New Santa Monica RAIN2 Algae Scrubber

The screen will take time to fill in so that the scrubber can start out-competing the GHA in the tank.

The bare spot is likely right in front of the LED strip. You are getting growth around the edges of the screen, which means the tank/water conditions in general are good for growing algae, but the intensity of the light is too high right in front of the light strip. Here, you are seeing photosaturation, at least on the surface. With the 3D printed screen (which I believe has 2 layers and a bit of a void space in the middle) there will be some growth there, but it will take a while to fill in on the surface.

Since you can't dim the lights, I would try breaking up the photoperiod a bit. Instead of 18 on (all in one continuous photoperiod), make that 3 on 1 off, repeat.

 

Off time does not matter much for algae IMO. At first, it's only because the incoming light can't be adsorbed by enough algae, because there is not enough algae there. Once you get growth kicking in, many times you can increase the photoperiod as much as you want but I would ramp up to that over time.

That works to an extent, but you're also going to eliminate the bacteria and essentially start over. With reef tanks, there is a longer cycle of maturation so often techniques like this just push off the maturity of the tank.

Depending on how old the tank is, this might just be a phase that will pass with time (and the scrubber will help). To start off, you will want to pull the algae off the rocks. You can do this in the tank using a soft toothbrush, but take it one step at a time. Use fingers if you can, then a toothbrush but you're not wanting to scrub - it's just that a toothbrush can snag algae and hang on to it better, so you're really just dragging it over the algae to pull it off without disturbing the surface of the rock where the bacteria is colonized (referred to as the periphyton)

If you scrub, you remove the periphyton and this delays your tank maturation as this has to rebuild. Many times the bacteria that are colonizing are also liberating the bound phosphates and then the algae grows from that (that's a simplified explanation but essentially that's the mechanism, at least in theory)

So in essence, you actually want the algae to grow in the tank somewhat. Sounds a bit backwards, but in the long term, you'll get a mature and stable tank faster if you manage it rather than putting a flamethrower on it.

Also, see #15 here: Mything the Point, Part Three: Conclusion - Reefkeeping.com

 

Absolutely. Some take a few weeks, some take 6 months or more. It is very much dependent on the individual system

No, it will probably help the scrubber grow, but I honestly think that is a last resort. Keep the tank algae at bay for a while first, let the scrubber become dominant. Do water changes if necessary to lower nutrients.

I think many people want the scrubber to lower the nutrients in a system where they are already elevated. Sometimes this works. But, it's better to consider the scrubber a long-term solution, that being keeping the nutrients low. So as the scrubber ramps up growth, maintain a standard husbandry regimen. Once the scrubber kicks in strong, then you can rely on it. You can't rely on a scrubber from day one (at least not in a majority of cases).

Scrubbers are a workhorse once they're "broken in" per se.

 

Plus keep on top of the tank algae. Gentle toothbrushing to gather up the algae

 

I wouldn’t yet. Just rub & rinse. One of the main mistakes is harvesting too often or too vigorously.

Rub & rinse will dislodge a bit of growth - the poorly attached algae. That’s good enough.

 

Not in my opinion. It won’t stay in place and would just get photosaturated.

 

I wouldn't scrape until you have growth covering the entire screen. You're still in the rub/rinse stage IMO. You might scrape off about 25% and just around the edges, but that's about it.

As always though, scrub the slot and the top edge of the screen for sure.

 

run under room temp tap water and gently rub with your fingertips