Acorral's UAS test

[acorral]

This is my first prototype setup:

- 5" x 9" screen
- 5 x Deep Red 660 nm Osram Leds at 1000 mA
- Hagen Optima Airpump
- Traditional 5" blue airstone

This is on my sump on a 2 years old 400 gallon mixed reef running a Octopus XS 350 Skimmer and Biopellets running for 2 months but don't really kicking in nor helping with algae reduction on display tank

I don't really know what to expect since many say Biopellets outcompete algae scrubbers... for me that would mean on the first place that the algae on my DT must have already died and that is not true in my case

So I'm taking this as a first experiment with 3 objectives:

- Test the design factors for successfully making the bubbles rub the screen
- Test design factor to successfully illuminate a one sided mesh with red LEDs
- Test design factors on doing an easy to clean screen

If it happens that the UAS helps me with the algae on my DT outcompeteing my "not-working" biopellets, then that an extra for me !!!

After refining those design factors I have a friend with a 625 gallon reef tank that wants to give it a test in order to be able to go skimmerless and sumpless with a UAS, so I am planning on running this test for a few months and then install it on my friends tank, be sure I'll post that test here

[acorral]

Now the pictures:

http://img821.imageshack.us/img821/3033/uas2zm.jpg
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And a short video:

http://www.youtube.com/watch?v=f3r4NHunmaA

[acorral]

This test has one week running...

I seeded it with some GHA I extracted from my display tank by just rubbing it, probably useless but I did it anyway...

I can see now some dinos and very few green spots on the mesh, I checked it at 1 week and decided not to clean anything until seeing a little bit more growth

I know that 5 LED's maybe little less than specified for this 1 sided screen, I satrted with that because I had those leds laying around collecting dust so I put them there... I already ordered 5 more LEDs, this time CREE 630 nm LED's to have them mixed along with one Royal blue that I have around here so the final configuration will be 5 Deep Red + 5 Red + 1 Royal Blue at 700 mA

My photoperiod is now set at 18 hours, I just read that for LED's I can reduce that to 12 so I will later today

[SantaMonica]

I'd keep it at 18 hours.

[acorral]

Little update at one week and 3 days from installation...

Found brilliant green strings of algae attahed to the glass between the leds and the UAS, removed it and thoroughly scrapped the glass to encourage algae not growing there and growing on the mesh

I also noticed dinos all over the place, diatoms or brown algae and some green spots on the screen

I noticed that the area just in front of the leds are shoing a yellow tone, not brown nor green, I've heard about that meaning roots dying... could it be that the LED's are too close? not enough flow? not enough food? help here on the meaning of yellow zones please

Guess on saturday that the second week ends I'll have something more interesting to scrape from the screen and take some pictures

[SantaMonica]

Pics please.

[Floyd R Turbo]

Review my thread, you are describing precisely what I experienced on my scrubber in the first week. Almost exactly.

[whites]

Wasnt expecting you to jump into the tank... very cool!!

[acorral]

Review my thread, you are describing precisely what I experienced on my scrubber in the first week. Almost exactly.

Thank you Floyd I have read your thread many times I know you made many changes:

-placed the leds as far as you could
-changed the spray bar
-placed the diffusor on blue led
-I couldn't findinformation about you re-roughing your screen but I guess you mentioned it, right?

Regarding the LED's distance I have placed the 1 inch farther than they used to and expecting to see some results

Regarding the spray bar... have you seen the video? I guess they are rubbing the screen correctly, what do you think? i have around a round spray bar that I can use but I guess that if it not broken don't fix it, on my limited unexperienced knowledge seeing the underwater video of the screen and the bubbles I guess they are rubbing the screen, what do you think? this is room for improvement?

I haven't been able to find the light diffusors you got, from where you got them?

Did you re-roughed your screen?

What of the factors you stated you think are the important ones and seeing my video what's your opinion?

[acorral]

Pictures from yesterday...

This is the algae I collected from one spot in the glass:
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This is the screen at day 10, you can see the dinos, some green and a almost perfect round zone with very little yellow growth just in front of where the LED's are concentrated:
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[Floyd R Turbo]

WHOA - camera underwater! Not expected!!! LOL

Yeah I think your bubbles are great, lots more than I had. To me it looks like your screen has more green on it than mine had at that point (not counting the first week). That could be due to the higher amount of bubbles. I would just leave it be, whatever you're doing is working.

