2 Frozen cubes, or
20 Pinches of flake, or
20 Square inches (125 square cm) of nori, or
5.6 grams of pellets
The number of gallons or liters of water in your tank or sump does not matter. If you feed more than the above amounts you can get multiple HOG2 units; multiple units are preferred over one larger unit because you can clean one unit per week, and because you'll always have one unit filtering while the other one starts growing again after a cleaning. Multiple units are also good for backup. The magnets attach the outside cover to the inside cover through the aquarium wall, and can be used on glass or acrylic 1/4 inch (6 mm) to 5/8 inch (16 mm). Not more. If your aquarium wall is 3/4" (18mm) it might work but you won't know until you try; it would be better to put the HOG2 in your sump instead; it will work the same.
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Compared to the HOG1.3
which look the same in size, the HOG2 is meant for situations which have some nutrient or algae problems but the rocks in the display are not covered in thick green hair algae. The large inside space of the HOG2 growth compartment allows for lots of build up of algae, and the 4 LED light grows green algae in situations where the lower power of the HOG1.3 would only grow brown algae. So this HOG2 model is great for aquariums that have been running for a year or more and the display rocks have already filled with phosphate, and are thus starting to show algae on them. However if the display is full of green hair algae and thus the nutrients measure zero in the water (because the algae on the rocks is absorbing them), then the stronger photosynthesis of the HOG3 would be better than this HOG2, so as to be able to out-compete with the photosynthesis on the rocks.
The Green-Grabber (tm) algal growth surface is so rough and prickly that it might be the roughest thing you've ever felt. A cactus might be sharper, but that's about it. Rough surfaces are critical for allowing algae to attach and grow and thus provide strong absorption of nutrients. The rock-hard protrusions stick straight out 1 to 3 mm. Old style algae scrubber screens are made from "slippery" plastic canvas that is used for sewing and knitting; algae takes a long time to attach to it. Green-Grabber (tm) growth surfaces are not plastic at all; instead they are rock hard and have jagged rough edges and points (don't let children play with them). Green-Grabber surfaces are so good at grabbing algae and letting it grow that if you have high nutrients you may starting seeing tiny growth spots within hours instead of days. And the white color of the Green-Grabber surface reflects as much light as possible, getting almost the effectiveness of a 2-sided growth surface even though it really only has a light on one side of the surface.
This is a hand-built Hang-On-Glass® (HOG) Upflow Algae Scrubber® (UAS) with a Green-Grabber
growth surface, for glass or acrylic 1/4 inch (6 mm) to 5/8 inch (16 mm)
thick. This is the typical thickness range for most aquariums, and larger sumps, however you should measure yours to be sure. If your tank uses thin 1/8" (3mm) glass such as many low-cost 10 gallon aquariums do, this filter is not recommended because the magnets are strong enough that they might crack the glass. You would be better off getting a lower cost HOG.5 filter HERE
No electrical parts go inside the aquarium; only air. And the air bubbler is already supplied (it's sealed behind the growth surface), so you don't have to get an airstone. The bubbler is simply vinyl air hose that has been cut lengthwise, and with cross-cuts, to form little flexible segments that are both adjustable and open-able to allow for easy cleaning. This HOG2 will run on both 120V and 240V, and comes with a 10 ft (300 cm) power cord with a U.S. plug. If you require a different plug you can get an adapter at any local hardware or travel store, or online, or you can cut off the U.S. plug and install your own plug from a hardware store.
Comes with 3 ft (90 cm) of vinyl airline, but requires an air pump that can pump at least 2.0 liters per minute (.07 cfm), preferably more. A pump that says it can handle 2 or more airstones/outlets, or a pump with 2 tubing attachments instead of one, will be needed. You can have as much air as you like, however; 10 lpm pumps are no problem (although it will be louder). One powerful pump which works exceptionally well is the Whisper AP 300 from Tetra. You will need to combine the two outputs into one to feed the scrubber, using something such as the "Tee" air line tubing fitting from Tom Aquatics. Make sure to put the air pump above the aquarium so that it will not drain any water if it shuts off, or use a one-way valve on the airline if the pump is lower.
Comes with 4 red (660 nm) 3-watt LEDs, which are attached to a heat sink inside the cover. The LEDs will give the aquarium or sump a slight red color at night when the aquarium lights are off. You will need to get a timer so you can run the LEDs for up to 22 hours per day (not 24). The LEDs never needs replacing.
The HOG2 growth surface will need to be cleaned every 7 to 21 days, by removing the inside cover, disconnecting the airline, and taking the inside cover to the sink so you can brush the algae off of the growth surface and the bubbler with a toothbrush. No hard scraping is needed; just brush it with a toothbrush. The Green-Grabber growth surface is permanently glued to the inside cover using epoxy, however a few of the Green-Grabber particles may dislodge during the first few cleanings, which is normal. Cleaning the growth surface, bubbler, and the inside cover takes about a minute with a toothbrush.
This HOG2 comes with a 1 year warranty: Warranty is for replacement or repair only; not a refund. Costs for shipping back to us are not covered; you will need to ship the entire unit back to us before we can ship a replacement. Warranty is limited to repair or replacement, and does not cover fish loss, personal injury, property loss, or direct, incidental or consequential damage arising from the use of it. The warranty and remedies set forth above are exclusive and in lieu of all others, whether oral or written, express or implied. We specifically disclaim any and all implied warranties, including but not limited to lost profits, downtime, goodwill, damage to or replacement of other equipment and property, and any costs of recovering animals, plants, tanks or other aquarium related items and/or equipment. We are not responsible for special, incidental, or consequential damages resulting from any breach of warranty, or replacement of equipment or property, or any costs of recovering or reproducing any equipment, animals or plants used or grown with this product.
Can be shipped to any country; you can find shipping costs by using the shopping cart; be sure to click "display rates". If you don't have a zip code, enter "zip code" instead. Note that shipping outside of the USA will probably require you to also pay an import charge when it arrives. We cannot mark it as "gift". The lowest cost (but slowest) foreign shipping is generally USPS First Class Package International, but USPS Priority Mail International is better because it is faster and has insurance. The size of the shipping box is 10 x 7 x 5 inches (25 x 17.5 x 10 cm).
HOG2 size: Each cover is 6 5/8" wide x 8 3/4" high x 1 1/2" thick (16.6cm wide x 21.9cm high x 3.75cm thick). It requires at least 7" (17.5cm) of water to operate in.