Scrubber + Skimmer in a FOWLR?

[JulioC]

I currently have an 85 gal tank (45 gal main display and 40 gal sump with caulerpa). I have a Deltec APF-600 skimmer.

I´m lazy cleaning the glass so I have alga in my tank and sump. I think that an ATS will be more efficient than caulerpa removing nitrates and phosphates. I´m planning to replace caulerpa with a ATS but maintaining the skimmer since I only have fish and the skimmer only consumes 10W and removes a lot of junk.

Bioload is: 2 large Ocellaris and 20 small ocellaris in the sump (less than 1 inch) and more comming :D :D.


My question is: Should I start my ATS with 85 watts of light or since I have an skimmer I can start with half?

[Floyd R Turbo]

Normally you would just size it for the sump, but with that many fish and an inhabited sump, I would opt for total volume, and size the screen and lights for the full 85 gallons. Better yet, round it up to a 100g system. 4x24W T5HO is perfect for that size, if the fish are sensitive to the water quality, oversize the scrubber and design for a 100 gallon system. Better to have too much than not enough IMO

[JulioC]

Normally you would just size it for the sump, but with that many fish and an inhabited sump, I would opt for total volume, and size the screen and lights for the full 85 gallons. Better yet, round it up to a 100g system. 4x24W T5HO is perfect for that size, if the fish are sensitive to the water quality, oversize the scrubber and design for a 100 gallon system. Better to have too much than not enough IMO

Yes, I was thinking in 85 W setup counting the full 85 Gallons. I´m curious if I can reduce the Watts and square inch since I also have a good skimmer that should "procesate" excess food.

[Floyd R Turbo]

Since you have no corals, you don't care about starving them or not. So running a skimmer wouldn't harm anything. As far as undersizing a scrubber for a multiple filter system, sounds reasonable. They're both supplemental filtration so you would need both. You could always do a 100 scrubber and run the lights a few hours less per day, and you would have extra capacity in case of a need, like a huge batch of fry, or desiring to feed a ton more to increase growth rates without spiking ammonia. Remember that skimmers do not remove ammonia, while it is the favorite 'food' for a scrubber.

[JulioC]

You could always do a 100 scrubber and run the lights a few hours less per day, and you would have extra capacity in case of a need, like a huge batch of fry, or desiring to feed a ton more to increase growth rates without spiking ammonia.

Yes, it is a good idea to prepare it for 100 gal to be prepared.

Would you use lights less hours a day or would you use lights just in one side? (the other side in case it is needed)

[SantaMonica]

Less hours of strong 2-sided light is always better than weak or 1-sided light.

[JulioC]

Thanks, I´ll reduce hours but with the full setup.

I thought I read that less hours implies growth of brown algae instead of green in the ATS.

[SantaMonica]

I thought you wanted less power.

Just run it 18 hours.