Algae Scrubber Basics

[Floyd R Turbo]

Hey guys, is there a preference for the count # for the plastic canvas used for a scrubber? Should I be going with a 7 count, 10 count or 14 count? Also, if you could, why is one better than the other if at all?

thanks.

count = holes per inch

5 count - big holes - not enough surface area
7 count - perfect size, screen thickness is perfect, roughs up well
10 count - holes very small, which is fine, but thinner material does not allow you to rough it up well before it rips
14 count - never seen it. See above, but probably worse

Of course I have another forms of filtration. In fact, I wasn't going to get any ATS when I designed the aquarium. I ordered a 200 gallon refugium, for having multiple algae to control N and P. But ATS is more effective, IMO.

I have a Bubble King 650 external skimmer (rated for +2000 gallons), ozone generator (a few mg/h, just for water clarity) plus the ATS.
And the display tank is going to be BB, with high flow (+73 turnover rate) to make sure any waste will be collected out of the system.

Which brand of leds would you recommend? Here in Spain leds have just began to show up and I would prefer to order them from U.S

Thanks!!

Spot on man.

I would find a way to feed the outflow from the skimmer to the scrubber if you can, or if the skimmer dumps into the sump somewhere, and you pump-feed the scrubber, put the pump right there in the same chamber. The aerated water is good for scrubber growth (has been shown to reduce/eliminates the algae scrubber's tendency to uptake bicarbonate (alk) when CO2 is gone, and promotes green growth)

As far as LEDs go - you do get what you pay for, IMO. I would go with Philips Luxeon ES 660nm Deep Reds and 440-450nm Royal Blues. I get them from Steve's LED because he tells you exactly what bin you are getting and since he is a distributor for Philips, you get them at the best price. They are consistently the same spectrum, high output, high quality.

 

[crazzyreefer]

Garfield, you will also have to adjust the size of your screens for water volume over the screen. I set up a lot of big tanks, Filtering and lighting don't scale exponentially.

 

[Floyd R Turbo]

crazzyreefer - good point. this is one that i have been making recently as well. While the feeding based guideline is great for scaling the screen to the amount of input (feeding), it does not account for the "turnover rate" across this screen.

An extreme example can make my point. Let's say you have a 400 gallon system, and you feed 10 cubes/day. That's a 120 sq in screen. If you make that screen 6" wide and 20" tall, then you get 35 GPH x 6 = 210 GPH across that screen, giving you a turnover rate of 0.5/hour. That's pretty low. Conversely, if you made the screen 20" wide and 6" tall, that's 35 x 20 = 700, and you have almost 2/hr turnover.

Back in the "volume based" sizing days, a 100g system might have a 20x5 or 16x6 screen, so 500-700 GPH flow rates were not unheard of. This is 5 to 7 turns/hour!! I think this factor is overlooked now. However, with a smaller screen that concentrates the growth down and forces the growth to grow outwards (toward the light source), GHA gets preferential growth (Santa Monica reminded me of this today on another forum). You can also increase the flow rate per inch to offset this effect (I know some who put 400+ GPH over a 6" wide screen and get mad growth).

So Garfield, if you have a 1300 Gallon system, I would say you would really (eventually) want to shoot for 1x turnover rate at a minimum. You are running multiple filtration so I would think you should not really need to exceed this.

With a 24 x 20 screen, 24" wide, x 35 GPH = 840 GPH. So you're not quite there, but I think that's OK. I think that when you get to a screen that is that large, there are other factors that apply. Not that I can say that I know what those other factors are (I can admit here that I am extending my knowledge to what makes sense) but it seems that you would think one would start to reach a point of diminishing returns. That is, Once a screen is very large, you may be able to change one factor such as overall total flow rate or lighting intensity or photoperiod and have a more significant effect than you would with a smaller screen.

For instance, on a 6x6 screen with high-level LED lights, if you increased the photoperiod from 9 hours to 12, you might increase the capacity by 33% from 3 cubes/day to 4. But on your screen, would a similar increase cause the capacity to go from 40 cubes/day to 53? Maybe, but it could be more, and it could be less. Many factors depend on the specifics of the system.

Well anyways this is a long post. The point is to get it close and you should be fine.

 

[larson77]

Hi everyone, I have been reading the majority of this thread, very informative! I am planning to order a skimmer from a website called reefshops.com and happened to come across this:
This ATS
If I were to rough up the surface quite a bit, do you think this would be a viable option?
It's cheap as dirt and I already am paying the high shipping from China.

