Algae Scrubber Basics

[inky]

Nice succint post

How does the 1W per square inch light translate to LEDs? Could we convert the wattage to lumen per square inch, or would that be irrelevant? Sorry, I can't figure out the conversion factors at the moment

My LED scrubber is going OK, not fantastic growth I have 6 2700K whites on one side and 6 reds on the other, not sure of the red spectrum (Luxon LEDs). Both seem to grow about the same amount Thinking I might need more light, as flow shoul be plenty - it's certainly not lacking flow....

Updated the threads on other sites with this, so just for consistency:

New Scrubber Sizing Guideline (Sept 2011)

Scrubbers will now be sized according to feeding. Nutrients "in" (feeding) must equal nutrients "out" (scrubber growth), no matter how many gallons you have. So...

An example VERTICAL waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

1 frozen cube per day (2-sided screen)
1/2 frozen cube per day (1-sided screen)
10 pinches of flake food per day (2-sided screen)
5 pinches of flake food per day (1-sided screen)
10 square inches (50 sq cm) of nori per day (2-sided screen)
5 square inches (50 sq cm) of nori per day (1-sided screen)
0.1 dry ounce (2.8 grams) of pellet food per day (2-sided screen)
0.05 dry ounce (1.4 grams) of pellet food per day (1-sided screen)

High-wattage technique: Double the wattage, and cut the hours in half (to 9 per day). This will get brown screens to grow green much faster. Thus the example above would be 12 watts on each side, for a total of 24 watts, but for only 9 hours per day. If growth starts to turn YELLOW, then increase the flow, or add iron, or reduce the number of hours. And since the bulbs are operating for 9 hours instead of 18, they will last 6 months instead of 3 months.

HORIZONTAL screens: Multiply the screen size by 4, and the wattage by 1.5

Flow is 24 hours, and is at least 35 gph per inch of width of screen [60 lph per cm], EVEN IF one sided or horizontal.

Very rough screen made of roughed-up-like-a-cactus plastic canvas.

Clean algae off of screen every 7 to 14 days, so that you can see the white screen material.

 

[srusso]

Just cleaned my first week's gunk off the screen. Had to relocate 5 snails that hitched the ride out of the tank via the screen. Too bad for them they are now in an entirely separate system and no more screen munchies provided.... Took front and back pics of it for input.

Stat:
6.75" wide, 10.5" long. Roughly sized for 2 cubes a day.
2x 13W 2700K lights on both sides, with reflectors.
15 hours of light, inverse of main lights, but willing to tweak if necessary.
Flow unknown; it looks right and is provided by a Maxi-Jet Utility 1800 (474 gph rating) which at half rating is 35 gph per inch.

Looks like normal growth for week 1, thanks for posting.

 

[scolley]

Nice succint post

How does the 1W per square inch light translate to LEDs? Could we convert the wattage to lumen per square inch, or would that be irrelevant?

For LEDs using wattage is likely not the best metric since performance of light per watt varies by LED. Your suggestion of lumens is likely the best metric, though that info can be hard to find some times. For instance Cree publishes the luminosity of their XR-Es that I'm using at 107 lumens, but that's when run them at 350ma. My driver runs them at 700ma, and it took a bit of research to determine that they were pushing 135 lumens at that amperage. So lumens is likely a good metric, but you have to be careful and be sure you know what you are measuring.

Also, if it's not an LED that will grow algae well (given sufficient light) the lumen per sq. inch exercise is a waste of time.

And another factor that you have to be really careful about is the utilization of that light. All my light does not hit my screen, there is a lot of loss of all that light. That will depend on the ATS setup.

I can say, what works very well for me is roughly 33 LED lumens per square inch of screen (single side). My guestimate of how much light is lost, never hitting the algae is MORE than 1/3 wasted.

So if you can direct ALL of your light to your screen, and if you can know how many lumens your are generating, and if you have selected an LED that will grow algae well in sufficient quantity, then 22 lumens per square inch should be more than sufficient.

...if my calculations/estimations are correct.

 

[inky]

For LEDs using wattage is likely not the best metric since performance of light per watt varies by LED. Your suggestion of lumens is likely the best metric, though that info can be hard to find some times. For instance Cree publishes the luminosity of their XR-Es that I'm using at 107 lumens, but that's when run them at 350ma. My driver runs them at 700ma, and it took a bit of research to determine that they were pushing 135 lumens at that amperage. So lumens is likely a good metric, but you have to be careful and be sure you know what you are measuring.

Also, if it's not an LED that will grow algae well (given sufficient light) the lumen per sq. inch exercise is a waste of time.

And another factor that you have to be really careful about is the utilization of that light. All my light does not hit my screen, there is a lot of loss of all that light. That will depend on the ATS setup.

I can say, what works very well for me is roughly 33 LED lumens per square inch of screen (single side). My guestimate of how much light is lost, never hitting the algae is MORE than 1/3 wasted.

