Algae Scrubber Basics

I would say that for that fixture on that screen, your growth is pretty good, I don't know that I would worry overly much about the growth covering the whole screen. I have one scrubber that had 6x 660s and 1x 440 in the center and that screen had a bare spot dead center for 6 months, it eventually filled in but never quite as good as the rest, but it filtered fine

The real question/goal is not how even your growth is, it's how effective your scrubber is for your system.

Now if I look at it from a pure numbers perspective, you have 8 LEDs that are likely 3W "rated", varying outputs so I would have to guess that the fixture actually pulls about somewhere around 14W off the wall

Screen is huge for that light, 10x13 = 130 sq in, the formula says that you would want 0.25W/sq in of LED light per side or about 32.5, which is at least double what you are using.

I'm not saying that you should change what you are doing, because if it works for you, the goal is met. But you might be able to 1) use a larger light fixture and get more production (if you have the bioload to support that) or 2) reduce the screen size and get a higher flow rate using the same pump, and/or save some space in your sump.
 
Floyd R Turbo said:
I would say that for that fixture on that screen, your growth is pretty good, I don't know that I would worry overly much about the growth covering the whole screen. I have one scrubber that had 6x 660s and 1x 440 in the center and that screen had a bare spot dead center for 6 months, it eventually filled in but never quite as good as the rest, but it filtered fine

The real question/goal is not how even your growth is, it's how effective your scrubber is for your system.

Now if I look at it from a pure numbers perspective, you have 8 LEDs that are likely 3W "rated", varying outputs so I would have to guess that the fixture actually pulls about somewhere around 14W off the wall

Screen is huge for that light, 10x13 = 130 sq in, the formula says that you would want 0.25W/sq in of LED light per side or about 32.5, which is at least double what you are using.

I'm not saying that you should change what you are doing, because if it works for you, the goal is met. But you might be able to 1) use a larger light fixture and get more production (if you have the bioload to support that) or 2) reduce the screen size and get a higher flow rate using the same pump, and/or save some space in your sump.
Click to expand...


P04 never reads higher then .03 and nitrates are zero
 
I knew that but when I start to increase the amount of fish in the tank I will need to feed more. I wanna get this thing growing all green. I will try putting light diffusers in front of the light
 
The issue is that the fixture you have is on a multichip fixture, so the diffuser may not work the way I described it.

I would just give it time, it's difficult to force growth to happen.

My guess is that with that fixture, the LEDs are probably only about 1.25 inches apart - that's way too close. The fixture might be 5.4" wide but that's not the effective spread of the LEDs. So because the LEDs are so close together, they are having an overlapping effect and causing the hot spot. That's a bit more difficult to take care of with a diffuser. It would be better to back the light fixture off so that the light spreads out a bit more, but then you lose a lot of intensity. You could also remove the lenses on at least a few of the LEDs, the target ones being the blue ones and the 630s as those are higher intensity.

What size tank is this on? How much are you feeding?
 
I have 2 ATS installed in my 600g system.
I started with a 2 cube ATS around 5 months ago. that ATS grew algae but it was never very green, is has always been producing a very dark color slimy algae .
1 month ago I installed a 4 cube ATS in the same system while keeping the 2 cube in there becuase I have algae in dt and I am feeding 3 cubes. At first it did not grow much , so I changed light setting to 50% intensity and 1 hour on 1 hour off red led lights. I started increasing the intensity every 3 days after checking that algae started to grow well. I also started to increase led time and now I am doing 110 min on 10 min off. algae is very green in that ATS.

I can not find an explanation of why the 2 cube ATS is growing a different kind of algae?
I am thinking of starting over with the 2 cube. I mean cleaning screen very well and using the same strategy to nurture algae: 50% intensity 1 hour on 1 hour of and increase slowly.

attached is a photo of the 2 cube ATS after 14 days
2 cube side 1.jpg
View attachment 361785


Thank you for your comments
 
I find it kinda weird too, if the L4 is going well then it makes sense to maybe 'reboot' the L2 screen, what I would do if you are going to do that is try it a few times in progressively more aggressive cleaning techniques. i.e. don't overclean it right off the bat, try and find out if a lesser aggressive cleaning does the trick first.

So maybe, scrape all the GHA off very well, then take a toothbrush (like the denture one) and use that with light pressure and small overlapping circles to loosen up algae all over the screen, more so in the areas with the GHA and less so in the areas that are lacking GHA. To take that a step further, choose half of the area that is not growing GHA and only gently clean it, and the other half, clean more aggressively - then future growth will tell you if there is any difference that results from the 2 techniques (there might be, I don't know)

The point it don't scrub really hard so that you are left with a bare screen everywhere, and if there is any mortar left, you will want to try and keep that attached; aggressive scrubbing will remove it all.

Then give it a few cycles and see if the center fills in. If not, then repeat the above but now take a stiffer brush and scrub a bit harder

After a few more cycles, if that doesn't seem to solve the problem, you can scrub even harder and get all the growth off and truly start from scratch.

