what kind of technology would do that. It almost sounds like force fields and gravity lenses to me.

A sodium bulb sounds like another neat option, but the mention of "a gentle sine wave without sharp jagged peaks, ... the same as the sun," got me thinking. For those of us in sunny places like Arizona, solar tubes just keep sounding like a great option. There's nothing closer to sunlight than sunlight, after all. I'm thinking that once I buy a house, I may have to chop some holes in the roof...

 

[flomojo]

<a href=showthread.php?s=&postid=15581111#post15581111 target=_blank>Originally posted</a> by KarlBob

The active spectral control media idea sounds interesting, but I haven't the foggiest clue what kind of technology would do that. It almost sounds like force fields and gravity lenses to me.

Keep in mind this is just me brainstorming, so I can't back this concept up with technical or scientific expertise.
Reefers who have outdoor coral farms under natural sunlight use simple transparent blue film to achieve desired spectra for coral growth/pigmentation. The medium I'm conceptualizing would be an electronically controlled filter/focuser, measuring the spectral cast emitted by the source and filtering/focusing it to optimal levels for coral growth/pigmentation/aesthetics. Maybe the medium would be LCD, nano-fiber, photochromatic technology, etc...who knows? But, even as the originating light source experiences spectral shift the medium would filter/focus it accordingly. I realize the light source(s) must possess the spectra in the first place in order for it to pass/focus through, but it wouldn't have to be as focused/narrow/limited to achieve the optimal spectral signature desired for aquaria. Perhaps the medium would allow for the use of more economical/longer lasting industrial lamps not suited for aquaria use. Or, the medium could allow for multiple types of previously unsuited lamps to achieve the spectral cast optimal for aquaria. Again, just brainstorming here.

 

[GUILLO1]

Hey anyone know what happened to CubeNoob and Flomojo?? This is one of the most interesting threads I've read here on RC in a long time and now they have been Moved On.

 

[KarlBob]

<a href=showthread.php?s=&postid=15585035#post15585035 target=_blank>Originally posted</a> by GUILLO1
Hey anyone know what happened to CubeNoob and Flomojo?? This is one of the most interesting threads I've read here on RC in a long time and now they have been Moved On.

I have no clue what happened to them. I didn't even notice they had Moved On.

 

[Hookup]

In an effort to keep the topic going. I wanted to share my view on photosynthesis within zoox and how it applies to lighting our tanks. I offer this for scrutiney and correction and certainly not as fact, other than it is a fact that I think this is how it works...


1) photosynthesis consumes a photon to produce energy for the coral any photo will do.

2) some photons are more effectively used during the photosyntehsis process than others. A 400nm photon will produce more photosynthetic "sugars" than a 700nm photon will.

3) there is a limited amount of photosynthetic reactions that can occur before saturation is achieved within a coral. Night time resets everything.

4) over-satruation is "harmful" to a coral, it has to recover from it where it could be using that same energy to grow.

5) waves traveling thru water are dispersed. Red (700nm) is more easily dispersed than blue (400nm) hence why par readings are higher under water for blue bulbs than red.


If the above is in fact correct, then we can divide the "problem" into two distinct parts. Growth and Coloration.

Growth - to achieve maximum growth, we want to be dumping enough photons onto our coral subject where we achieve saturation without exceeding it. Any photon will do.

Coloration - to achieve maxium coloration we want to have a healthy coral subject (see growth, plus many other factors) and ensure that the spectrum we are baking our corals in provides the "best" amount of color/reflection. (sorry, i'm weak on what actuall makes a coral give off the color it does).


I currently have an XM20k bulb with 4 22" T5 10k for supplements. It's been 2 weeks. Things are continuing to look better than ever. I also keep my lighting scheudle to 8/10 hours (MH/T5) so I do not achieve over-saturation on the corals.

I chose that combo because I theorized that 20kXM would give me the "best quality photon's for photosyntheisis" where as the supplemental T5's would give me the missing spectrum for color.

I realize that this is very backwards to normal setups for lighting, and admittedly a big part of the "why" do it this way was because it was what I had as an MH bulb... but I did drop all my 460nm T5's and swap, on purpose to 10k bulbs to test this theory. Lets say my LFS just rolled his eyes and sold me the bulbs anyhow..

 

[crazzyreefer]

Yes but..... We do not know everything... so the answer is difficult because we don't understand the question....

It could be as simple as placing a coral under a 20k bulb and it grows... but we know this isnt the truth, Corals adapt to our lights, and then have to readily adapt again every time the light shifts, so dose it make a difference? I dont have that answer. But the slow down on growth as the light shifts color, is an indication that they are not processing the new peak shift as well as we previously believed. As far as solar tubes, through a filter is the best way, but if you use a standard MH bulb and add a filter, the shift in will be the same, it will not be at the same peaks and lows. there for the corals will have to re-adjust to the new lighting.