 

[larson77]

Hi everyone, I have been reading the majority of this thread, very informative! I am planning to order a skimmer from a website called reefshops.com and happened to come across this:
This ATS
If I were to rough up the surface quite a bit, do you think this would be a viable option?
It's cheap as dirt and I already am paying the high shipping from China.

 

[JohnnyB in SD]

I think someone else posted about those some months ago. Has no lighting. Pretty small, limited filtration ability. For less than $30 you can build something far better. Depends on what space you have to accommodate one and how much filtering capacity you need or want.
For my situation and from what I know about ATS, I would not waste my time with it even if it were free.

 

[srusso]

i think someone else posted about those some months ago. Has no lighting. Pretty small, limited filtration ability. For less than $30 you can build something far better. Depends on what space you have to accommodate one and how much filtering capacity you need or want.
For my situation and from what i know about ats, i would not waste my time with it even if it were free.

+1

 

[symon_say]

My new scrubber almost 2 weeks, should i clean it or wait a little bit longer??

 

[SantaMonica]

Looks like more light it hitting the top?

 

[Floyd R Turbo]

Rinse in tap water (room temp), rub gently with fingertips only, clean the slot pipe.

 

[symon_say]

Looks like more light it hitting the top?

Yes, for know it have only 1 bulb until i build the led fixture.

 

[pat02026]

Here is a few pics of my scrubber. I have still yet to get it running, but if all goes well, this weekend will be the green light. the screen size is 4x6" and it is lit by 7 660nm & 2 420 nm 3 watt led's per side. The enclosure is painted black to keep light inside. hopefully it works, having 7 fish in a 54 gallon display (over 120 gallons total) is pushing it for a reef tank!! any suggestions on lighting? I was planning on 14 on 10 off, I am running my lights at about 50% power to start (through the meanwell driver)

 

[nanomania]

kool scrubber....... keep us updated......

 

[nanomania]

crazzyreefer - good point. this is one that i have been making recently as well. While the feeding based guideline is great for scaling the screen to the amount of input (feeding), it does not account for the "turnover rate" across this screen.

An extreme example can make my point. Let's say you have a 400 gallon system, and you feed 10 cubes/day. That's a 120 sq in screen. If you make that screen 6" wide and 20" tall, then you get 35 GPH x 6 = 210 GPH across that screen, giving you a turnover rate of 0.5/hour. That's pretty low. Conversely, if you made the screen 20" wide and 6" tall, that's 35 x 20 = 700, and you have almost 2/hr turnover.

Back in the "volume based" sizing days, a 100g system might have a 20x5 or 16x6 screen, so 500-700 GPH flow rates were not unheard of. This is 5 to 7 turns/hour!! I think this factor is overlooked now. However, with a smaller screen that concentrates the growth down and forces the growth to grow outwards (toward the light source), GHA gets preferential growth (Santa Monica reminded me of this today on another forum). You can also increase the flow rate per inch to offset this effect (I know some who put 400+ GPH over a 6" wide screen and get mad growth).

So Garfield, if you have a 1300 Gallon system, I would say you would really (eventually) want to shoot for 1x turnover rate at a minimum. You are running multiple filtration so I would think you should not really need to exceed this.

With a 24 x 20 screen, 24" wide, x 35 GPH = 840 GPH. So you're not quite there, but I think that's OK. I think that when you get to a screen that is that large, there are other factors that apply. Not that I can say that I know what those other factors are (I can admit here that I am extending my knowledge to what makes sense) but it seems that you would think one would start to reach a point of diminishing returns. That is, Once a screen is very large, you may be able to change one factor such as overall total flow rate or lighting intensity or photoperiod and have a more significant effect than you would with a smaller screen.

For instance, on a 6x6 screen with high-level LED lights, if you increased the photoperiod from 9 hours to 12, you might increase the capacity by 33% from 3 cubes/day to 4. But on your screen, would a similar increase cause the capacity to go from 40 cubes/day to 53? Maybe, but it could be more, and it could be less. Many factors depend on the specifics of the system.

Well anyways this is a long post. The point is to get it close and you should be fine.

A few Qs...

1) Is an external scrubber a better option or is straight from overflow better?

2) if straight from overflow, is 2" diam. pipe ok as thts what i prefer?

