SURF2 and SURF2

[SantaMonica]

The sweet spot is simply to watch the growth, and adjust the light accordingly. That's the beauty of the timer

[scolley]

Thanks for the reply. But if I'm understanding the issue, it does not answer the question...

I get the fact that increasing the photoperiod will help reduce high nutrients (as evidenced by black algae) faster. But the low nutrient problem's remediation was not changing the photoperiod, but was to reduce the light intensity. As I understand it, in higher order plants these do not equate to the same thing (halving photoperiod does not equate to halving light intensity). Maybe that's not the case with algae, and reducing photoperiod should have been mentioned as a remediation method along with the various means of reducing intensity?

Either way, IF it is true that too many nutrients is a problem. AND IF too few is also a problem. AND IF you could get a broken in screen in SURF2 14 days then THEN there must be some happy medium of nutrient levels that allowed a 14 day break in - less than too many and more than too few. If those statements are true, then can you please describe what that level is? In PPM of some measurable nutrient?

Also, I asked if the "too few" nutrients problem caused by nuisance algae applies equally to a tank that had similarly low nutrient levels, but was caused by a well functioning ATS instead. Would love an answer to that please.

Thanks.

[Floyd R Turbo]

Scolley, I totally appreciate your questions here. I'm going to try to answer these based on what I have seen in results from customers of mine who run the waterfall scrubbers, as well as my personal experience. Also this is only considering the case of growth spectrum LEDs.

It seems that the 'break in' period is the difference here. What I theorize based on the anecdotal evidence is that when you have a bare screen/substrate, and blast it with high intensity light for a long photoperiod, you get no growth, or very slow growth. It seems that when there is little to no algae to absorb the incident light, it immediately becomes photo saturated, and stops growing all together. The solution is to either reduce the intensity, or reduce the photoperiod. The latter is usually recommended because the former requires a different driver.

In the case of my first revision of my algae scrubber, I put 6 reds 2" on center and a single full-current (700mA) blue in the middle, and used a diffuser as well. Almost without exception, everyone got a bare spot right in the middle of the screen, directly in front of the blue. The solution was to add a black dot with a sharpie or a piece of tape over the blue. This knocked down the intensity and the screens filled in. Once the screen filled in everywhere and growth was good, one could remove the diffuser and growth was not inhibited, as there was plenty of algae to absorb the incident light.

So ideally, the HP LEDs, you do indeed want to reduce the intensity in order to encourage initial growth. After that, it's game on, as long as the nutrients are there for the growth to occur.

Your questions regarding the perfect balance of nutrients required to get the 14 day from zero-to-hero growth are very good, but you likely won't get an answer, because to get this answer requires much scientific testing, none of which anyone has done, really. I can show you examples of people running my scrubbers that go to solid green in 10 days, and others that can't get green to save their life. Everyone's tank is different and I think this is the difficulty. This is why you see examples of people going months with very little growth and struggling to figure out why their didn't go green in 14 days like it did in the product page pics.

So the answer is...we don't really know, exactly, but we can draw pretty good conclusions from what we have experienced. Lack of one nutrient can cause the whole process to stall out. Limitations in N, P, K, and/or many other trace elements can throw things off. This is one of the frustrations, none of this stuff has really been studied in a well controlled scientific manner.

My theory on the algae scrubber is that growth is a direct reflection on the health of your system. If you get gob of green growth, then you're doing things right. If you are having trouble growing green, it's likely not the algae scrubber's fault - something is out of balance in your system. I think if more people were looking in that direction, we might have more answers to questions like yours.

...now I know you're going to have more questions!!

[SantaMonica]

This is to a large amount what I would have said, with the addition of "photoinhibition". With hardcore photoinhibition, there is too much light for the amount of nutrients. A reduced period won't help, because then it either off, or photoinhibited, neither of which grow. The answer is to dim the light, which normally you never want to do because dim light causes celluose growth to slow and exudates to increase, neither of which removes nutrients.

