Algae Scrubber Advanced
- Thread starter maglofster
- Start date
herring_fish
Crazy Designer
http://www.sciencedirect.com/science/article/pii/S0272771409002935
When I copy and paste your link with the tags, it works fine.
I don't have a comment on UV but I would add that scrubbers that are working well, product oxygen levels quite near the saturation point.
When I copy and paste your link with the tags, it works fine.
I don't have a comment on UV but I would add that scrubbers that are working well, product oxygen levels quite near the saturation point.
Last edited:
herring_fish
Crazy Designer
Abstract
The quantity of chromophoric or coloured dissolved organic matter (CDOM) released by eleven species of intertidal and sub-tidal macroalgae commonly found on UK shores was investigated. The subsequent breakdown of CDOM was also measured by exposing collected CDOM samples to light and dark conditions for over two weeks. CDOM absorption properties were compared at a fixed wavelength of 440 nm and across two integrated wave - bands; UV-A (400"“315 nm) and UV-B (315"“280 nm). Absorption spectra of macroalgal CDOM samples were typically characterized by peaks and shoulders in the UV bands, features which were species specific. The spectral slope, derived using the log-linear method, proved to be very specific to the species and to the effect of light. Slope measurements ranged from 0.010 to 0.027 nm−1, in the range of normal seawater values. Significantly more CDOM was produced by algae which were illuminated, providing evidence for a light driven exudation mechanism. Averaged across all species, exudation in the dark accounted for 63.7% of that in the light in the UV-B band. Interspecific differences in exudation rate encompassed an order of magnitude, with the highest absorption measurements attributable to brown algae. However, some brown algae produced considerably less CDOM (e.g. Pelvetia canaliculata), which were more comparable to the green and red species. Over an exposure time of 16 days, significant photochemical degradation of CDOM was observed using a natural summer sunlight regime, showing that natural solar radiation could be an important removal mechanism for newly produced algal CDOM. Though the most obvious effect was a decrease in absorption, photo-bleaching also caused a significant increase in the spectral slope parameter of 0.004 nm−1.
So they are talking about both the CDOM released side and the diferent amounts of degradation of CDOM but I don't see a comparison of amount released to degraded. What is the net. That would be a little harder to find.
The quantity of chromophoric or coloured dissolved organic matter (CDOM) released by eleven species of intertidal and sub-tidal macroalgae commonly found on UK shores was investigated. The subsequent breakdown of CDOM was also measured by exposing collected CDOM samples to light and dark conditions for over two weeks. CDOM absorption properties were compared at a fixed wavelength of 440 nm and across two integrated wave - bands; UV-A (400"“315 nm) and UV-B (315"“280 nm). Absorption spectra of macroalgal CDOM samples were typically characterized by peaks and shoulders in the UV bands, features which were species specific. The spectral slope, derived using the log-linear method, proved to be very specific to the species and to the effect of light. Slope measurements ranged from 0.010 to 0.027 nm−1, in the range of normal seawater values. Significantly more CDOM was produced by algae which were illuminated, providing evidence for a light driven exudation mechanism. Averaged across all species, exudation in the dark accounted for 63.7% of that in the light in the UV-B band. Interspecific differences in exudation rate encompassed an order of magnitude, with the highest absorption measurements attributable to brown algae. However, some brown algae produced considerably less CDOM (e.g. Pelvetia canaliculata), which were more comparable to the green and red species. Over an exposure time of 16 days, significant photochemical degradation of CDOM was observed using a natural summer sunlight regime, showing that natural solar radiation could be an important removal mechanism for newly produced algal CDOM. Though the most obvious effect was a decrease in absorption, photo-bleaching also caused a significant increase in the spectral slope parameter of 0.004 nm−1.
So they are talking about both the CDOM released side and the diferent amounts of degradation of CDOM but I don't see a comparison of amount released to degraded. What is the net. That would be a little harder to find.
Last edited:
SantaMonica
Well-known member
I understand these thing can occur, but they are not occurring in an important amount.
This has probably been discussed, if I am dosing kalk, when would be the best time to do it? It seems as though doing it at night might not be the best solution if that is when I am lighting my ats. Thoughts? When should I dose kalk? small dosage during 24 hours? during the off hours of the ATS or during the lighted hours of the ATS. Thank you in advance.