From my experience, I the screen was not growing anything right in front of the blue so I backed it off and put the diffuser over the blue until it filled in with green in the holes. I now run it 12/12 with the lights as close as I can get them and zero burning. I think initially I was dealing with photoinhibition of GHA so backing off and such was probably the right move. Also after it turned thick and green I was running 18/6 and got a dino coating by the 3rd or 4th day, then Garf told me he thought it was overillumination, and when I knocked it back they didn't really start to form until day 5 or 6 and wasn't nearly as much on day 7 compared to day 4 on 18/6.

The diffuser is just a section cut from a 2' x 4' sheet of diffusion grating. You can find these in most big box hardware stores that sell the recessed "troffer" light fixtures (that go up into a ceiling grid system). They will be in the same area as the white and reflective egg crate, and the 2' x 4' acoustic ceiling tiles. Anywhere that carries those items will have it. It's called a "prismatic diffuser".

I have not re-roughed my screen, I just left it alone. Initially I thought I might not have roughed it up enough after reading SM's UAS post, but decided just to leave it be.

As far as the dinos go, in the tank I run the waterfall scrubber on I also have several different areas where I use the plastic canvas to prevent salt creep from microbubbles popping, strainers, bubble blockers for effluent from the scrubber, etc. All of these grow copious amounts of dinos. My conclusion is that any kind of soft plastic (white egg crate included) will grow dinos if it is exposed to the water (i.e. not encrusted with coralline or covered in a thick mat of algae). So until your screen gets some thick green growth, you're going to grow lots of dinos, but it will pass.

[acorral]

Thanks for the comments...

I'm thinking on another version of a 2 sided screen using submerged mirrors, the problem is with the metalic stuff in mirrors... so Santamonica: The flexible reflector material you sell on your site, are they submersible? are they reef safe?

Another point to discuss... what bout puutting diffuser grating for the whole lamp, not only blue ones? to mix the light... any comments on this?

[Floyd R Turbo]

yes that would be fine. Diffusion grating knocks the light down a little, but with LEDs being as localized and intense as they are, is it probably an even trade off. Diffusing the whole array will give better overall coverage, and then you just put it closer to make up for the slight intensity loss.

[acorral]

yes that would be fine. Diffusion grating knocks the light down a little, but with LEDs being as localized and intense as they are, is it probably an even trade off. Diffusing the whole array will give better overall coverage, and then you just put it closer to make up for the slight intensity loss.

Sounds good... I'll give it a try... what abut the reflecting flexible sheets? do you know if those are safe?

[acorral]

Cleaned the screen today after 2 weeks of running...

Before cleaning:
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After cleaning very little algae:
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I'm happy that I'm seeing green on the screen but still not in the center of the light source...

Guessing what shoudl I do to fix that... many optionc crossing my minda, like:
- Increase feeding
- Turn off biopellet reactor
- Reduce photoperiod, currently running at 18/6
- Introducing a light diffuser
- Heard about adding Iron, which I consider not viable since it could fuel the algae on my Display Tank

Help from the experts here !!! what should I do to make it grow green in the center also?

[Garf]

Acorral - see if this prediction applies in your case;

http://algaescrubber.net/forums/showthread.php?1838-Co2-turbo&p=20253&viewfull=1#post20253

[acorral]

Short video before cleaning:


http://www.youtube.com/watch?v=T3J0gj5ZJQc

[acorral]

Thank you garf, you maybe right so why don't try...

I will be adding this week a royal blue led and putting a light diffuser grating infront of the leds

I'll post results here

[SantaMonica]

It is certainly burning the middle. There is already plenty of iron, since it grows green on the sides. If you can't spread the light out, then a diffuser might help. Lastly, less hours.

[Garf]

I am doing a waterfall bubble screen (tm) and I found that low lighting promoted green growth, then applying higher light accelerated growth when the screen was ready.

[acorral]

I am doing a waterfall bubble screen (tm) and I found that low lighting promoted green growth, then applying higher light accelerated growth when the screen was ready.

To low lighting you mean photoperiod? or light power?

[Garf]

To low lighting you mean photoperiod? or light power?

Light intensity.

[acorral]

I'm seeing negative effects on my tank, not caused by the UAS fro sure, most likely caused by the biopellets, one blue acropora bleaching from the base... I have heard about this kind of results with biopellets and now I'm seeing them first hand.

