View into the sump showing one of the pumps (bottom, left-hand side), and a colander with crushed coral that has a titanium heater lying on top. There is quite a bit of debris in the sump, but the water is crystal clear. The bright blotches are duck weed that is floating on top of the sump. It dies off in the darkness of the cabinet.

My pumps are two magnetic drive pumps manufactured by Danner. There is a range of models available with different flow rates. I am currently running two Mag Drive 18 with a maximum flow rate of 1800 gph at 0' pump head. I have a pump head of about 5' over the back of the tank, leading to a maximum flow rate of about 1200 gph per pump, or 2400 gph combined. The data sheet for this pump in PDF format can be found here.

Danner MagDrive pumps are sold under both, the Supreme brand name (marketed for aquariums) and the Pondmaster brand name (marketed for ponds). Supreme and Pondmaster pumps are identical except for the power cord, which is longer for the Pondmaster pumps (something like 10" versus 18", but don't hold me responsible for the exact length). I have one of each, because I bought them refurbished from a guy via eBay, and I cared more about the price than the name on box. If you have an opportunity to get these pumps used or refurbished, I would wholeheartedly recommend it, because they are virtually indestructible. Unless the previous owner has run a train over them or blown sand into the intake, they should be good to go no matter how old they are. Sand in the intake is obviously are more likely scenario than the train, so that's something to look out for with these pumps - as with any pump. Even if this has happened though, a new impeller assembly, which is readily available as spare part, will make the pump as good as new. A good place to buy Danner Mag Drive Pumps new is Petsolutions. They run specials on these pumps quite frequently, and the price you get then is usually the cheapest you can find them for anywhere else.

I am extremely happy with these pumps. They are built like tanks and virtually maintenance free. I am also a huge fan of Eheim classic series canister filters, and these pumps use the same magnetic drive technology as the pumps Eheim employs in those filters. The only removable part is the impeller, and that is easy to clean and easily replaced, if that should ever become necessary. The pumps are also very reliable, and start up invariably without a hitch (which can't be said about all of their competitors - Rio pumps have a notorious reputation in this regard, although I have never used one of these myself). Last but not least, the Danner MagDrive pumps are super quiet - at least in the way I have them installed. The pumps can be used submerged or in-line. Obviously they will be more quiet when used submerged, because the surrounding water will dampen the noise, and that's how I am using them. In addition, my sumps are enclosed in the cabinet of my stand, and when sitting in front of the tank the pump noise is barely perceptible. When sitting in the living room at night when everything is quiet in the house, my brand new, very quiet fridge in the kitchen, when cooling, will simply drone out all noises from the tank, including the small part of the noise created by the pumps.

When writing this, I checked the reviews of these pumps on Cichlid-forum, expecting them to have the maximum user rating of 10 or at least very close to that. To my surprise, the only get a miserly 8.8. Things people complain about are that you have to do your own plumbing - give me a break, this is just a pump, not a whole filtration system. Also, that you have to monitor the water level in your sump - no pump will help you if you let your sump run dry (but an automatic water change system might be able to prevent this from happening!) The most important complaint is about excessive noise that these pumps create. I have not the foggiest idea what these people have been smoking, but it must have been good, because they sure are hearing voices!

Kidding aside, one possible explanation could be that these people use the pumps in-line in a setup consisting all of sturdy pipe without any flexible hose. In such a setup pump vibrations will propagate throughout the whole plumbing, and not only cause excessive noise, but create stress on the pipes, which over time can lead to leaks and breakage. I learned this when setting up a high vacuum system in a chemistry lab while doing my PhD. The only time I had noise problems with magnetic drive pumps was when the impeller shaft was broken. This happened with Eheim pumps though that had a ceramic impeller shaft. I have not had any trouble with the Danner pumps. One thing you could do if you want to take extra good care of the pumps, and your mechanical filtration is a bit lacking, is to use a sponge pre-filter available for these pumps instead of the regular pre-filter. The regular pre-filter would only serve to prevent a fish from swimming into the pump, or you sticking your finger in there. The sponge pre-filter will be a lot more useful in that it takes care of smaller particles and provides some bio-filtration. I've recently upgraded to the sponge pre-filters, which are well under $10, and more than worth the money.

One more word about using these pumps submerged. Obviously they will create some heat which they will pass on to the water. For me living in Ohio where I have to heat the house for most of the year and the tank for even longer, this is actually a benefit. For the few days in summer where this might be a problem, I have the air-conditioning on in the house anyway. However, if you live somewhere where you are just tossing up whether or not you need to buy a chiller for your tank, installing the pump inline and thus preventing it from passing the heat on to the tank water, could help you avoid having to make this investment.