My first scrubber!

[steve]

Hi everyone,

Great site, been reading about the scrubbers for over a week now and am very interested in going down this route to solve my nitrate/hair algae on rock issue using natural means.

I'll start with a bit of background.

Tank is a 5 x 2 x 2 with approx 55kg rock, sump with chaeto in 24/7 lit fuge. In addition I'm running carbon, skimmer and fluidised rowaphos. I like my fish so am in to the very well stocked side of things. I've always struggled with cyno in the 3.5 years of the tank being in existence and whilst the cyno went 6 months ago, this was replaced by hair algae and lots of it. So much so I've removed all corals except my nem and some hair mushrooms. I started experinmenting with vodka and sulfur reactor but to no satsifactory results which leads me to this site!



2 weeks ago I did think I'd got my nitrates just about under control as these were reading 10. So I began a process of removing all the hair algae on the rocks (lights out and physical removal) as well as increasing the flow from powerheads (now 12000lph and 6000 lph in addition to reef flsuh system of theoretical 6000lph). This worked at a treat at removing the hair algae, unfortuntately what I didnt relasise was I hadnt solved the underlying nitrate problem and within a week nitrates were at >25. At this point, panic, increase light periods, cut back on feeding to get the algae to grow back on the rocks again!!!

So here I am. Since I'm not a great DIYer, I started to prep my tank to take a scrubber as well as build my first one knowing full well it will need modification to get it where it should be. So last week was spent getting the sump unit ready to take a scrubber and yesterday was adding all the fixings and the scrubber itself.

Current tank stats:

Tank size: 5 x 2 x 2 with approx 55kg of rock. Estimated display capacity including rock displacement 450 litres
Sump size 3 x 1.5 x 1.5 holding approx 100 litres
Total system size c. 550 litres

Nitrates currently at 25 (salifert)
Phosphates registering very slight tinge of blue on salifert ie just above 0.00

Feeding regime: large pinch of flake in the morning along with approx 15 pellets. In the evening 1 cube of frozen mysis supplemented with a couple of small pieces of prawn or mussell and approx 2" square of seaweed sheet.

Current scrubber:

Width (36cm) x length (30cm) using 7 count roughed up plastic canvas
Lit on both sides with 20W spiral CFL (ie 2 light in total) with home made reflectors.
Pump is rated at 1000lph but at the required head height I'm getting 456lph.



Please can you advise optimum screen size and flow rates so i know whether I should keep pump and reduce screen size or keep screen about the same and get a new pump?

Any feedback welcome!

Thanks,

Steve.

[steve]

Ok, so where I'm getting stuck is:

Lets assume my dailing feeding is 3 cubes a day. So does this mean:
I need 36W which would be width 8cm (3") x length 30cm (12") = 36sq" or 36"?
Given a screen width of 8cm I need 480lph @ 60lph/cm, therefore my pump is more or less there?
I need 36W of light in total, so 2 x 20W is sufficient?

I would love my assumptions to be correct and I onlly need to adjust the screen size! Please can someone let me know?

Many thanks,

Steve.

[Ace25]

In inches, your screen is 11.8"x14.2".. that seems right on the edge of needing 2 CFL bulbs per side if you use 23/26w bulbs. 1 42w bulb may suffice but 2 23w would be better.

Biggest problem I see that would make your scrubber not work at its peak potential is your lighting. Your losing 50% of your light out the sides of the bulb. You either need a reflector that will wrap around the bulb (most ideal method) not just some foil behind the bulb, or buy some 23/26w CFL spotlights, or use the dome type reflectors on the curly-Q bulbs (probably the last choice out of the 3).

Are you really only feeding 3 cubes a day on a 150G tank?

You're going to want to pull as much of that algae out of the display by hand/brush, it will make the process of getting the tank back to good condition happen much faster than just waiting for a scrubber to do that much work for you.. a scrubber can eventually handle it, but it could take a year or more from that I see in the picture if you don't manually help it along by removing as much as you can by hand. Even better, I see no reason you can't remove 1 rock at a time and scrub off all the algae in a bucket of saltwater, then put back into the display and repeat. Some tanks with corals encrusting between rocks makes that option not possible, but from your pictures it seems like you could do that, at least for the majority of the rocks.