3)what should be the pump size for return line if using external scrubber?

 

[SantaMonica]

Not being a plumbing person, I'll just answer #1...

The physical location of a scrubber is not important. But everything else is: Flow, lights, roughness, ease-of-cleaning, etc.

 

[JohnnyB in SD]

Nanoman-
For me, feeding the screen from an overflow is preferred because you're not adding another 24/7 pump to the electrical consumption bill. But if the overflow does not provide adequate 35gph / inch flow, then it is necessary to use a pump for the ATS to function properly.
2" pipe has less pressure loss than smaller pipes, so I would say plumb with it as far as you can. I personally use 1.5" from the siphon drain until I get to the 1" slot pipe.

 

[Floyd R Turbo]

A few Qs...

1) Is an external scrubber a better option or is straight from overflow better?

It does not matter where you place the scrubber

2) if straight from overflow, is 2" diam. pipe ok as thts what i prefer?

2" overflow I'm guessing is made for a lot of flow? How much flow do you have coming from the tank via this 2" pipe?

3)what should be the pump size for return line if using external scrubber?

Pump needs to be sized such that it can supply the necessary 35 GPH per inch of screen with when head loss and resistance from the slot over time is factored in. The head loss is easy - I figure that the slot pipe equates to about 2 feet of loss, and then just add the vertical to that. So if you had 12" from the centerline of the slot pipe to the operating water level in the sump (NOT to the position of the pump underwater), this is 3 feet of loss. Choose a pump that matches your required flow rate at this head loss +100 GPH. So if you have a 6" slot, you need ~210 GPH. Find a pump that supplies 300 GPH at your head loss. You can always valve a pump back, but you can't increase flow.

 

[nanomania]

It does not matter where you place the scrubber



2" overflow I'm guessing is made for a lot of flow? How much flow do you have coming from the tank via this 2" pipe?



Pump needs to be sized such that it can supply the necessary 35 GPH per inch of screen with when head loss and resistance from the slot over time is factored in. The head loss is easy - I figure that the slot pipe equates to about 2 feet of loss, and then just add the vertical to that. So if you had 12" from the centerline of the slot pipe to the operating water level in the sump (NOT to the position of the pump underwater), this is 3 feet of loss. Choose a pump that matches your required flow rate at this head loss +100 GPH. So if you have a 6" slot, you need ~210 GPH. Find a pump that supplies 300 GPH at your head loss. You can always valve a pump back, but you can't increase flow.

2) 2" pipe coz if the snail goes in overflow, it wont block my overflow......

3) i was asking about the return pump from sump to dt (currently i guess mine is 10 times flow) not the scrubber pump.

external scrubber i ment was the acrylic scrubber that many have been sold which u can jus attach to the system...

 

[elviraveloz]

Floyd I'm trying to build one too. I'm not good with math so, can you please help me? I'm feeding four cubes frozen food, one noni sheet and a teaspoon pellets a day. 220g tank. Two sump connected one higher than the other, one has refugium with overflow(sock as filter) and 250g protein skimmer or first section of sump, second sump has second overflow with filter sock, here is where I'm planning to build algae scrubber. I have two external pumps. The total GPA overflow on sump is 390. What size screen have to be?

 

[Floyd R Turbo]

external scrubber i ment was the acrylic scrubber that many have been sold which u can jus attach to the system...

Well one really doesn't have anything to do with the other if your return pump supplies way too much flow for the scrubber, wouldn't you just run the scrubber on a dedicated pump? Of maybe a tap off the return line?

Floyd I'm trying to build one too. I'm not good with math so, can you please help me? I'm feeding four cubes frozen food, one noni sheet and a teaspoon pellets a day. 220g tank. Two sump connected one higher than the other, one has refugium with overflow(sock as filter) and 250g protein skimmer or first section of sump, second sump has second overflow with filter sock, here is where I'm planning to build algae scrubber. I have two external pumps. The total GPA overflow on sump is 390. What size screen have to be?

The only thing to concern yourself with is the feeding rate. I haven't looked up the calcs (look at the posts in my footer/signature) but off hand it sounds like 6 cubes/day, but you have a 'fuge and skimmer so you might get away with less, but the 'fuge will get out-competed eventually

The way you have your sumps setup, you can't take from the overflow of sump1 to sump2 because you have no head pressure on the slot pipe (assuming you are doing waterfall?) Maybe a UAS in the 2nd sump.