On the UAS factor... this week I'm not seeing the same algae growth as the last one, from what I can see with only 3 days of growth... I blame biopellets on this too

Do you think it would be safe to just unplug the biopellets to solve both issues? stop bleaching the acropora and leave nutrients for the UAS to mature faster...

Would the inmature UAS be capable of not letting my nutrient levels sky rocket? The biopellet reactor has running only 3 months

[SantaMonica]

Should not run pellets with a scrubber.

[acorral]

Should not run pellets with a scrubber.
Thank you santamonica, I know they are not meant to run together that's why I want to unplug the pellets, the question is regarding a word of advice on how to do the switch given the fact I am at week 3 of a new UAS that has not matured yet

[SantaMonica]

I would just remove them.

[acorral]

I would just remove them.

Done... just removed the biopellets from my system.

Another recent mods:
- Added a light diffuser
- Made a mirror array to convert it to 2 sided

On Sunday I'll receive the extra LED's I ordered so I will modify the lamp to have 11 leds, 10 red, 1 royal blue and have them positioned to be 2 sided as well as placing the mirror array inside the sump

So I'll be posting pics on monday for sure

[acorral]

Yesterday I cleaned up my UAS, well, just rinse it a little bit to get rid of some dinos and brown slime I didn't really scrub anything to let it spread a bit more:

2463

As you can see there's still a yellow patch at the center, guess taht's being caused by tooo much light on the area given that the lamp had 5 LED's concentrated on that small area...

I made the following changes to the UAS:

- Made an in-sump embodiement 90 degree reflector to make it 2 sided
- Modified the lamp to have 4 Deep Red Osram LED's + 4 Red CREE LED's + 2 Red-Orange CREE LED's + 2 Royal Blue CREE LED's, giving a total of 12 LED's, 6 for each side, all of them are running in single circuit running at 700mA
- Added a light diffuser for the whole lamp

Lights ON with diffuser in place:
24642465

Lights ON without diffuser:
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Top view:
2468

Lights off without diffuser:
246924702471

I'm placing the lamp 3 inches far from the tank and will be moving it closer slowly to avoid burning the algae with the increased light

Stay tuned for updates with the new setup

[acorral]

Regarding the results of unpluging the biopellet reactor... One day after shutting them down I saw a little cyano bloom on the sand that is slowly going away... My phosphate levels still are undetectable and nitrate level boosted from 0.1 to somewhere between 0.2 and 0.5

[acorral]

I'm getting very good results with the new reflector and leds, growing much more green and without the yellow center patch... Giving it a complete week to scrub and take more pics.

Phosphate still undetectable and nitrate beetween 0.5 and 0.2, acros stopped bleaching without the biopellets !!

[SantaMonica]

Love no pellets :)

[tebo]

great, now tell me about the reflector, take a picture to view And pass those pictures hehehehe


regards

[acorral]

great, now tell me about the reflector, take a picture to view And pass those pictures hehehehe


regards

On the weekend cleaning I'll take it out and take some pictures

As a midweek update... The whole screen is now growing green, hope to see some 3D growth soon

I've seen many stomatella snails surrounding the UAS... are they harmful to the algae or is it ok to let them roam around ?

[SantaMonica]

I think any snail is going to eat.

[Garf]

How on earth you gonna stop them munching on your screen? Perhaps suspending the rig so that they cannot physically get onto the screen, otherwise you may have built a snail factory !

[kerry]

My pleco in my FW 125G takes care of my screen.

[acorral]

Some pics of the screen at wk4... slimy but green !!!!

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Nitrate is zero on salifert test

Phosphate is ???? I don't know cause I got out of PO4 reactive drops #1 on my test kit... Getting a new test kit soon so I can post PO4 concentration but guessing it's zero or near zero too

Algae on display is getting weaker on some spots so I keep siphoning it out of the systme to help getting rid of it !!!

Happy with my UAS so far !!! and still tinkering around an idea to keep nassarius and stomatella snails away from the screen

[SWhite]

great, now tell me about the reflector...

This please^^

[acorral]

Here is the reflector I took it out for cleaning, the mirrors get dirty very often...