[steve]

In inches, your screen is 11.8"x14.2".. that seems right on the edge of needing 2 CFL bulbs per side if you use 23/26w bulbs. 1 42w bulb may suffice but 2 23w would be better.

Biggest problem I see that would make your scrubber not work at its peak potential is your lighting. Your losing 50% of your light out the sides of the bulb. You either need a reflector that will wrap around the bulb (most ideal method) not just some foil behind the bulb, or buy some 23/26w CFL spotlights, or use the dome type reflectors on the curly-Q bulbs (probably the last choice out of the 3).

Are you really only feeding 3 cubes a day on a 150G tank? If so, your screen to large, by probably a factor of 10. LOL

Thanks for your reply :-)

The equivalent of feeding 3 cubes a day is about right (absolute max is 4), and the fish aren't on the skinny side! So if we start with the screen size, are we defintely saying that it is way too big? What size are we saying? Would a screen width of 3" by 12" length do the job if lit on both sides? It just seems tiny?

In terms of lighting, I was struggling to find a suitable reflector here in the UK. If anyone could send me a link or even give the name of something that would do the job, that would be excellent.

I'm pretty sure the flow on the current screen is knowhere near enough...but if I could get clarification of the screen size first and work from there that would be appreciated.

Steve.

[Ace25]

ok, I was a little off with the "factor of 10" comment, but it seems with your setup going off the "feeding guidelines", a screen size of 9"x12" is plenty, or 23cm x 30.5cm, and your correct, 36w per side is the ideal # but 2x 23w would work even better.

I never really did the math with the new guidelines before now... some reason I pictured the screen size to be MUCH smaller. Reason I think that is I run a 10"x12" screen and I feed well over 10 cubes a day of food on my 75G and the screen handles it without any problems (but I use mostly 660nm LEDs). I think those "feeding guidelines" error on the side of caution by a lot (which is always good to error that direction, but it seems to really lean towards the safe side). From my testing with LEDs, I have concluded I could cut my screen size down to 6"x8" and still be able to handle 10 cubes a day when using LEDs for lighting, which if I went off the guidelines I would need a 30"x40" screen, which coincidentally seems to follow the same power savings you get with LEDs vs conventional methods (LEDs take 1/5th the power of CFL/T5HO, and it seems the screen size is also 1/5th the size, learned something new today). That is not "official", just something that my testing has proven to me and what I will be going with on my next ATS... but anyway.. you're not using LEDs so go by the first sentence to be safe.

[steve]

From the new sizing guidelines, if I'm reading correctly, 9" x 12" is too big. Shouldn't it be width 3" x 12" length lit on both sides to maximise available flow and light? I don't want to have a bigger size than necessary as this just means I need more flow and more light, right?

[DennisC]

Hi Steve.

I am using CFL's with reflectors. If you look on the bay and search Hydroponics lighting, you will find them complete with bulb holders.

Dennis

[Ace25]

From the new sizing guidelines, if I'm reading correctly, 9" x 12" is too big. Shouldn't it be width 3" x 12" length lit on both sides to maximise available flow and light? I don't want to have a bigger size than necessary as this just means I need more flow and more light, right?

ya, way to early on a Sunday morning for my brain to figure out such basic math. LOL. Now the guidelines seem much more realistic after you pointed out my error.

You are correct, 3"x12" double sided seems to be correct for 3 cubes. I was tripling both dimensions, I only needed to do one. Bigger screen horizontally would require more flow, making it 3"x12" wouldn't need as much flow as say 9"x4" since the slot/flow part is so tiny (@ 3"). You could do 4"x9" if 12" tall was a space issue on your setup.

[steve]

No worries mate :-)

I have 12" clearance in my sump from pipe to water so will go with the smaller width and save the hassle of having to buy a new pump for the extra flow I'll need. Just need to get the reflectors sorted and I'm away!

That said, I'm already seeing algae discolouration on the current scrubber and its only 24 hours old!

[SantaMonica]

I would do a 4 X 12 screen, with two (2) 33w CFL spotlights on each side (total of 4 bulbs). A 3 inch wide screen is too narrow to catch all the light.

You need very high photosynthesis power on your scrubber to overpower the algae in the display. After you have beaten the algae in the display, you can cut back on the hours of the scrubber if you want.