Mega-Powerful Nitrate and Phosphate Remover Replaces Skimmer, Refugium, part 1-4

[SantaMonica]

What is a boundary layer, and why is it important? It the layer of water that is microscopically close to the algae; the water molecules that actually touch the algae:

This boundary layer area of the water has zero flow, because it has to have the same flow as the algae, which of course is zero. Since there is no flow (velocity) here, nutrient transport through it is slow. The faster the water flow, the smaller the boundary layer, and the faster the nutrients can get to/from the algae from the water.

One point to clarify about nutrient exchange: Contact with air is not needed. Scrubbers operate the same whether they are sealed or open (except for cooling/evap), because the exchange is not with the air; it's with the water. The reason algae grows better in an overflow, or where water hits a scrubber screen, or where waves hit the beach, is because the flow is higher here and thus the water's boundary layer is thinner, which allows for better nutrient transfer between the algae and the water. This is what a vertical waterfall scrubber tries to achieve: Fast flow from top to bottom. Further info can be found here:

Seagrasses: Biology, Ecology, and Conservation, p 199, by AWD Larkum, Robert Joseph Orth, Carlos M. Duarte:

"As water flows through seagrass [or algae] beds, a boundary layer develops on the sediment surface, as well as on each seagrass [and algae] component exposed to the moving water. The faster the water moves, the thinner the diffusive boundary layer (DBL) becomes, and consequently, the faster the transfer of molecules from the water column to the sediment and/or seagrass [or algae]. It follows then that when currents [flow] are weak, the flux of molecules to the seagrass [or algae] surface may be limited by diffusion through the [boundary layer] (i.e., physical limitation). Under those conditions, many biological sites or enzymes in the seagrass [or algae] tissue are available to assimilate molecules when/if [!] they reach the plant's [or algal] surface.

 

[SantaMonica]

Several Updates:

1. Change CFL or T5 bulbs every THREE MONTHS!

2. Wattage recommendation: 0.5 Watts per gallon for medium filtering. 1.0 for high filtering.

3. CFL bulbs: 55W is the max that works good. If you need more watts, get two or three smaller ones, or go to T5HO (best)

4. Skimmer overflow: Be careful of your skimmer overflowing (if it does not have an overflow tube.) The rotting food in the skimmer cups has been growing bacteria, and thus producing ammonia, so if it overflows into your sump, the ammonia can kill things. If this happens, then a scrubber removes this ammonia from the water (skimmers do not remove ammonia; they only make ammonia in the cup.)

5. Current best place to get plastic canvas: www.EverythingPlasticCanvas.com

6. Surges are not recommended for scrubbers, because (1) the have not shown to improve operations, (2) they are hard to diy, (2) they are noisy/messy, and (4) they reduce the filtering contact time with the water.

7. Cleaning: If your screen goes up into the pipe, you can clean the screen extra good in that area, so that less algae will grow up into the pipe.

8. Purple growth: If your screen is new, and you are getting thin purple growth in spots, it is probably cyano because of weak lighting. If your screen is 3 months old or more, and you start getting purple growth, feel it. If it's is furry, then it's turf. If it's not furry, then it cyano.

9. Never run the lighting 24/7.

10. Cyano in display: Sometimes, after an algae scrubber has removed most of the nuisance algae in a tank, cyano will grow a bit more. This is normal, because cyano does not eat the same thing that nuisance algae does (thus, the cyano now has less competition). But the cyano will reduce too eventually. The cyano occurs because it has the capability of getting nitrogen directly from the water, without needing Nitrate, Nitrate or Ammonia/Ammonium (which is what algae gets nitrogen from). But as the scrubber continues to filter, the cyano will have a harder and harder time holding on.

11. Why "polished" water is bad: The "clean" water look you get with a skimmer and other mechanical filters is because the food (i.e, waste "protein") has been removed from the water. This is what you want if you have just large fish. But if you want a "real" natural reef, you don't want to do this. Go diving some time and look at the water on a natural reef; there are millions of specks and dots and particles and things floating in the water in a super thick soup. And that's just six inches in front of your face. These things are what feed everything, including small fish.

 

[SantaMonica]

Success Updates:

Jason1 on the RS site: "I have to tell you, this thing works great. My tank is definitely showing signs of improvement and looks really cleaned up from what it used to. Thank you."