Everything is made from 6 mm white trovicel that I had collecting dust somewhere around and glass mirrors, I sealed the mirrors sides with silicone to prevent water getting in contact with the metallic part of it

The reflector goes facing the glass and the height is 1 inch less than the water level, notice the space between the base and the mirrors, they are there for letting the water in and reducing the light reflected on the stone

Haven't noticed any important algae growth on the stone, but in case of having it I can add a cover for it

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The bubbles itself make a very good upflow, sucking water from the slots on the bottom and letting it out at surface level

The screen is pressure fitted on the plastic base that holds the blue stone diffuser in place, that makes it easy to take out for cleaning

[acorral]

I just measured nitrate and phosphate, both mark undetectable with salifert test kits

I keep seeing green dust algae over the display tank front glass, some days a little and some days lots of it, I'm thinking on adding hours slowly, one by one, to the photoperiod from the 12 hours on I have now to 18... what do you think?

[SantaMonica]

Yes, because your screen is dark, it needs more hours/illumination.

[acorral]

Yes, because your screen is dark, it needs more hours/illumination.

Thank you SantaMonica, would it be too much shock going from 12/12 to 18/8 directly or better do it gradually? let's say... add 1 hour daily

[SantaMonica]

I don't think it can be shocked.

[acorral]

changed the photoperiod to 18/8 but with the diffuser and got good results... after some advice from Floyd R Turbo I decided to change the photoperiod to a shorter one with higher light intensity so I removed the diffuser and set a 9/15 schedule, got some yellow growth and reduced the on perdio to only 8 hours, and I'm getting good green growth...

Now my question is... I don't like the fact of having the UAS "making it's thing" only one third of the time... what about having it 8on/8off instead of having it 8on/16off?

[SantaMonica]

Stronger light, for less hours, is the most powerful photosynthesis you can have.

[acorral]

Stronger light, for less hours, is the most powerful photosynthesis you can have.

Thank you, and after 8 hours of light how many hours do I need to keep the light off? I want to reduce the off time having it oscillate on for 8 hours and off for the minimum time needed to give rest to the algae and not loose effectiveness...

[Floyd R Turbo]

Whether it's UAS or waterfall, splitting up the photoperiod shouldn't affect operability. Worst case is that it might help a bit. The reasoning behind splitting the photoperiod was to avoid photoinhibition. The problem is that photoinhibition actually happens very fast - depending on how you interpret the data, on a cellular level it can happen in a matter of milliseconds. I don't want to get way off topic here but a couple studies I read that discussed 'flashing' and the effect of photosynthesis showed that if you have the light "on" then "off" in a cyclic pattern (in the kHz range) that you got the same effect as if the light was on constantly. Also if you had the light "on" then the "off" period was longer (like 5-10x longer) that you also got the same or better results.

The point here though is that kind of by accident, we already do this. Think about a pool on a sunny day. Someone hops in and gets out. What do you see? All kinds of bright lines intersecting and chasing each other. You see the same thing in the ocean on a sunny day, or in your aquarium if you have point-source lighting (LED or HID). These lines are variations in intensity that are caused by the variations in the water surface, which has a lensing effect, focusing the light in some areas and de-focusing it in others. So with a waterfall type scrubber, you have a sheet of water passing over the screen that creates this effect. With a UAS, you have bubbles that create this effect.

The only caveat to this is that there is not much of a flashing effect with Fluorescent light sources, linear sources are too uniform. That is why you don't get the shimmer with those over your tank. I would imagine that this is part of the reason why LED scrubbers tend to produce less yellow/caramel algae, but that is just an educated guess. Yellow/caramel algae has thusfar been associated with too much light compared to the nutrients provided. It could also indicate long-term photoinhibition on a broad (screen-wide) scale. Not enough people running LEDs to tell if the yellow algae will continue to be a pest in systems that are over-scrubbed.

Wow, I guess I did get off topic.

[acorral]

Thank you Floyd, I'll experiment with that... I'll start on 8on/8off and then I will try to reduce it to less hours off gradually and see what results I get...

[acorral]

Changed it to 8on/8off and algae is growing faster and greener !!!

I'm still getting some brown growth over the green one, and the green is still slimy, not like strands of hard strong green algae... Is this something I need to fix or is it just matter of time and having lower nutrients?

[SantaMonica]

Probably time.