So if you can direct ALL of your light to your screen, and if you can know how many lumens your are generating, and if you have selected an LED that will grow algae well in sufficient quantity, then 22 lumens per square inch should be more than sufficient.

...if my calculations/estimations are correct.

Yep, understood Running about 700ma with Cree XP-E, so maybe 100 lumen from each, need to check that!

I chose the whites for their red and blue spectrum, from the Cree data sheet (I get confused as to warm/cool/natural/neutral whites), 2700K seemed to be the bst spectrum for the chorophyl A and B.

I have no lens' at the moment, so am wasting a lot of light as well. May well try putting some lens' on them to focus the light more, but that could provide spot growth..... The other thing I've been looking at is using mirror acrylic to create a reflector and prevent loss of light. This could provide more light to the whole area.

 

[TheFishMan65]

Scolley,

Is there a typo in this?

My driver runs them at 700ma, and it took a bit of research to determine that they were pushing 135 lumens at that amperage.

Doesn't seem right, but I did not actually look up all the numbers.

Thanks

 

[Floyd R Turbo]

Here's a funny shot I took yesterday during trick-or-treat. I plugged in one of the LED scrubber lights I had made and pointed it at the front window

My wife said it looked more Barbie than spooky. lol.

 

[TheFishMan65]

I kept having kids down down the front porch to look in the dining room window. I would catch them and they said nice house. Later on some commented on the cool spooky lights (Royal Blue LEDs over the tank). So I think that is what the little ones were checking out.

 

[scolley]

Scolley,

Is there a typo in this?

Doesn't seem right, but I did not actually look up all the numbers.

Thanks

The 700ma is correct - easy to look up. Here's my original math...

12 LEDs @ 3watts running 700ma = 135 lumens per LED x 12, or 1620 lumens
​

1620 lumens / (6" High x 8" wide) screen = 33.75 Lumens per screen sq. in.

33.75L/sq. in. times .666 light actually hitting the screen = 22.3 L/sq. in on the screen
​

But what might be wrong is my 135 lumens per LED number. I got it at this website here. And I question it now because it shows the XR-Es at around 72 lumen run at 350ma, when we know it to be 107. So if the entire curve at that site is low by 35 lumens (major assumption). Then my LEDs are burning at 170, making my actual burn 42.5 lumens per sq. in, not 33.75. A lot of assumptions and uncertainly there.

Maybe the best bet is to shoot for that 42 lumen target (or 28 w/100% coverage), and back your photo period down if it's too much. I'm running a reverse photo period now - so only about 14 hours a day.

 

[TheFishMan65]

XR-E at 350 ma can be 107 lumen if you use CW and the R5 bin. My question is were did you get the 135? Looking at the CREE XR-E datasheet at 700 ma the output is increased to 160+%. So 107 * 1.6 = 171 lumens. Did you derate for heat or something?

Oh, look if I just read a little further (rather than jumping on the 135).

Also are you running CW? I can't remember.

 

[scolley]

Yes. Primarily CW. Possible that there is a NW or two in the set of twelve. Also I've got two deep reds. However this is my 2nd such fixture. The first was all XR-E CW and it grew algae pretty darn well too.

 

[chatyak]

Alright, I've skimmed this thread and I'm considering doing an algae scrubber for my 125 display. I have a 30 gallon sump plus a 30 gallon brute that is used for a RDSB, but I still get film algae on the glass and I have stubborn cyano that will NOT go away.

 

[pskelton]

Alright, I've skimmed this thread and I'm considering doing an algae scrubber for my 125 display. I have a 30 gallon sump plus a 30 gallon brute that is used for a RDSB, but I still get film algae on the glass and I have stubborn cyano that will NOT go away.

Sounds like you have come to the right place

 

[Floyd R Turbo]

You will never find anything that completely eliminates diatom algae on the glass. You just have to deal with scrubbing that off. But if you're talking about the stuff that comes off in pieces/sheets when you scrape it, a scrubber may reduce that.

As far as cyano, that's a tough one no matter what. What you need is a very strong scrubber, and by that I don't mean necessarily large, just properly built. Size it based on how much you feed now, build one the less expensive route (just pipe, screen, CFLs reflectors) but make sure the flow is good and there is plenty of light. Go 'cheap' first, build small and powerful, then if you like how it works, built a bigger better one that can handle more bioload (if you want to)

For instance, if you feed 2 cubes/day, you need 24 sq in (dimensionally) or 4x6, 8x3, etc, figure out a flow rate you can achieve and divide by 35 to get your width, then get 2 23W or 26W CFLs and good reflectors, lights on for 9 hours/day (new lighting regimen).

