Submerged, rotating cylinder algae scrubber (with video)

It's taken a while to get here, but the scrubber is finally operational
Have switched out the Eheim 600 pump I had for the Eheim 1000, as the tubing matched the hose barb better, upside is that it spins a bit faster too, downside is that it's a bit noisier. I also got some smaller brackets laser cut, which fit this tank much better.
Note that the tank that this scrubber is on has only been up for a day, so it probably has not even started cycling. I added some food last night to kick it off.

Each Monday I'll be posting updates regarding growth (if any), and the ammonia/nitrite/nitrate/phosphate levels of the tank. I'll add pics/vids as well if there is visible growth.

Obligatory pic and video

 

First test was today, didn't bother checking nitrite/nitrate because I'm only at the start of the cycle.
Ammonia: 0.25ppm, Phosphate: 0.4ppm

 

Finished first week of cycling:
Ammonia: 2ppm
Nitrite: 5ppm
Nitrate: 40ppm
Phosphate: 0.47ppm
No growth on scrubber.

Surprised that I've already got relatively strong nitrite and nitrate readings. All the rock in this tank is dead/dry rock.

 

I'm not sure, it's spinning quite fast, but not crazy fast. I've got the lights at 40% intensity.
I have no idea on how long an algae scrubber takes to grow algae when you're cycling, in my experience green algae isn't seen for a while after setting up a new tank, so not really expecting much. I think I'll leave it for at least a couple of months, then if I still have no growth, I'll start adjusting the flow and lighting.

 

Added some live rock today, had a thin covering of hair algae in some areas, so at least I know now that it's definitely in the tank.

 

Finished second week of cycling:
Ammonia: 0ppm
Nitrite: > 5ppm
Nitrate: 160ppm
Phosphate: 0.48ppm

Looking a bit ugly at the moment. Diatom algae has taken off in the scrubber, both on the some of the acrylic and also the screen.
I looked at the screen less than 24 hours ago out of curiosity, and the diatom algae was about 1/3 of what it is now. The algae is contained to the scrubber itself, there's none in the sump or the display tank, so I'm pleased about that. Hopefully if GHA starts to grow it's contained to the screen, unlike the diatoms.

 

Small update, going to give it a clean today as it's covered pretty well in diatoms.

 

Finished third week of cycling:
Ammonia: 0ppm
Nitrite: 0ppm
Nitrate: 5ppm
Phosphate: 0.58ppm

Looks like I'm close to the end of the cycle. Cleaned the screen of diatoms again yesterday. The diatom outbreak has been contained to the scrubber so far, not a trace anywhere else in the tank or sump. No GHA growth yet.

 

Finished fourth week of cycling:
Ammonia: 0ppm
Nitrite: 0ppm
Nitrate: 0ppm
Phosphate: 0.59ppm

Still growing brown algae / diatoms on the screen at the moment, getting cleaned a couple of times per week. No GHA growth yet.

 

Fifth week update:
Nitrate: 5ppm
Phosphate: 0.68ppm

Diatom algae still growing on the scrubber. There was also some green hair algae growing in a few spots, but the diatoms were covering everything else. I cleaned the screen again, hopefully when the silicate has been depleted the GHA will have a good chance to take over the screen. Lights are at 80%. Funnily enough, even though the scrubber spins at between 150 - 180 RPM, amphipods have no problem holding on to the screen. I often see them cruising around on it if I disconnect the water pump and look at the screen.

Am working on revision four, changes will include:
Scrubber being orientated vertically.
The rod will be made from acrylic (currently nylon), and it won't have to be removed to remove and clean the screen.
Less (hopefully very little) light escaping the edges of the scrubber through the glass.
Cleaner looking back on the LED side (white nylon screws not visible).
PCB size reduction, also now housed inside the LED housing.
More deep red LEDs (six), not sure if I'll keep both the blue and the violet. Possibly just the violet.
Remote control attached to LED housing.

 

I did actually plan on making the fins curved which will give it more torque, but to be honest, there's a tonne of torque on this thing already. I really can't see even thick algae growth slowing it down much, but time will tell. I'll have to make some changes if it does
Also in revision four, very little light will enter the wheel chamber. That U shape I have currently (to remove the scrubber and wheel) won't exist.

 

Had a look at the scrubber today. More diatoms growing on the screen, but also quite a bit of white stringy algae, a few mm long.
Pretty odd, I've never seen it before. I think it's probably come from me having the LEDs on for too long (18 hours), so I've dropped the duration back to 12 hours and reduced the intensity of the LEDs from 80% to 60%. I might drop the duration back further, but will see how I go with it like this first.

 

Sixth week update:
Nitrate: 0ppm
Phosphate: 1.13ppm
Still plenty of diatoms growing on screen, but it feels like that is starting to wind down now, hopefully anyway. Cleaning the screen of diatoms also gets rid of any small patches of GHA, so not much to report on that front yet. Still seeing plenty of small white strands of (dead?) algae.

 

That makes sense. I initially had the LEDs on for 12 hrs/day, then over enthusiastically raised them to 18hrs/day, which I've since knocked back and have noticed the GHA begin to return. I'm going to update the controller today so that the hours per day can be adjusted from 6hrs to 21hrs/day in 3 hour increments. I'll probably add a few more options for the intensity as well.

 

Seventh Week Update:
Nitrate: 10ppm
Phosphate: 0.91ppm
Still getting diatoms all over the screen. It's getting pretty annoying now. I purposely didn't clean a ~2cm strip on the side of the scrubber for a couple of weeks. Green hair algae is definitely growing through it, but there's a thick coat of diatoms as well.

I have some PhosGuard lying around. It claims to remove silicates as well, maybe I should use some.

-Update 21/04. Added 125ml of PhosGuard near the return pump.
-Update 23/04. Removed the Phosguard. Phosphates have dropped to 0.56ppm, so hoping that the silicates have been removed.

 

Eighth week update:
Nitrate: 5ppm
Phosphate: 0.04ppm

Was still getting diatoms growing on the screen with the phosphates at 0.56ppm, so I re-added the Phosguard to the tank a few days ago. The phosphate has dropped considerably since then. Diatom growth has slowed down, I wiped a small amount off the screen today and will leave the Phosguard in there for another day then remove it. The screen appears to be greening up now.
I think a lot of the problems with the diatoms in this tank is because I don't have any lights over it, which likely would have expended the silicates much faster.
Also, made a bunch of changes to the controller, intensity now goes from 50-100% in 10% increments, and the duration goes from 6 to 21hrs in 3hr increments.

 

Ninth week update:
Nitrate: 20ppm
Phosphate: 0.60ppm

GHA growth now appearing on the scrubber, with more green growth each day. I think all the white behind it is dead diatoms. Had to clean the inside of the scrubber, the acrylic, as there was brown algae on that.