[acorral]

The UAS keeps working great, Phosphates and nitrates are still VEEEERY low !!!! The 8 hours ON and 8 OFF schedule is working great

The screen grows green attached to it and brown slime covering the green, I know that on ATS it should be only green, but I guess it's matter of time and still it's working great

I saw some pics of really rough screens and found out that my screen needs to be roughed up a little bit more...

I will be re-roughing the screen on these days and will be posting results here

[kotlec]

How did you managed to program your timer for 8-8 shedule? I have 8-16 now and feel like loosing some scrubbing capacity.

[acorral]

How did you managed to program your timer for 8-8 shedule? I have 8-16 now and feel like loosing some scrubbing capacity.

I have a Neptune Apex that has a "Oscillate" command, that way I can control it to oscillate ON/OFF with a certain amount of minutes for each phase... with a regular timer you would be very restricted to do this...

If you are on 8-8, perhaps your algae will respond OK if you switch to 6-6 twice a day, or 7-5-7-5

I will gradually start reducing the off time to try to make my UAS more efficient by minimizing the OFF time without loosing efficiency

[srusso]

Whether it's UAS or waterfall, splitting up the photoperiod shouldn't affect operability. Worst case is that it might help a bit. The reasoning behind splitting the photoperiod was to avoid photoinhibition. The problem is that photoinhibition actually happens very fast - depending on how you interpret the data, on a cellular level it can happen in a matter of milliseconds. I don't want to get way off topic here but a couple studies I read that discussed 'flashing' and the effect of photosynthesis showed that if you have the light "on" then "off" in a cyclic pattern (in the kHz range) that you got the same effect as if the light was on constantly. Also if you had the light "on" then the "off" period was longer (like 5-10x longer) that you also got the same or better results.

The point here though is that kind of by accident, we already do this. Think about a pool on a sunny day. Someone hops in and gets out. What do you see? All kinds of bright lines intersecting and chasing each other. You see the same thing in the ocean on a sunny day, or in your aquarium if you have point-source lighting (LED or HID). These lines are variations in intensity that are caused by the variations in the water surface, which has a lensing effect, focusing the light in some areas and de-focusing it in others. So with a waterfall type scrubber, you have a sheet of water passing over the screen that creates this effect. With a UAS, you have bubbles that create this effect.

The only caveat to this is that there is not much of a flashing effect with Fluorescent light sources, linear sources are too uniform. That is why you don't get the shimmer with those over your tank. I would imagine that this is part of the reason why LED scrubbers tend to produce less yellow/caramel algae, but that is just an educated guess. Yellow/caramel algae has thusfar been associated with too much light compared to the nutrients provided. It could also indicate long-term photoinhibition on a broad (screen-wide) scale. Not enough people running LEDs to tell if the yellow algae will continue to be a pest in systems that are over-scrubbed.

Wow, I guess I did get off topic.

The better part of this all is, when you dim LEDs you aren't using less power... To dim LEDs you have to "flash" them extremely fast. One might suggest that dimming scrubber LEDs may increase photosynthesis... based on the same findings... :)

[SantaMonica]

You never want to dim; only On or Off.

Dim light produces more dissolved organics, and less physical growth.

[Floyd R Turbo]

This is where things differ with LEDs. PWM dimming is basically turning the LEDs on and off more rapidly. Using dimmer fluorescent light in completely different. Intensity is lowered with fluorescent, while intensity with PWM dimming is not, it is just intermittent. There may actually be higher efficiency with the flashing effect of PWM dimming instead of analog dimming, maybe not from growth ratess but rather power usage not achieve those rates

[SantaMonica]

It would be up to the physiology of the algae then, as to how short the pwm time segments could be before the algae considered it just "dimmer" instead of on/off. Surely the electrolytes in the algal cells cannot move in and out of the cells as fast as electrons can move in or out of a p/n junction.

[kerry]

I have been on the fence with this as well. I have wondered if the algae could could take advantage of the on/off burst rate of the electronic switch rate. It would be handy to know how many seconds on to how many seconds (milliseconds or microseconds even) off the LED would have to be for the algae to do its thing. Maybe a long burst with just a few seconds off??? I have not dug real deep yet but I could not find any info on this yet.

[herring_fish]

I agree with what is started above. My skim reading of the articles that I could fine leads me to believe that flashing is very forgiving, although they point to frequencies that are the very fast. Algae does empty the bucket very quickly.
Early studies, used a spinning disks with a hole cut in it that was placed in front of a light. they started with less than a second and modern studies, with LEDs are in milliseconds. Most of the studies like much more off time than on. All that being said, it does not have to be optimal to get a big advantage.