Another component is organics. Some are consumed by algal growth, especially cladophora, which grows a lot in a SURF2. So this unseen and un-measurable component alters things too, and also feeds into the photosynthesis process.

Thus, the easy solution is to temporarily reduce the light.

[scolley]

Great replies! Thank you.

But I'm going to have to beg indulgences of you guys. I'm on the right coast. Floyd in the middle and SantaMonica on the left coast. And it's getting late here. So rather than get a reply wrong, please allow me to get back to you on the morrow.

Thanks again! More soon...

[Floyd R Turbo]

Photoinhibition is a technically incorrect term. Photo Saturation is what actually happens. The cells get saturated with production and cannot perform the secondary process.

...and I have found that reducing the photoperiod does indeed help. Again, only on startup. But what I theorize happens is that during the 'on' period, you get some algae growth started that is not quite visible yet, but if you leave the photoperiod on for too long, this algae becomes to saturated that it is just overwhelmed and dies off, and your screen stays white. Algae will (I should say 'may', but there is evidence that it does happen) continue to grow after the lights are off, so giving it a short photoperiod then allowing recovery will get it started in situations where it is taking longer than it should.

Even a better way to start it would be to flash the algae. Ideally, you would flash at a very high rate like Otto Warburg did in the 1930s with his experiments, which were expanded upon in later years. Flashing at a 1kHz rate with a dark period that is 10x longer than the light period results in the same production rate as constant light, without photosaturation. But, with LEDs on a waterfall scrubber, we are already likely getting this effect because of the sheet water motion. On startup though, this is where a flashing type of cycle may improve the growth rate. You could simply put a timer on your LEDs so that they were on for 3s and off for 1/2s and see what happens. No one has done this yet, and it would be hard to see the effectiveness without a control group.

But the concept is that light causes one bucket to 'fill' and this bucket must be 'emptied' before it can fill again. The 'emptying' is done during the dark period (hence know as the dark process or dark cycle) and without that dark period, the bucket can only overflow. Giving a startup screen this dark period may effectively eliminate the photosaturation effect and cause a screen to start faster in a given environment

[scolley]

OK. Thanks again for your replies. Let me see if I can recap where my questions stand, and move them forward. The essence of my prior questions were -

"If excess nutrients causes one startup problem, and too few nutrients causes another, what is the sweet spot found in the advertised 14 day breaking in?"
"How is the low nutrient problem caused by nuisance algae any different than a tank that has low nutrients from an ATS?"

And my question in response to the first reply, "Why are you recommending a modified shorter photoperiod now, when the recommendation for low nutrients was reduced intensity? They are not the same."

Let's start with the 3rd question above - about photoperiod vs intensity. Your answers all appear to indicate that reduction in intensity is the answer for a low nutrient situation. They further indicate that it may be appropriate for the startup period in general due to photo inhibition/saturation. That implies that the post suggesting photoperiod adjustment was incorrect - intensity reduction is more appropriate. However, since SantaMonica got a good startup SURF2 in 14 days with no mention of intensity reduction, then clearly it is not needed in all situations. Which leads us back to my initial question - the 1st question restated above about the nature of the 14 day break in sweet spot...

If we take SantaMonica's break in as factual (I do), then we can assume that photo inhibition/saturation does not always occur at levels that require reduced light intensity. As Floyd stated, whether a given system is able to support a fast startup is limited by the availability of macro and micro nutrients, and trace elements. In reply I understand that totally. Except that I disagree that you can never know. Sometime you should be able to KNOW. In a tank that is supporting a viable ATS, then you should know that a SURF2 has everything it needs to grow algae in that water. And as long as said viable ATS is actively growing algae, then it is not a low nutrient situation. And in all likelihood, it's not a high nutrient situation either. That can be tested - though "too high" has not been quantified.