Marketing and production.... a 1gig computer chip is tested and if it clocks out at 1.6 it goes in the 1.6 bin... the bulbs are not even tested, other than if it lights up... so it could vary from bulb to bulb. The R&D made sun tanning bulbs, their question was could it be used for another purpose? The marketing department job is to reassure them that it can be sold in everything from dental cleaners to reef tanks..

 

[greenbean36191]

2) some photons are more effectively used during the photosyntehsis process than others. A 400nm photon will produce more photosynthetic "sugars" than a 700nm photon will.

Some photons are captured more effectively, depending on their wavelength, but after that all photons that are absorbed by the zoox are equal in their ability to perform photosynthesis. You get the same amount of sugar from a 400 nm photon as you do from a 700 nm photon. All the matters is that the photon has enough energy to kick off the reaction (equivalent to a red photon). Any excess energy is lost as heat or fluorescence.

3) there is a limited amount of photosynthetic reactions that can occur before saturation is achieved within a coral. Night time resets everything.

Saturation has nothing to do with how long the light is on. It's simply a matter of intensity. It occurs when photons are hitting the zoox faster than they can shuttle them through the reactions of photosynthesis. Photosynthesis doesn't become less efficient as the day goes on (unless the intensity is so high that it's causing damage). Saturating light intensities will be saturating as soon as the light is turned on and will continue to be just as useful to the coral for as long as the light is on. Sub-saturating light intensity will not saturate photosynthesis regardless of how long the light is on.

4) over-satruation is "harmful" to a coral, it has to recover from it where it could be using that same energy to grow.

Yep, too much light (intensity, not duration) damages the photosynthetic machinery. At intensities that exceed saturation the damage accumulates for as long as the light is too bright. It's a double whammy to the coral too since they can't produce as much energy because of the broken machinery AND they have to spend more energy to fix it.

 

[Hookup]

Thanks for the clarifications, however it now presents a few new problems or questions anyhow.

Given saturation is an intensity level, not a duration, could it be expressed in terms of PAR?

Is there any data that suggests what corals, if any, have what saturation levels? I'm guessing no, otherwise it would be widely published.

Would the "saturation-effect" be part of the factors that have some corals do much better in "high light" and others in "low light"? i'm guessing unscientifically yes, this is the general factor between "high light requirement corals and low light requirement corals".

I think, if I understand the above, that a given intensity of 700nm photons will not saturate a coral as well as the same intensity of 400nm photons... but stated back in this thread, a typical bulb will produce more 700nm photons relative to the quantity of 400nm photons... which, assuming that is correct, leads me to ask:

Does that ratio approximate the photosynthesis effectiveness ratio between 700nm and 400nm photons?

BTW: I am completely generalizing 700 vs 400... maybe I should say red vs blue, but I find that is too vague based upon my current level of "limited" understanding.

Now looking at color of a coral:
For any photon that can kick-off the process, wouldn't a photon that has an excess of energy produce the most color due to the byproduct of fluorescence?

Color is the reflection of light, a specific wave length(s) of light, therefore if we are not supplying that wave-length via the bulbs would the colors not be muted by comparison?

Thanks for indulging. I feel like an ape trying to learn sign-language from some advanced species when I ask these questions to you guys/gals.

 

[greenbean36191]

Given saturation is an intensity level, not a duration, could it be expressed in terms of PAR?

Is there any data that suggests what corals, if any, have what saturation levels? I'm guessing no, otherwise it would be widely published.

Yes, it can be expressed in PAR. No, there is no data on what levels are saturating for which corals because saturation is specific to each coral and varies over time (and even within different parts of the same coral).

Would the "saturation-effect" be part of the factors that have some corals do much better in "high light" and others in "low light"? i'm guessing unscientifically yes, this is the general factor between "high light requirement corals and low light requirement corals".

A bit, but it's also largely based on how much specific corals seem to rely on autotrophy vs. heterotrophy.

I think, if I understand the above, that a given intensity of 700nm photons will not saturate a coral as well as the same intensity of 400nm photons... but stated back in this thread, a typical bulb will produce more 700nm photons relative to the quantity of 400nm photons... which, assuming that is correct, leads me to ask:

Does that ratio approximate the photosynthesis effectiveness ratio between 700nm and 400nm photons?

Again, it depends on the zooxanthellae, and on the bulb. The actual peaks in absorption for zoox are around 440 and 660 nm and at those peaks the ratio of absorption is about 6:5. Bulbs can be all over the board.

