Algae Scrubber Basics

[SantaMonica]

velcro adhered to thin plexi

Yea I have not heard yet of anyone staying with velcro. Might be the lack of flow-through.

 

[Deep Reef]

I have a couple of quick questions I'm hoping someone can answer.

1st I currently have a 40g breeder as my sump. From left to right water drops into the left compartment where my skimmer is, then bubble trap then pump section. from pump section it is pumped into the taller right hand section where my chaeto is located. If I use a dedicated pump for the ATS can I install it into the right section which has the slower flow or will this not work properly?

2nd, is it possible to use screw LED bulbs and not replace them as often as the CFL or even at all?

 

[cubfanmatt]

LiMaZoo,
My problem was a wavy screen. Got to hard core with it when I roughed it up.

I got a new screen and scaled back on how rough I got with it. I later ran it in tap water, without any direct light, for three day and got a light brown algae in the roughed up area of the screen. I though that was a nice indication that the screen was roughed up enough.

 

[SantaMonica]

Scrubbers can go anywhere in a sump and function the same. I've not seen a lot of difference.

Yes the screw LED bulbs will last a long time. Trouble is to no be over-focused.

 

[Deep Reef]

Thanks for the comments. I should have read a little more as I found Floyd's reference to the revised basics.

thanks again, totally new to this idea....and learning

 

[biglurr54]

I need help with building an algae scrubber! Please Help.

I am building a 16 gallon tank for my desk at work. It will be replacing my 7 gallon that is there now. It is going to have a sump and no equipment in the tank.

The filtering will be done with an Algae Turf Scrubber. I would like to run this off the overflow. I am going to be running two 3/4 pvc elbows as overflows. They will have a screen over them to keep out tank residence. The return pump will also be the circulation pump. It is a quietone 2200 running a SCWD. the calculated flow rate to the tank is 425 GPH. I will be doing biweekly water changes of 1 gallon.

I need help designing the scrubber.
1. Should I have one overflow feed a scrubber and the other one just dump into the sump?
2. Should I have both overflows feed the scrubber? Would 425 GPH be too much for a small scrubber?
3. How big should my screen be? The tank will eventually be stocked fairly heavily and will have SPS so water quality is a must.
4. What lights should I use? I will be going spiral compacts but I feel like 23 watts on each side might be too much light and burn the algae.

 

[Floyd R Turbo]

1. Should I have one overflow feed a scrubber and the other one just dump into the sump?

If you do a direct overflow feed, I would recommend having a backup configuration of some type. In the case where you have 2 overflows, if one of them is capable of handling 100% of the flow, then use one overflow for the scrubber and the other dump. This protects the tank from overflow in the instance where something manages to bypass your strainer protection, gets down to the screen/slot pipe, and clogs it.

If one pipe cannot handle the flow, then you need some sort of bypass protection. This would be a second pipe that would tap off of a low point on the scrubber feed pipe, then go up to a level a little below the tank water line, then to an open T and down to the sump. This way if you get a significant clog, you have a path that bypasses the scrubber without removing the water column pressure that you need on the slot/screen junction

2. Should I have both overflows feed the scrubber? Would 425 GPH be too much for a small scrubber?

425 is not too much depending on the width. if the scrubber was about 12" wide, that would be about right for the 'normal' flow rate of 35 GPH/in. If you reduced it to 8.5", then you're at 50 GPH/in Either way, that's a huge scrubber for a 16 gallon tank.

3. How big should my screen be? The tank will eventually be stocked fairly heavily and will have SPS so water quality is a must.

Based on feeding, roughly. I would be surprised if you could feed a 16 gallon tank 1 cube of food per day and not have major long term issues. so you're looking at a pretty small scrubber, like 4" x 4".

4. What lights should I use? I will be going spiral compacts but I feel like 23 watts on each side might be too much light and burn the algae.

CFLs are fine, you can get them in 13W which would be good with one on each side of a 4x4 screen.

Very small setups like this that are not heavily fed might be served better by other methods though. This is where the UAS type scrubbers start to make a bit more sense, because that concept was really designed around the nano tank idea initially. Then you don't have to worry about overflow feeding and protection.