So in my particular situation - SURF2 replacing a viable, growing ATS in a low (but not no or limited) nutrient system - I should be able to assume I'm giving the SURF2 everything it needs as far as nutrients go for productive algae growth. The only other factors are flow rate and light. But I've volume tested my air supply and trimmed it to just a shade over 5 liters per minute. So that's perfect. That leaves light. And unless SantaMonica deviated from the recommended 18 hour photoperiod recommended in the instructions, with no light intensity reduction, then if I set at an 18 hour photoperiod with the LED lid directly on the SURF2 floating scrubber, I should be a prime candidate for a 14 day break in. Particularly since I seeded the Green-Grabber surface and ribbons with nice green algae from my ATS.

The only thing that would cause me to question that conclusion is my 2nd, restated question above regarding the difference between a nuisance algae caused low nutrient tank and an ATS caused low nutrient tank. Since that question has still not been answered, it appears that I have no choice but to begin making assumptions...

EITHER a system that has an ATS that is growing nice, green algae does not fall into the category of "light intensity reduction needed, low nutrient, nuisance algae dominated" systems. In which case there should be no action required for me to get a nice, quick break in.

OR having that viable ATS can generate conditions similar to a "light intensity reduction needed, low nutrient, nuisance algae dominated" system. In which case I'll find that my SRURF2 is slow to break in, until and unless I reduce the light intensity.

Well I'm going to find out which it is. My system has no nuisance algae to speak of (though I do have to clean a small film off the glass weekly), and when I set up the SURF2 in in my system, NO3 was < 0.2 ppm, PO4 0.05 ppm. And I turned the ATS off - it's not competing. In 10 days or so, we should know if it's kicking in.

Thanks for the help.

[scolley]

If you concur with my above post, a post in agreement would be most appreciated. Likewise, if you disagree with my conclusions, a post clearly explaining why would also be much appreciated.

Our goal should be clarity and understanding. I'm not remotely concerned about being "right" or "wrong" personally. I seek clarity through detailed, fact based discourse. My primary concern is making sure the community has clarity around these questions.

Thank you.

[Floyd R Turbo]

Except that I disagree that you can never know. Sometime you should be able to KNOW.

When I say that you can never know, what I meant was that we only test a limited subset of parameters. The system is not that simple, and there may be something in particular that we don't or can't normally test for (due to expense, complexity, etc) and that item's level may adversely affect growth in the short term and possibly the long term.

In a tank that is supporting a viable ATS, then you should know that a SURF2 has everything it needs to grow algae in that water.

It is my contention that growth on submerged scrubbers (UASs) and vertical/waterfall scrubbers do not correlate directly due to the different implementation. So the statement above is based on the assumption that they are one and the same, which they may not be.

Our goal should be clarity and understanding

I wholeheartedly agree

[scolley]

Thanks for the reply!

It is my contention that growth on submerged scrubbers (UASs) and vertical/waterfall scrubbers do not correlate directly due to the different implementation. So the statement above is based on the assumption that they are one and the same, which they may not be.

Yup. I get that. Thanks. ATSs/UASs - apples/oranges - not necessarily the same. However, in dealing with the question of the conditions necessary to get a SURF2 productive in a system successfully running an ATS, IMO any differences are irrelevant. Here's why...

Marine algae needs (broadly speaking) needs two or three things to grow; light, nutrients, and possibly water movement.

In the SURF2 water movement should not be variable - it's governed by the bubble rate. Get that rate set as defined in the instructions (and I have), and it's set. Whether or not that movement is different that of an ATS in that same environment is immaterial. 5 LPM has been determined to be sufficient. Based on the information so far provided, set the air supply to 5 LPM and it's done.

Light too is not variable in the case of a SURF2. Or at least I'm ASSUMING it's not. The instructions call for an initial 18 hour photoperiod, with nothing done to reduce the intensity of light. A 14 day break in progression has been published - here's where my assumption comes in - and I assume that that progression was achieved the same way as the instructions call for. I.e. - 18 hour photoperiod, no intensity reduction. If that's not the case I'd love to know. But again, how this differs from light provided to an ATS in the same environment is not particularly relevant.

And finally nutrients. If the nutrients were right for growing algae in an ATS, then that same water has the right nutrients for growing algae in ANY other mechanism using that water that is otherwise able to do so. I do believe that is an absolute.