From the inventor of the original waterfall algae scrubber in the year 2008 finally comes the first new version: the patent pending RAIN2. The underwater submersible GEM5 lights (also patent pending) allow the RAIN2 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 mounting option (recommended but not included) means you don`t even need a shelf or a bracket to place the RAIN2; just use your pole mount to set it on the bottom of your sump. You can fit two RAIN2 units into the same space that other waterfall algae scrubbers take for just one of their units. (Note: 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.)
The RAIN2 will do most of the filtering needed for your fresh or 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.
The RAIN2 with 4 GEM5 lights has the same growth surface area and feeding as with 2 GEM5 lights, but the high level of light of 4 GEM5 lights works well when nutrients in saltwater are high, and when nutrients are very high in freshwater such as a highly fed community tank.
Drain Pipe: Although a drain pipe is not needed, you can add one by using a standard 1" ID drain bulkhead which fits standard 1" (25mm) schedule 40 pvc pipe. The drain hole in the tray is 1 3/4" (44.5mm) diameter.
Head Room: If you are installing the RAIN2 in a sump or cabinet area with limited space, the RAIN2 will need 4" (10cm) above the top of the light-cover dome lid in order to remove the lid. However you can lift the whole tray unit up off of a pole mount, with as little as 2" (5cm) head room, and then remove the light-cover dome lid in your sink.
If you commonly have power outages, traditional waterfall scrubbers will dry out after a few hours, but you can prepare for and prevent this with your RAIN scrubber by placing it low enough in your sump (even slightly underwater if needed) so that when the power goes out the water level in the sump will rise up high enough to keep the screen under water. The GEM5 lights will not be harmed at all because they are designed for underwater use. With the screen submerged like this, it can last for several days with no flow or light.
The GEM5 lights can be put on a timer so that they stay on for part of the day, and off for the rest of the day, to possibly improve growth and filtering. However you can try 24 hours of light (no timer) if you like because sometimes it does work well in freshwater, or in saltwater with high measured nutrients such as more than 1.0 ppm phosphate.
The RAIN2 requires a water pump that can pump at least 200 gph (760 lph) water flow 24 hours a day. 300 gph (1135 lph) might be better to fill up all areas of the screen. The height ("head") of the filter above the sump water level will require that the pump be able to pump up to that level and still be able to supply enough water. Generally, a 400 gph (1500 lph) pump with an adjustable output works in most cases. The water can also be fed from your display overflow; any type of overflow system (Herbie, siphon, etc) will work.
* Water Changes: If you have been doing water changes to reduce nitrate, phosphate, or nuisance algae, then an algae scrubber filter will greatly reduce the need for them and may possibly eliminate them. When algae grow in the filter, they consume nitrate, nitrite, phosphate, ammonia/ammonium, metals, CO2, and some toxins; so it’s just a matter of growing enough algae inside the filter to do the filtering you need, compared to how many nutrients you are putting into the tank with the food you feed (that is why the RAIN filter is sized for a certain amount of feeding per day). However, this filter (and algae in general) do not supply calcium, alkalinity, magnesium or strontium. So if you wish to reduce or eliminate water changes, you will need to supplement any calcium, alkalinity, magnesium or strontium that you were depending on water changes for. Freshwater aquariums, which may only need alkalinity (hardness) to be maintained, may get enough alkalinity from just doing evaporation top-offs with tap water from your sink.
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