 

[biglurr54]

The tank is going to have a sump regardless of the algae scrubber. I like the ides of the waterfall algae scrubber over the upflow method. I was thinking about going with a 4x6 inch screen and leave 1/2 inch in the water so there would be 4x5 inches of screen to grow on. I will plumb one overflow to the scrubber and the other will dump into the sump. That will give me about 53 gph per inch over the screen. Is that too much? Should I throttle it down?

Is there any benefit to containing the scrubber in a box with an open bottom? Im guessing it would need to breath fresh air right?

Im thinking of building a 6x6x10 acrylic box with out a bottom and covering the box in plastic mirror so the light cant escape. It will be more efficient with the lights and it will keep the spray down. Is this a good or bad idea?

 

[Floyd R Turbo]

The tank is going to have a sump regardless of the algae scrubber. I like the ides of the waterfall algae scrubber over the upflow method. I was thinking about going with a 4x6 inch screen and leave 1/2 inch in the water so there would be 4x5 inches of screen to grow on. I will plumb one overflow to the scrubber and the other will dump into the sump. That will give me about 53 gph per inch over the screen. Is that too much? Should I throttle it down?

Might be a bit much at first, but once the screen matures that flow will work. I don't know how you would throttle it back unless you throttled back the return pump. Is that flow rate calculated or is it actually measured?

Is there any benefit to containing the scrubber in a box with an open bottom? Im guessing it would need to breath fresh air right?

There's not really a need to 'breathe' necessarily. I run fully enclosed scrubbers. Some run open-air, some put fans on them (for cooling and also oxygenation sometimes).

The main benefit is protection from spray and salt creep

Im thinking of building a 6x6x10 acrylic box with out a bottom and covering the box in plastic mirror so the light cant escape. It will be more efficient with the lights and it will keep the spray down. Is this a good or bad idea?

Light escape can be taken care of with reflectors on your CFL lamps (which you need anyways to direct the light forward) or by using LEDs (which are directional in nature). Using mirrored acrylic will get you a little extra benefit, but likely it's more trouble than it's worth - you can more easily increase wattage.

 

[gregrocks79]

Here's my DIY. I sanded down the mesh to a very rough surface. Also intertwined some barbed mesh that I cut out and glued in. Magnets to hold it and well see how it goes.

What's the best lighting everyone has experienced?

 

[biglurr54]

Well after more and more research I think I have a plan. Im going with a waterfall style scrubber in an acrylic box with a throttled overflow feeding it. This will allow me to adjust the amount of flow depending on growth. it will allow me to adjust the flow per inch from 0 to 50 gph. The lighting will be 4 660 deep red LEDS running at 350ma. 2 on each side with a light diffuser

Should I bump the lighting up to 700ma?
Is 4 Reds enough or should I add more?
Should I add a blue to the LEDS?

 

[Floyd R Turbo]

For LED, one per 8 sq in per side... For high-intensity, double that.

If running the LEDs at half-power (which is essentially what I recommend during start-up) then I would run more of them, but it depends on the size of the screen. If you are still talking a 4" wide x 5" tall screen (effective area) then 2 per side would be the minimum (one per side of each 8 sq in) running a 700mA. What would be better is to do 4 on each side at half power, with the ability to run them at full power just by switching the wiring around a bit. Essentially you could run both arrays off the same driver, and wire them in parallel. When you wanted to double intensity (after you get a base of growth) then switch 2 lead and they are in series (full intensity)

On the blues, you want these to be at half power all the time. If wiring is too tricky to make this happen (you can wire 2 LEDs in parallel within a series, but you don't want 2 blues on each side of this screen - only one) then make the blue a 1W LED and then you can wire it directly in series with the rest of the blues.

 

[GOSKN5]

I have been running my ATS for about 3 months now and really having a hard time getting green growth... I got brown slime for a long while... recently it has changed to long brown strains..