One thing that could be done is to overdrive your LEDs. With proper knowledge of temperature dissipation rates, you could drive the same LED brighter and not have it burn out prematurely. This could give you better algae yields.

[daninfamous]

thanks for providing all this info, love this build, want to try something close to this once I get my new tank set up.

[acorral]

This is second cleaning after changing to 8on and 8 off

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Based on the color of the algae I'm thinking about moving to 9 on/ 7 off and see what I get... any opinion from the experts here will be appreciated !!!

[SantaMonica]

Looks great.

[acorral]

Looks great.

Thank you !!! what do you think about adding one ON hour and reducing one OFF hour ???

[acorral]

As I move forward eliminating the bryopsis algae on my display tank, I'm getting some black cyano mat on my sand bed... is this normal behavior when getting rid of the algae or something isn't right?

[srusso]

Great news!

[acorral]

Great news!
Yes Srusso, thanks to the UAs and you personal advice I'm getting rid of the Bryopsis... what do you think about the Cyano ??? is that part of the process of getting rid of the algae ???

[SantaMonica]

You could add hours, since the growth is not bright green.

Point a powerhead near the sand to clear the cyano.

[acorral]

Good news !!!

Bryopsis is 90% death !!!! I guess the die-off from the bryopsis was fueling some cyano or dinos on the sand (not sure if it was cyano or dinos or both)

I have been sweeping the sand lightly with a powerhead once a day

Added some fresh activated carbon

Renewed my UV bulb and lowered the flow on it to make it more effective on rising ORP

And today I finally saw white sand witout any cyano or dinos, just with some light debris on it that I siphoned out !!!

I expect to have finally defeated the bryopsis algae at 100% in something around 2 weeks

After that I plan on keeping the same feeding and scrubing regime fro 3 months to make sure Bryopsis is gone and then I will start rising the feeding again to my corals and fish, at that point I may also consider changing from UAS to ATS to take advantage of the extra oxigenation on the ATS and be able to shut down my skimmer... not sure right now but I may go skimmerless in some time !!

[tebo]

Acorral hermano de verdad es una buena noticia lo que colocas, dios quiera que ya en 3 semanas veamos ese acuario sin bryopsis

Lo de la ciano estoy seguro que son los desechos que deja la bryopsis que nadie más efectivo que la ciano, pero como bien dices era algo pasajero

Ahora recuerda que la oxigenación que se comenta por el ats no es tanto por el movimiento si no por la misma alga que inyecta oxigeno directamente en la columna de agua, así que uas o ats creo sería lo mismo con respecto al oxigeno; aunque puede afectar el crecimiento, como te comente antes, al uas lo que todavía no veo es un buen crecimiento de alga, aunque esto pueda que no tenga que ver con consumo de nutrientes, no lo sé, abría que experimentar

Saludos y un gusto saber que vas ganado la batalla

[kerry]

My Spanish is almost non-existent. I dont know what you are trying to say about the oxygen and growth. This should not really effect the Bryopsis or the cyano.
bryopsis is hard to beat even with a scrubber!!! Its tough for sure.
Congrats on your battle. I still have a little tuft of it pop every now and then.

[tebo]

HI kerry, I am trying to say is that the UAS as ATS provide the same amount of oxygen to the water

that's all

[acorral]

Cotinued using the UAS to kill the bryopsis but it persists in 3 rocks still and in some sections of the back glass that is covered in coralline algae...

I guess the UAS is not performing properly, I have been increasing the light period and still don't get bright green algae... I guess that is perhaps caused by the 2 sided design that implies indirect light going through 7 inches of water column... I'm considering doubling the light and the screen size and convert it back to 1 sided... also because the 2 sided setup takes too much effort to clean the mirrors...

The other option I'm considering is converting it to 1 sided with the current light output and screen size and add an ATS to the system to compoensate for the capacity loss on the conversion to 1 sided.... I guess that would also work as a test between UAS and ATS... to see if one of them could outcompete the other one, perhaps proving which one is more efficient...

For now these 2 options are just ideas... I'll keep you posted...

[SantaMonica]

You can keep increasing the light until the growth turns yellow.