Read posts 2001-2010 and the last few weeks or so of posts regarding feeding screen sizing and reduced photoperiod/increased wattage

 

[chatyak]

You will never find anything that completely eliminates diatom algae on the glass. You just have to deal with scrubbing that off. But if you're talking about the stuff that comes off in pieces/sheets when you scrape it, a scrubber may reduce that.

As far as cyano, that's a tough one no matter what. What you need is a very strong scrubber, and by that I don't mean necessarily large, just properly built. Size it based on how much you feed now, build one the less expensive route (just pipe, screen, CFLs reflectors) but make sure the flow is good and there is plenty of light. Go 'cheap' first, build small and powerful, then if you like how it works, built a bigger better one that can handle more bioload (if you want to)

For instance, if you feed 2 cubes/day, you need 24 sq in (dimensionally) or 4x6, 8x3, etc, figure out a flow rate you can achieve and divide by 35 to get your width, then get 2 23W or 26W CFLs and good reflectors, lights on for 9 hours/day (new lighting regimen).

Read posts 2001-2010 and the last few weeks or so of posts regarding feeding screen sizing and reduced photoperiod/increased wattage

Hey Floyd,

I'll take some pictures and post them later as it will be more clear. Also, I think I should increase the flow to my RDSB as well. That could be an issue I overlooked too...

 

[Floyd R Turbo]

PWCs: An issue worth noting

PWCs: An issue worth noting

As with many on the forums, I am still learning things as I go. A discussion on another site regarding water chemistry has made me aware of something, and I thought it was worth bringing to the attention of everyone.

I have been using the BRS Calcium and Alkalinity (and Magnesium, occasionally) products to maintain my levels, and have not had the need to do PWCs in order to reduce nutrients, and I feed a good quality food, so I haven't felt the need to replenish trace elements either. Due to "salinity creep" I have had to adjust my salinity downward by removing some water and adding RO/DI and until now did not see a problem with this. However, there is a problem with this method.

What happens is that the Calcium Chloride and Sodium Bicarbonate add the necessary calcium and carbonate that are used up by the system, but the sodium and chloride ions are not. What you end up with over time is a skewed ratio of these ions, and the system goes out of balance. Theoretically, if I were to continue the aforementioned method, I would have a ionic solution of only chloride and sodium - all other ions present in seawater, natural or artificial, would be essentially pushed out of solution. If I were only adding one of the two solutions, or more of one than the other, this would be even worse.

The answer to this issue is to use Kalwasser or a Calcium reactor, or something like B-ionic, essentially a method that replenishes the calcium and carbonate without skewing the ionic balance. Rely on BRS type additives only for periodic adjustments when necessary.

If you rely on BRS type additives (calcium chloride, magnesium chloride & sulfate, sodium carbonate/bicarbonate, etc) to maintain levels, I am now recommending that you maintain a regular PWC regimen in order to keep things in balance (things that you can't test for without expensive equipment). This depends of course on how much you need to dose, and I don't quite have a handle on this yet. Myself, I am dosing upwards of 60 ml/day of both Cal and Alk in a 120 gallon system (really about 90 gallons when you figure actual tank capacity minus rock) so the first thing I'm going to do is a big PWC. For me, this is not an issue, since I'm moving the entire system in a week or two, and it's going up 25% in capacity so it will likely be a large PWC anyways. Then I will be doing at least 10% per month until I can get Kalk or Cal Reactor going, and I may continue to do that just for good measure.

 

[Floyd R Turbo]

This is still developing a little as the conversation about this issue continues. My initial reaction of needing 10% per month to maintain ionic balance may have been a bit much, it may require much less than that, but it all depends on how much you dose (if you're dosing BRS type additives)...

Still, 10% per month, for most, isn't that much. It's when you get to the very large systems that it becomes a lot (but still a lot less than 20%)...

 

[Gorgok]

Got a link to this discussion? I, as you, do little to no water changes, just adjust for salinity because of a little drift here and there really. But so far i have not been dosing much of anything either as the tank is not consuming much, yet. Once it starts i need to pick a way to keep it in check, and so far 2 part seems the easiest and before now the safest.

 

[srusso]

Got a link to this discussion? I, as you, do little to no water changes, just adjust for salinity because of a little drift here and there really. But so far i have not been dosing much of anything either as the tank is not consuming much, yet. Once it starts i need to pick a way to keep it in check, and so far 2 part seems the easiest and before now the safest.

You should start researching kalk, for when your tank does start consuming it.

 

[Floyd R Turbo]

Can't link to it 'cause RC blocks links.

 

[srusso]

I am going to start developing a theory I have been conjuring up... Basically its that the screen and growth for the week, acts much like a "dip stick" or "status check" for your tank.

For example: (not an actually known to be true) if your mature screen grows more slimy growth during a particular weeks harvest, it may mean high levels of bacteria.

Or a sudden change in growth to dark algae, with low mass may mean there is a contaminate in the water or that your pump may need cleaning.

Not even really a theory at this point but looking for ideas on how I could began testing this...