Santa Monica Filtration

Santa Monica Filtration RAIN4 Algae Scrubber


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Santa Monica Filtration RAIN4 Algae Scrubber


  • Pole mounted waterfall algae scrubber ATS for saltwater sumps
  • Waterproof submersible GEM5(TM) lights, Green Grabber® screen, and pole mount
  • Eliminate waterchanges, remove nuisance algae, nitrate and phosphate
  • Cultivate algae for feeding.


  • Dimensions **without** pole mount: 10"L x 5"W x 13"H (25cm x 12.5cm x 32cm)
  • Dimensions with pole mount will depend on your choice of pole mount segments
  • Operates on both 120 and 240V

Welcome to algae scrubbers. We are the only source for patent pending waterfall scrubbers that use our new dome/tray combination. All the oceans, reefs, lakes and rivers are naturally filtered only by algae, and all organic particles remain in these waters to feed the animals. Reduce your glass cleaning and water changes, and create an environment for living micro-animals to grow inside the scrubber. No more dosing or possible overdosing of chemicals. No more refilling media. No more pale corals from low nutrients, and no more sick animals from high nutrients. Far more powerful than chaeto or refugiums, and does not remove any food particles. And you can use the algae as food!
The RAIN4 will do most of the filtering needed for your saltwater aquarium, and in most cases it will do all the filtering if it is the proper size for your amount of feeding that you do and the amount of rock that you have. Part of this filtering includes helping eliminate two very important things that drive most aquarium owners crazy: Algae and waterchanges. The filter works by growing algae on the screen, and these algae consume all the "bad" things out of the water*. This is how all the oceans, and all the lakes, are naturally filtered.
Because of the high filtering photosynthesis of our scrubbers, it`s not recommended to run them with macro refugiums or chaeto reactors, because the macro or chaeto will die and the nutrients will be absorbed by our scrubbers. 
From the inventor of the original waterfall algae scrubber in the year 2008 finally comes a larger version of the popular ATS waterfall RAIN2: the patent pending RAIN4. The underwater submersible and electrically safe GEM5 lights (also patent pending) allow the RAIN4 to be placed in your sump anywhere you like, as low to the water as you like, which saves a lot of space. And the pole mount (included with the RAIN4) means you don`t even need a shelf or a bracket to place the RAIN4; just use the pole mount to set on the bottom of your sump. You can fit two RAIN4 units into the same space that other waterfall algae scrubbers take for just one of their units.  
The pole mount that is included with the RAIN4 is recommended for the easiest and most sturdy operation, and it has multiple height adjustments. However the pole mount is not mandatory; you can use a shelf or other technique to mount the RAIN4 similar to the smaller RAIN2 if you wish.  
Safety is a prime concern, and our GEM5 lights keep the 240 or 120 volts far away (2 meters way), with only a safe low voltage going into your sump area. The system is so safe that you could cut the GEM5 lights in half and put them in saltwater and nothing would happen. Other waterfall scrubbers, however, use so-called "waterproof" Chinese lights that are bolted onto the outside of the scrubber box, and the 240 or 120 line voltage comes right into the sump area. Not only are these lights not waterproof (don`t ever put them in water), they are not even water resistant, and salt creep will eventually get inside them, causing an electrical hazard. Our power supplies are UL and Canadian UL certified. The Chinese lights that others use, are not. 
Also included with the RAIN4 is a 2 mm thick, 2 sided, patent pending Green Grabber® algae attachment screen. The screen is also sold separately HERE for DIY, and it is the modern replacement for the old hand-scrapped plastic screens. It is 3D printed in Rough 3D (TM) and has far more algal-attachment surface area than hand-scraped screens. Also, similar to our air bubbling upflow UAS scrubbers, the screen of the RAIN4 is surrounded by air so that when algae growth is strong on the screen, the algae can get the carbon it needs from the CO2 in the air (instead of from the alkalinity in your water) after the CO2 in your water is used up. Thus the scrubber growth (filtering) is not limited by your alkalinity and CO2 in your water, and your alkalinity will stay at higher levels. This is compared to sealed chaeto reactors which don`t contact air and thus must get all the carbon it needs from your alkalinity, which causes the alkalinity to drop faster, and the growth to slow down. 
The RAIN4 comes with 6 of our GEM5 lights, which will be already mounted to the inside of the dome lid cover. The GEM5 lights are also sold separately HERE and you can add more of them to the dome lid by using silicone glue if you wish. The RAIN4 also includes 2 power supplies (the RAIN2 only has one) so that you can start off with fewer lights when needed, and can control them easier with a controller if you have one. Two power supplies is also great for backup, in order to always have some of the lights operating (photosynthesis water filtering only works when illuminated). 
Aquarium size: The RAIN4 has 48 square inches of 2-sided growth surface and is designed to be the only filter on an aquarium that is fed up to:
  • 4 frozen cube per day, or
  • 40 pinches of flake food per day, or
  • 40 square inches (240 sq cm) of nori seaweed per day, or
  • 0.4 dry ounce (11.2 grams) of pellet food per day.
The amount of water in the aquarium, or the dimensions of the aquarium, are not important. If you feed more than the above amounts, you can use additional RAIN4 filters (or use our SURF, HOG or DROP filters) to add up to the amount that you are feeding, and then clean one of them at a time on a rotating schedule (one per week, etc). If you feed much less than these amounts, and the aquarium is very small, then it will still work but you just need to find a place where the filter will fit. It’s not possible to over-scrub.

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