If you really want to start from square one, soak the screen in vinegar for a few hours, scrub, rinse, then re-coat with mortar (and let it cure and soak)
 
Thanks Floyd,

would it be useful to seed the 2 cube clean screen with some of the GHA from the 4 cube ATS that is on the same system?

if yes, how can I attach the algae to the 2 cube screen?

Thanks again,
 
I personally don't think that makes a huge difference. What I would do instead is leave a strip of the L2 screen less-cleaned and let the algae propagate downward, and then harvest or clean the area where the algae seems to be preferentially growing clean more often, and then where the algae doesn't seem to like to grow, don't clean that area quite as much. In fact you might try that first - keep knocking back the good growth sections to try to force the growth to fill in the other areas

That said, I keep saying you it's hard to force algae to grow, it's going to grow where it wants to. Your system is kind of weird, I don't understand why the L4 grows well right out of the gate and the L2 is still bare in the middle, it doesn't make a whole lot of sense. So I'm kind of throwing darts here...
 
Floyd R Turbo said:
The issue is that the fixture you have is on a multichip fixture, so the diffuser may not work the way I described it.

I would just give it time, it's difficult to force growth to happen.

My guess is that with that fixture, the LEDs are probably only about 1.25 inches apart - that's way too close. The fixture might be 5.4" wide but that's not the effective spread of the LEDs. So because the LEDs are so close together, they are having an overlapping effect and causing the hot spot. That's a bit more difficult to take care of with a diffuser. It would be better to back the light fixture off so that the light spreads out a bit more, but then you lose a lot of intensity. You could also remove the lenses on at least a few of the LEDs, the target ones being the blue ones and the 630s as those are higher intensity.

What size tank is this on? How much are you feeding?
Click to expand...
120g display, 60g frag tank, and 125g sump. The sump probly has 80-90 gallons in it. I have a kole tang and a sixline wrasse in my frag tank. Purple tang, malenarus wrasse, yellow coris wrasse, melagris wrasse, 2 midnight clowns in the 120 display. Lost my 5 chromis in the display. And feed a cube of pe mysis or equal size piece of larrys reef food. Also feed nori randomly and extra on weekends. Also feed reef roids and reef chili to corals every other night
 
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Thanks mpsteve that helps

So the screen right now is 13x10=130 sq in which by the feeding guideline is over 10 cubes/day. The light being ~12-14W probably, that's more closely matching a screen that is maybe 7x7 or 8x8 at the most, so if you look at it from the perspective of "the light is limiting the screen's capacity" then you have a 4 to 5 cube/day scrubber.

the amount you are feeding is probably (ballpark) in the 3 cube/day range, so ideally the screen should be able to support a bit more feeding - you've got some "breathing room" with your setup.

If you keep increasing feeding and start to push the capacity of the scrubber, all you need to do is switch out one of the lights for larger one with more coverage and you've added a few cubes/day to the overall capacity. Then you can move that fixture to the other side and that would effectively increase it a bit more.

But back to the center fill-in, what you could try is backing the fixture off slightly and extending the "on" time to compensate. This would be similar to dimming. Backing the fixture off will cut the center intensity down and might let that fill in. With the lenses on the fixture, you can probably safely back that off 1" without negatively affecting the growth.

I guess before I say to do that, I should also ask: how far away are those lights now (pic would help too) and how many hours/day do you run them? forgive me if you already answered these...it's been a long week
 
SantaMonica said:
This is classic detachment from dead roots
Click to expand...
That would be true if there was growth there one day, and gone the next. But if I am understanding this correctly there has never really been a lot of growth there.

So "it looks like it could be detachment" might be the better than a definitive answer without gathering all the information to come to that conclusion.

All you have to do is read through this thread and you can see where you frequently jump to conclusions without asking any questions first.

sensei said:
What can be the cause of this detachment?
to much light intensity? to much light time? to much flow?
Click to expand...
Detachment is usually when your light isn't strong enough to reach the base of growth, usually when you let the growth period go too long and it gets very thick, and usually when it's an open-air screen or the growth isn't filling in like 3D growth should.

So detachment is possible, but that would be something you should have been able to notice happening. And I don't think it makes sense given the situation, but it does raise a few questions that need to be asked

How long did you let the screen grow for this particular example?

How consistently have you been seeing the lack of growth in the middle of the screen?

Have you ever pulled out a screen and had full coverage in the center?

Have you checked the screen a regular periods during the growth cycle and noticed that you have growth in the center one day, then on a subsequent day you do not have growth?

When you pull the screen out of the growth chamber, is there significant algae that "sticks" to the growth chamber and pulls off of the screen as you remove it, and does that line up with this area of low growth?

Have you noticed large chunks of algae freely floating around the tank, or lodged onto rock (i.e. algae that is easily removed, indicating that it did not grow on the rock but rather just "deposited" there)?
 
Waterfall detachment is when flow and light no longer can reach the screen, and it dies off, letting go usually in the middle of the screen. The remaining growth has turned yellow or wheat color. Screen should be cleaned before this.
 
jason2459 said:
Just a side note. I hope you don't depend on that check valve... ;)
Click to expand...

No the 125 sump has maybe 80 gallons in it and the 1 inch return is only 15 long so it's not holding 45 gallons. It's there to stop back flow during every feeding but if it fails I'm also good
 
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