Second question, would if be more beneficial to run the ats light on a 2-6 hour schedule with a hour or so break in between, or for 12 hours on and 12 off?
Second question, would if be more beneficial to run the ats light on a 2-6 hour schedule with a hour or so break in between, or for 12 hours on and 12 off?
Floyd R Turbo
Either busy or sleeping
1) I think it's safe to dose kalk when your scrubber light is on.
2) Whatever works best. Generally, I recommend the split photoperiod if you are starting up a scrubber and having trouble getting algae to start growing. This is usually only a problem when running a powerful / dense LED array where you start to get photosynthetic saturation when you don't have much algae. Once you get a lot of growth, this is less of a factor (and you can combine the photoperiods into one). So far I have seen no one report a measurable long-term benefit for having multiple shorter photoperiods, aside from not burning algae as described above.
2) Whatever works best. Generally, I recommend the split photoperiod if you are starting up a scrubber and having trouble getting algae to start growing. This is usually only a problem when running a powerful / dense LED array where you start to get photosynthetic saturation when you don't have much algae. Once you get a lot of growth, this is less of a factor (and you can combine the photoperiods into one). So far I have seen no one report a measurable long-term benefit for having multiple shorter photoperiods, aside from not burning algae as described above.
crazzyreefer
New member
One thing to consider the screens your using are NOT UV stable, only the black screens are, so I wouldn't bombard them with UV lighting.
I finally found a source for PPE screens in roll form, replacing the heavy fiberglass screening, Some time early this week we should get the 10 feet of screening installed in to the system, and see how it goes. If it all goes well I will let everyone know where to buy the screening.
I will also update if Co2 in the grow chamber increases the growth any
I finally found a source for PPE screens in roll form, replacing the heavy fiberglass screening, Some time early this week we should get the 10 feet of screening installed in to the system, and see how it goes. If it all goes well I will let everyone know where to buy the screening.
I will also update if Co2 in the grow chamber increases the growth any
crazzyreefer
New member
Also might want to note that everyone should monitor their ph, with the scrubber on, we are at 8.6 ph, so I can dose for the co2 reactor, when the scrubber is off I can dose from the kalk reactor.
Floyd, it is a misconception that a ATS isn't working when filling, it is, but not at the same level of efficiency when it is dumping.
Floyd, it is a misconception that a ATS isn't working when filling, it is, but not at the same level of efficiency when it is dumping.
crazzyreefer
New member
Only so that my ph does not rise any more that the almost fixed 8.6 readings. But keep in mind this is a vary large system, it utilizes 3360 sq inches of screening X 2 = 6720 sq inches powered by 14 panels of led lights.
Floyd R Turbo
Either busy or sleeping
Good to know, thanks for sharing. So if one would shine UV on a non-UV stabilized screen, what could happen to the material?
Do you mean the knitting canvas in roll form? This stuff is actually linear low density polyethylene, commonly called LLDPE. I had to look up "PPE" and I'm not sure that's the same stuff, if it is actually "PPE"
That's what I meant - the efficiency is much lower. With your huge scrubber, it takes a long time to fill, IMO that makes a big difference. But someone else is doing the same thing on a much smaller unit (1 gallon) and it seems to work pretty well
crazzyreefer
New member
The scrubber is a large waterfall type, not submerged. PPE is starboard material, PPE has good UV protection, and tensile strength, UV does affects it by dulling and fading of color, or yellowing. LLDPE has a low tensile strength, and is affected by UV, Warm water, and resulting in Hydrolization. The last effect is a process of the resins converting back into ethanol. I have experienced this first hand, and the process turns plastic into a gel that smells like acetone. This process is common on sail boats, but it affects all LLDPE plastics the same way. I would not classify LLDPE reef safe.
Floyd R Turbo
Either busy or sleeping
People have been using plastic canvas for literally decades. You're telling me that they're all running material that is not reef safe?
crazzyreefer
New member
Sorry Floyd, yes I am.. No, this isn't meant to attack your work. But unfortunately not all plastics are not meant to be bombarded with light, UV or even submerged under water. Plastics degrade, some in decades, other in matter of months. Warm Salt Water has a strange effect on plastics that I never knew about until I had to
50k to repair the hydrolization of the top sides, I began to research it and properties that lead to it. I didn't expect to find that it was common, but unfortunately it was and it made me research other plastics I use on the tank. I have found that PPE more or less is safe but LLDPE isn't. The effect on a sail boat is easy to detect, it's painted surface encapsulates the resins, and is easy to see the negative results, it isn't easy to detect when its not covered by a barrier that traps the deteriorating plastics. But make no mistake the same process is happening, just it entering into the water column.