Danno.Thomas on the SWF site: "Have mine up and functional on a 30 gal, that was just changed over from a 20 gal, had zero new algae growth in the DT. Scrubber is working like magic. Small feather dusters abundant. 6 years in the hobby and my tank has never looked more alive. This is my exclusive filtration."

Troythegreat on the 3R site: "i personally think that scrubbers are a Godsend to reefers. IMO scrubbers work much better than skimmers at 1/10th the cost, all you need is a little discipline. I've had my scrubber running on my 75gal for about 7 months without any trace of nitrates or phosphates. I have 2 clowns, 4 damsels and a engineer goby plus many coral. i feed my coral once a day and my fish twice a day.........i clean the scrubber every 5 days and change carbon once a month."

Chadjwil on the scrubber site: "I've been running an algae scrubber on my 55 [for 7 months]. That tank has never had a skimmer or canister or any other filtration in it, ATS since birth! I'm totally loving it, and...due to space restrictions in the stand ... my screen is undersized, and until last week it was under-lit (bare minimum now), and it's still keeping that tank clean and nutrient free. My fish are so healthy looking, more so than all but the best of the LFS within 50 miles, and my shrimpies molt like mad. I used to be a little leary about telling people that I ran an ATS because of all the sideways looks and comments that I got (and I'm sure my wife thought I was crazy too), but over the last few months more and more people have been commenting on how nice our tank looks, and that theirs was full of algae and a pain to clean all the time, we must spend all our time cleaning and screwing with it...now I get a lot of satisfaction telling them that I spend 5 minutes scraping algae off a plastic tank divider every week or so and I'm done. True believer here."

 

[SantaMonica]

Update: Deep-Sump Nano's

There are two types of nano's: The one that has a hatch on the top, so you don't have to open the whole lid to get to the filters, and the one without a hatch, where you do have to open the lid. It's this second one (with a deep "sump"), that is the most difficult to put a scrubber into. Indeed, if at all possible, you want to instead make an external scrubber, that sits above the tank:

You can enclose the scrubber with a box, or just use the lid of the bucket, to keep the light in. And actually, since nano's need such small screens, you could just use a coffee can, with the lid, which will block out all light once sealed. Decorate the can like a vase, and it will add to your decor. And use black tubing too so it looks nice. It doesn't need air flow, unless you want evaporation and cooling. Regardless, if you do this design, make sure to use "aquarium-safe" silicon on all electrical connection inside the bucket (including where the bulb screws in), because water and salt will build and short it out.

If, however, there is no possible way to put a scrubber above your nano, then you can install one in the "sump" area if you are good at DIY. It's a tight fit, but it can be done:


Riaanp on the MASA site did this:

And Nitschke65 on the SWF site did this:

The idea is to use one of the compartments (probably the middle one) for a waterfall area. For lighting, although Riaanp put the light inside, it's probably best to put the light on the outside (back) of the tank, and scrub off the paint on the backside so that the light can get through to the scrubber screen. The bulb only needs to be one watt for every gallon, so a 13 or 18 watts CFL 3000K is fine.

Fortunately you don't need much screen size for a nano... just 2 square inches (6.25 square cm) for every U.S. gallon (3.8 liters), because the screen is one-sided.

This type of setup is nice because it does not require any cutting of the sump walls, and thus can be converted back easily. Also, there is no real cost... just the screen (2 layers of roughed-up plastic canvas, about $1 USD), and the bulb and socket, probably $7.

 

[Miss my puffer]

SantaMonica, I have been reading up on turf scrubbers and have decided to try and make one. I got a tray that is 12in wide x 24in long x 2in. high. The main tank is a 120 gal and the sump is a 55 gal. I was planning on having my overflow come down onto the scrubber. My question is what would be the best way to drain the water onto the screens (the overflow is 1 1/2in and I was thinking of slicing the pipe so it drains across the whole screen, but am wondering if I would be able to keep up with the 900 gal hr the pump pushs, probably only 600gal/hr after head loss). It is going to have three 3/4in drains, which I think would be more than enough to drain the scrubber. I haven't figured out the light yet but may be two spotlights or 65w pcs. Is there any major flaws or hints you can give me on my idea for the setup so far. I have also included a pic of the tray. Thanks.

