This is my first auto feeder in almost 4 decades of fish keeping. As with everything else I buy, I researched this purchase to death before deciding which one to get. It was harder than usual to settle on a particular one mainly because I had no prior experience what-so-ever with these. There are several to choose from and the "little details" about each are not easy to come by. In the end I bought the Eheim mainly because I found it locally at a good price and could easily return it if it didn't fit my criteria. So far I couldn't be much happier.
Overall it has the look and feel of a quality piece of equipment. It runs on two AA batteries so power failures will not affect the feeding times. A 110 volt cord with battery back-up would be better, but hey, if frogs had wings they wouldn't bump their bellies on the ground. I didn't want to spend big bucks either so I can live with it. AA batteries might be the most common ones kept in an average household too, so I probably will never have to make a special run to get them.
It came with an optional clamp to mount it on the edge of the tank, but it is equipped with four rubber feet so you can set it right on the back of the hood. It is heavy and nicely counter-balanced too, so you can feel comfortable doing it this way. It also came with a small square of Velcro to keep it from sliding or being accidentally bumped off the aquarium, but I found this feature to be rather frustrating. The Velcro is taller than the feet of the feeder and when placed according to directions, renders the feeder unstable and prone to unwanted movement. I decided to be extra careful when dabbling about the back of the aquarium hood instead of using the Velcro.
So far the flaked food I use has stayed perfectly dry and clump free. The feeder has a small fan that runs every time the drum rotates which is supposed to help with this, but I just don't see this doing much good. I think the design of the feed drum inherently does a good job of keeping out moisture and I see the fan mainly as a gimmick, but I could be wrong. What really matters is that the food stays dry, and it does. The drum holds about a one ounce can of flakes and this lasts me a long time between refills. I do have to crush the flakes a good bit because I am feeding small portions to small fish. If you have big fish you could open the adjustable dispensing hole much wider and it would probably dispense full sized flakes without fuss. If you like feeding pellets as a staple, I have no doubt these will work great.
I only wanted to feed a staple food once a day in the early morning after sunrise. I leave for work before daylight, but like to hand feed frozen treats and other things in the afternoon and evening. From what I can tell, some auto feeders require
you to feed twice a day, but the Eheim is more flexible. It lets you decide on 1, 2, 3, or 4 feedings a day at any times you wish. It also lets you decide to drop food once or twice for each feeding. If you choose two drops it rotates again a minute later. This gives slower, less aggressive fish a chance to feed after the faster ones have had their fill. This feature is a good one for my tank and I use it.
The digital read-out is easy to see and understand and gives you plenty of pertinent information. It even tells you when the batteries need to be replaced before you lose all power, and therefore your settings. Being battery powered only, I worried that I might have to reprogram it for every battery change, but this is not the case. It gives you plenty of time to do a battery change before the settings are lost. The claim for this feature is 10 seconds, but mine gives me about 20, which is plenty of time to do it without getting in a rush and making mistakes. The set-up and programming instructions are clear and easy to follow. I had mine programmed and ready to go in 5 minutes.
The Eheim is also one of the better looking feeders in my opinion. It is sleek, has a low profile, has no weird angles or sharp edges, and is rather symmetrical. There are no windows, knobs, shiny metal, or conflicting colors of any kind. It doesn't grab your eye and scream, "HARDWARE!", like some others I've seen. I set mine on the back of the hood behind the light and you can barely tell it is there. I do consider this aquarium to be a "show tank", so I appreciated the unobtrusive looks.
Several reviewers complained about the battery door not staying shut, but this hasn't been a problem for me. However, I can see where you would need to be cautious and handle it carefully so as not to break a plastic tab that would cause this. A few also complained about the battery contacts corroding prematurely. This, (along with the fact that the fan that blows air over the food sucks through the battery door), is probably why the instructions are very specific to keep this part of the unit away from openings in the tank to prevent moisture from entering. I did exactly that and do not anticipate any corrosion problems.
The only serious complaint with my new Eheim feeder is the humongous hole you need to cut in the hood to get the food to land in the water. The feeder intermittently drops food through almost 180 degrees of it's rotation, making for a very large food "footprint". I overcame this by fabricating an elaborate, V-shaped "catch basin" from Plexiglas to funnel things into a 1/2 inch square hole, but believe me, not everyone would be capable of this or willing to invest the time and effort. It took a very determined me about 8 hours to source the materials, design, test, and build one that looks professional and works every time. (I should patent the thing!) Most will just have to live with about a 4 inch security breach in their tank hoods and refrain from keeping escape artist critters like eels, frogs, and probably even certain jumping fish. This was not an option I was willing to accept. I do believe however that the rotating drum - which is the reason for needing such a large hole - is still the best all-around design for keeping food dry and fresh, operation simple and dependable, and costs low. As a matter of fact, I didn't see another feeder at any price that I thought would drop the food through a smaller hole - at least not one I personally would have considered. I would gladly pay 3 times what the Eheim cost me to get a feeder only as good if it would also drop food through a dime-sized hole, but I don't think one like this currently exists.
Anyone who is going to purchase an automatic feeder should consider the Eheim 3581. Over-all it is a fine piece of equipment that works as advertised, maybe even better. It is so versatile that a lazy aquarist could get by without ever hand feeding his fish, though I would never recommend it.
If anyone has first hand experience with other makes or models I would love to hear about them too, especially if it will drop food with pin-point accuracy.