Also, keep in mind that we're still ignoring the effects of attenuation by the water and absorbance/ reflectance by the coral itself.

For any photon that can kick-off the process, wouldn't a photon that has an excess of energy produce the most color due to the byproduct of fluorescence?

Not necessarily. The colors and fluorescence you see are due almost entirely to the coral itself and have no direct relation to photosynthesis. The fluorescence from photosynthesis is mostly red (same in green plants) and without special equipment you won't see it.

Now the fluorescent proteins produced by the coral itself tend to be excited by bluer light, but if a given protein isn't being expressed or wavelengths that fall outside of its excitation spectrum are used then no fluorescence regardless of whether the light is red or blue.

Color is the reflection of light, a specific wave length(s) of light, therefore if we are not supplying that wave-length via the bulbs would the colors not be muted by comparison?

Well the colors in corals come from non-fluorescing pigments and from fluorescent proteins. If there is no output of red light from the bulb for instance, then yes, the red or pink non-fluorescing pigments will be muted because there is no red light to reflect. BUT, fluorescent proteins don't work that way. Fluorescence works by taking light at one wavelength and then re-emitting light at a lower wavelength, so the color you see doesn't have to be present in the original light source.

In the wild, if you go down 120 feet on the reef everything has a blue cast to it and there's not much color since almost all of the red light is already gone. There is only one color that stands out against the blue though- the bright red mushrooms. Even with virtually no red light at that depth the corals are as bright red as they are near the surface because of a fluorescent protein called DsRed which takes in blue light and emits red.

 

[Hookup]

First, thanks for answering and clarifying GreenBean36191. I've read other posts of yours around this subject, and obviouly miss interpreted them, but I am clear (er) now...

I feel like I have all of this new knowledge and yet cannot lend it to making a "this is the optimum scenario for lighting a generic reef tank" statement. Though I fully realize there will never be "one right way", if we had one framework that was proven to work, then we can create theories and scenarios that push that framework forward in a more controlled mannor. (I guy can dream can't he?)

I need to re-read what's been posted, and process it a bit further before I ask/comment further, just wanted to say thanks.

BTW; didn't mean to hijack the thread... thanks again to all for indulging... my questions/comments are leading up to some summation of how lighting actually works to create growth and coloration in the aquarium... I hope.

 

[Hookup]

After re-reading the entire thread, twice, here's what I've learned.

There are many factors that are attributed to effective coloration and growth of any given corals within our aquairums. However, when looking at the single factor of light & our corals and obtaining effective/maximum growth due to maximizing the photosyhtentic process we can conclude the following based solely upon the information offered in this thread (making this the true defintion of internet-pusedo-science);

1) Color Temp on bulbs can be missleading. Anything over 10k is not necessarily an accurate representation, however it generally equates to a blue(er) spectrum the higher the number. One poster reports the Phoenix 14k being the bluest of all, but as a rule the higher the CT, the bluer.

2) Corals like blue light in the 460nm range for photosynthesis better than most other wavelengths. If you're looking to maximize growth, focus your spectrum and maximize the intensity around this wavelength.

3) Photosyntehtic saturation is bad. But it seems we do not have enough information to understand what approximate levels of PAR equate to photosynthesis saturation with any coral. This leads me to believe that in an effort to maximize coral growth, we could/should dump as much light (intensity/high PAR) as we can onto our corals until we observe an adverse effect that is attibutable to the intensity of light on the specific coral(s) we are observing. Additionlly if we want to maximize growth, we might as well use "the good stuff" and provide light in and around the 460nm spectrum (blue lite = the good stuff) .

4) Bulb/Balast combinations can shift output spectrums more quickly than the typical 10-12month life-span that we attribute to bulbs as a rule, which inturn could adversely affect the corals in our tanks. PAR readings might not reflect this spectral shift, therefore we need a new tool, or an expensive spectrograph to know when our bulbs are no longer outputt'ng the "good light". This is terribly unfortunate, given the costs of those tools are prohibitive.

This leads me to conclude, if we want to maximize our coral growth, we should be driving "blue" MH bulbs as the main source, to deliver maxium intensity (PAR) to the corals throughout the tank, and even supplimenting that with additional light sources such as T5's that put out even more 460nm light (actinic lights).

This might not give the most pleasing look to our corals, but it would maximize growth, assuming that other factors for growth are at optimum levels. Not all corals thrive when the only source of energy they recieve is from photosynthesis. Similarly, it is assumed that general tank conditions are maintained in accordance to the currently accepted norms. Broad and bold statements for sure, but if we do not lock down some of the variables it will be difficult to move forward.


Thoughts?