50k to repair the hydrolization of the top sides, I began to research it and properties that lead to it. I didn't expect to find that it was common, but unfortunately it was and it made me research other plastics I use on the tank. I have found that PPE more or less is safe but LLDPE isn't. The effect on a sail boat is easy to detect, it's painted surface encapsulates the resins, and is easy to see the negative results, it isn't easy to detect when its not covered by a barrier that traps the deteriorating plastics. But make no mistake the same process is happening, just it entering into the water column.
Floyd R Turbo
Either busy or sleeping
I didn't consider it a personal attack, because I'm not the one that first suggested using it. I would have to check but I'm pretty sure that thus stuff has been used as far back as Dr Adey. I know that Inland Aquatics uses it because I've ordered seeded screen sections from them. So I really don't think there is a whole lot to worry about, honestly.
crazzyreefer
New member
We used inferior glues/sealant, 30 years ago too, some people still use the metal frame tanks, I wouldn't. Plastics are changing due to landfill issues, additive are incorporated so that they will break down in a land fill. The plastic that was used years ago isn't the same as the plastics used now, looks the same, but different in composition and production. Quality control has changes in the last decade, a product that would last is now produced with inconsistencys, along with unstabilized production methods.
I am well aware of inland's setup, over great scotch I got to know Morgan, I can't disagree his system works. But as time changes so is the materials he is using, now the system is also changing, lighting is much more intense and focused in narrower spectrum, even the process is changing, allowing the screens to hang and cleaning them daily changes the exposure and thus changes how fast they degrade.
People still make and use plywood tanks, Epoxy coated. Not once did they take into account that the dried resins would turn back into liquid form. Now a 12x12 screen isn't the same as a whole tank made of resin, but it still leaches. You don't get a lot of UV light up there in IA, but if you were on a tropical island you would see first hand what the sun does, we are multiplying this effect with new lighting. I was badly burned and suffered temporary loss of vision wile working under my light last week, it only took 10 min. I forgot to tun them off when I was moving some rocks, hard lesson to learn.
I found a PPE screen provider, It is much safer to use, but testing still needs to be done to be sure if its will work for me.
I am well aware of inland's setup, over great scotch I got to know Morgan, I can't disagree his system works. But as time changes so is the materials he is using, now the system is also changing, lighting is much more intense and focused in narrower spectrum, even the process is changing, allowing the screens to hang and cleaning them daily changes the exposure and thus changes how fast they degrade.
People still make and use plywood tanks, Epoxy coated. Not once did they take into account that the dried resins would turn back into liquid form. Now a 12x12 screen isn't the same as a whole tank made of resin, but it still leaches. You don't get a lot of UV light up there in IA, but if you were on a tropical island you would see first hand what the sun does, we are multiplying this effect with new lighting. I was badly burned and suffered temporary loss of vision wile working under my light last week, it only took 10 min. I forgot to tun them off when I was moving some rocks, hard lesson to learn.
I found a PPE screen provider, It is much safer to use, but testing still needs to be done to be sure if its will work for me.
salty joe
Active member
Not saying it aint so, but that's news to me. Is this akin to the, the sun will die out some day, type statement? In other words, the kind of thing that does not matter in a human's lifespan. It's my understanding that the resin does not dry, it cures.
I've heard of epoxy tanks running for decades.
JustinGr
Clown Pimp
UV will make some plastic brittle and yellow. It becomes unstable. The plastic egg crate people use for lids and under LR is a good example. Under UV producing light it will deteriorate within a year. I've had several pieces under LED and they look new compared to the stuff under UV producing light.
I think the key here, is the UV light causing degradation in the plastic. LDPE is rated as "Excellent" for seawater http://www.coleparmer.com/Chemical-Resistance
Luckily, we push towards the red spectrum (if not exactly red) with most of the lighting for these turf scrubbers, so UV should be minimal, being on the opposite side of the visible spectrum.