Tank is a 57 gallon 20g sump
Feed lightly once daily
23w CFLone side only
screen is around 5"x10"

Tank doesn't have much algae.. few spots here and there but I want to keep it that way...

Need more light? More flow?

 

[Floyd R Turbo]

Quoting to fix the photos...

I have been running my ATS for about 3 months now and really having a hard time getting green growth... I got brown slime for a long while... recently it has changed to long brown strains..

Tank is a 57 gallon 20g sump
Feed lightly once daily
23w CFLone side only
screen is around 5"x10"

Tank doesn't have much algae.. few spots here and there but I want to keep it that way...

Need more light? More flow?

 

[Floyd R Turbo]

Now that I've looked at the pics, I can see one major thing: Your tank looks great. That is your end goal, not necessarily to grow one type of algae or another. So don't lose that focus.

Now on to your scrubber, a few potential things:

1) screen size is 5x10 = 50 sq in but single sided, which cuts effectiveness in half so it's really more like a 2 cube/day scrubber. feeding "lightly" is a relative term, any idea on how many cubes/day you feed, roughly? I'm guessing 1 or less probably.

2) DIY reflector looks good - probalby could be more curved around the back of the lamp vs square, but I don't think that's the issue. How many hours/day is the CFL on?

3) Flow, do you know how much you have? Should be around 180-200 GPH for a 5" wide screen, or more. More flow might deliver more nutrients. However if you don't have a nutrient issue, this won't matter much. Which leads into next question

4) what do N and P measure?

 

[GOSKN5]

Now that I've looked at the pics, I can see one major thing: Your tank looks great. That is your end goal, not necessarily to grow one type of algae or another. So don't lose that focus.

Now on to your scrubber, a few potential things:

1) screen size is 5x10 = 50 sq in but single sided, which cuts effectiveness in half so it's really more like a 2 cube/day scrubber. feeding "lightly" is a relative term, any idea on how many cubes/day you feed, roughly? I'm guessing 1 or less probably.

2) DIY reflector looks good - probalby could be more curved around the back of the lamp vs square, but I don't think that's the issue. How many hours/day is the CFL on?

3) Flow, do you know how much you have? Should be around 180-200 GPH for a 5" wide screen, or more. More flow might deliver more nutrients. However if you don't have a nutrient issue, this won't matter much. Which leads into next question

4) what do N and P measure?

Thanks for the help... feed very lightly.. NLS pellets 4 days a week 1/2 cube of frozen 3 days a week.. once per day..

CFL is on 18 hours

Don't know the flow, but can increase it if needed.. its a maxijet 600 buy dialed down with a ball valve...

I have never tested phos before... haven't tested nitrates in a while but can.. need to get a Hanna for phosphate I guess...

Should I consider more wattage or more flow?

 

[Floyd R Turbo]

Ooh, that's your issue right there. The MJ600 unvalved would come up short. I have tested the flow on the MJ1200 on a 6" wide screen and even that comes up way short. I guarantee you are low flow. MJs / Cobalts do not have very good head loss charachteristics, at all.

For that width of screen I would recommend a Rio 1100 dialed back a bit. A Rio 1100 on a 6" wide screen at 12" above the water level results in an actual flow on a brand new screen of about 240 GPH. for 5" x 35 gph/in = 175 GPH is where you want to be, or more. Since your screen has growth, I would consider it mature enough to handle that much flow (240 GPH).

But you may want a slightly smaller pump than that Rio 1100, because you might get some spray. Cover the slot/screen junction in saran wrap or a black plastic garbage bag section to protect the CFL (and keep the water where it belongs!!).

Bottom line though is that MJs/Cobalts are good for mixing salt and media reactors and not much else - especially scrubbers.

 

[GOSKN5]

OK great... I'm gonna open it wide for now and then try to replace with a better pump as soon as I can... thanks for the help!!

 

[GOSKN5]

OK so I increased the flow and it seems like its coming out everywhere... I am a little worried it will squirt out of sump... do I need to make the slit bigger maybe?

 

[SantaMonica]

Slots tend to fill-in after the growth starts, but you can lay a sheet of plastic wrap over it.