 

[SantaMonica]

Main thing about horizontal is to get the flow as fast as possible. Scrubbers need fast, thin flow. So you don't want any water standing on top of the screen... needs to drain as soon as it's in the try. Also, horizontals are one-sided, and thus need to be twice as big, which yours is.

I would slant the tray as much as possible so water flows fast. Then I'd feed it at the top with a pipe with many 1/2 inch holes.

130W pc light (3000K) is good.

 

[Miss my puffer]

Thanks for the reply. I like the idea of lots of 1/2in holes over the cutting the side out of the pipe. Would the 130w of pc be alot better than adding 2 spotlights? I would perfer to go with the spotlights, but if the pcs give me a better chance of succeeding and being happy with it then that is what I will do.

 

[SantaMonica]

Spots are fine. 2 X 45W.

 

[chefjamesscott]

interesting thread

I am running 2 sw and 1 brackish about to set up a 168g tall sw drilled tank I might try this out

will see what happens

 

[SantaMonica]

Updates/Reminders:

Nano scrubbers: In my last update, I said a coffee can would make a good nano scrubber. I meant a plastic coffee can.

Wattage: Your goal should be to get at least 0.5 watts of CFL (compact flourescent light) for each gallon of water, for medium filtering. For high filtering, get 1.0 watts per gallon. And don't use incadescent bulbs... they are much too hot and use too much power. The biggest CFL bulbs you should use should be 45W. If you need more, use extra bulbs, not a bigger bulb.

Be sure not to run bulbs 24 hours.

Be careful of overflowing skimmers; there is a lot of ammonia in that skimmate. A scrubber will help eat that ammonia if it overflows.

If you have cyano on your screen, you need more flow and/or more light.

If you smell any kind of "algae" smell while the scrubber is running, you need more flow.

If your tank has gotten rid of the nuisance algae, but cyano seems to be increasing, this is normal. Cyano does not eat nitrate and phosphate like algae does, so after your scrubber has starved the nuisance algae, the cyano has more room to grow. But if you keep your scrubber running strong and proper, the cyano will fade too.

If you have rubbery green algae, it means the flow is getting cut off and the algae is baking.

The best current spectrum for the bulb is 3000K (550 nm). This is yellowish-greenish, and it fits right in the middle of the red and the blue peaks of photosynthesis:

Pipe: Slots deliver much more water than drilled holes. Keep this in mind when figuring out how much flow you need.

Sump growth: Some people have open bulbs which light up the sump, and they are growing algae there. You don't want this to happen, so you need to use reflectors, or even foil, to block the light.

Coralline: Since phosphate will slow down coralline growth, you will start seeing more coralline as your phosphate drops in your water.

Advanced DIY trick: For those who can build such a thing, if you could build a top-off device which would shut off the flow to the screen, and then run your FW top-off water on it, then switch back to the regular flow, you would be able to extend the time between cleanings because the pods would be kept in control.

Dead fish: Scrubbers handle dead fish wonderfully; since ammonia is algae's favorite food, when a fish dies the algae will consume as much of the ammonia as it can, which could save your tank if the fish dies overnight. A skimmer, however, does not remove ammonia at all.

What equipment comes first: With regard to scrubbers, here are a few points to consider when planning which device should come before which other device (if you use them):

Skimmer: It should come before the scrubber and after the display, so that it does not remove the pods that come from the scrubber (if you need pods).

UV: Also should come before the scrubber and after the display, for same reason.

Mechanical filters/socks: Same as UV and skimmer. These trap food and pods (which rot and add Nitrate and Phosphate to the water), and thus should be the first thing you should stop using unless you change/clean them daily (but then you are removing the food for the corals.)

PO4/N03 removers: Really doesn't matter because N and P are the same throughout the system.

Fuge LR/LS/Macro: Doesn't matter, as far as nutrient removal is concerned.

Bio Balls (!): Should be removed slowly, unless you have massive amounts of fish, and little rock/sand.

Screens: I will be selling ready-to-use screens soon. But until then, it's best to use two layers of extremely-rough plastic canvas, using a hole-saw (and about an hour) to rough up all four sides of the two sheets:

To demonstrate how rough the screen should be, here is a video of a towel dropped on a rough screen:
http://www.radio-media.com/fish/CanvasTowellDrop1.mpg

...compared to a smooth screen:
http://www.radio-media.com/fish/CanvasTowellDrop2.mpg