I have to say , whatever you choose, be very careful to follow the instructions that come with the filter "exactly" or even to the "conservative" side. I used a powerfilter years back, that relied on diatomaceous earth , and sometmes activated charcoal, to quickly clarify aquarium water , though it was meant to be only an occasional use and not a 24 hour a day application for the filter. At any rate it would remove the smallest possible particles suspended in the water, and the carbon various chemicals as well that discolored the water. It recommended only putting 1/4 the usual amount of carbon for the first use in the aquarium , as sometimes overly fast changes in chemestry etc. in the tank can harm the fish. Wanting a quick result I put the whole amount of carbon in at one application and left the house with the filter running to go to work. Living next door at the time to where I worked I had an uneasy feeling midway through work and managed to duck out for a while to check my aquarium , only to find many of my large prized angel fish swimming upside down and in circles and gasping for air. I ran them over to another tank , turned off the new filer , and then had to go back to work. Unfortunately more than half the affected fish were dead, when I returned home later that night. Perhaps this is an "obvious post" to many aquarium lovers and those with lots of experience, but even I with a science backgroud, got a little too eager and impatient for the health of my fish. I found the design of my diatom filter most odd and incovenient as well, and most likely newer designs are easier to use, but mine consisted of a glass jar with a bag attached inside the jar to a top pump with the inflo into the jar , which contained the diatom earth and then through a bag to the outflow back to the aquarium. The loose diatom earth, would be sucked at starting the pump so that it coated the outside of the bags where the water passed through to the inside and the outflow, but sometimes the bag would not coat properly and instead would force the diatom earth right through the bag and right into the aquarium, and that would allow the fish to get the stuff right into their gills, though I always watched at that first step of "coating the bag" to make sure they weren't exposed to large amounts of the earth;otherwise the fish might have been killed by the diatom earth or at least injured with much exposure , I'd think? Oh well this has been a lengthy post and I'm not familiar with all the newer designs for various filters etc. and most likely they're better designed nowdays and safer and easier to use, but if you've had another type of filter on your aquarium for any length of time, I'd consider keeping a close eye on your fish while trying new filers etc. so any quick changes in water quality and chemistry could be detected with any changes in the fishes behavior , so you could turn off the new filers, before disaster strikes. Most likely it won't!!

holy cow! thanks for the warning. i read an availble d.filter instructions for use that said if not done so properly de would get into the water, but would be sucked back up and not create a problem. hmmmmm.

on that note, i am sure it could cause gill injury if in excessive amounts. after all, it kills flea larvae and other soft bodies insects through dessication. supposedly, it is "jagged" and causes little cuts and abrasions.

certainly something to think about.

It seems with some fish , especially those, that may encounter some muddy water from time to time with all kinds of very small paricles in itm that most do have efficent means of ridding their gills of any particles that might stick to their gills via various secretions etc. that tend to clean their gills naturally , but as mentioned those diatom shells are sort of a different "animal" and being sharp to the extreme, they might just make their way into the gill tissues, and that couldn't be good. I was very lucky on those occasions when , the earth made it back to the aquarium , there never seemed to be any damage to the fish, even with very small amounts making their way into the tanks. I must start visiting more aquarium shops again, so I can get a better idea how modern filters are constructed, but reading one site , I'd say, that even with the most sophisticated filters avaiable nowdays, it's still recommended to ecchange up to thrity percent of the water with fresh water on a fairly freqent basis for fresh water tropical aquariums, and that was suggested even almost thirty years ago, so there are still limits, as to what any type of filer can do. I guess however , with the extreme sensitivity of marine fish, those aquariums most likely need few water changes, as that could make for some very uneven water quality, and the big Public Aquariums with huge marine tanks may have methods that require almost no replacement of water?? Any of you marine enthusiasts know the answer to that one??

I don't see how the diatom powder could be forced through the filter bag. The diatom filters are pretty much the same today but uses a plastic jar. I've been useing a DE filter for over 30 years without a problem.

Perhaps the DE used in Bird's filter was not aquarium grade? I have gotten the DE powder in the water before with no ill effects. It was a concern of mine before using it about some of the powder getting in and causing damage. After a few aquarists told me that it would not be a problem, I tried it. Mine is a DIY jobby. It is only used for water polishing. Sometimes in my I get alot of "particles" floating after a PWC. The aquarium water is usually crystal, but after an hour or 2 of the DE it is deffinately clearer.I have never had a problem with any nutrients being removed. I dont think that can be possibly done with a DE unless it heas a high pressure pump and is tightly packed with powder, even then it is questionable as to what nutrients have been removed if any. I tested the water parameters afterward, was concerned of that, nothing removed except a little algae and very small particles. I think the only way to remove metals and nutrients is with RO/DI. Most DE filters have a micron filter that holds the DE back from entering the water. You don't need a whole lot of DE to do the job. You can use a filter like the HOT magnum by marineland, and just put a few TBSP. of DE before the Micron cartridge for added filtration. If you have a little "light" plumbing skills and an old powerhead or pump, you can make a DIY combo micron/DE filter for under $25. As far as whats better IMO the DE will make the water alot cleaner than micron but is a little more work because you have to clean out the powder. If the micron doesn't do it for you it could be "modified" to a DE filter.

I must say its' been so many years since I put the diatom canister type filter on my aquarium , I'm not sure exactly what did happen, though normally upon turning on the motor on the pump the the diatom earth would slowly deposit a uniform layer of diatom earth on the bag and the water would flow through cleanly without pushing diatomaceious earth through the bag, but it seems most likely the problem happened, when I didn't preshake the diatom earth, so it was well suspended in the water before turning on the pump , and in that case it would flow easily through the bag, though in those days it's possible the bags didn't have the very small mesh that would prevent water from going through an uncoated bag. When the normal suspended stuff deposited, it layers itself so the individual diatoms overlap and since the openings in those tiny shells are so minute , no futher diatom eart could go through. I hope this explains the problem , though it was caused by a stupid error on my part most likely, when I'd forget to shake the powder in the jar with water prior to turning on the pump. I'd guess from looking at some descriptions of other types of filter bags in use now or perhaps even a very long time, that the very fine pores or mesh wouldn't allow that with those types of bags. I'd guess my filter might have been one of the earliest on the market and not yet perfected. It did also have a most disturbing habit of popping the hoses off unexpectedly sometimes , which could make for a major flood.

well then, i just have to make up my mind- an extrememly difficult feat in itself.

woeisme, i grovel at your feet with these diy abilities :)

I used to run a DE filter made for hot-tubs to constantly filter the water in an 80 gallon hexagon tank I had. I used to keep the filter underneath the tank stand and would monitor the pressure of the water in the filter on a gauge that was at the top of the filter. I used to have to clean and re-coat the fins inside the filter about once per month. The impeller on the pump that ran the filter had been modified at a machine shop so the water volume going into the tank wasn't too high and more easily controllable by a valve. I never had a problem using that filter. My fish stayed very healthy and the water in that tank stayed at good ph levels. The tank water was sparklingly clean all the time. I loved it. When the water volume lowered little by little each week I would simply open a valve a bit more to increase the water volume till it was time to clean the filter when I could no longer increase the water volume enough at the valve which took about a month. I had heard not to let any DE get into the tank so I used to use a large plastic tub filled with water when coating the fins with DE. I also designed the inlet pvc piping going in the tank to allow air to mix with the water so I didn't need to aerate the tank with a separate air pump. The filtering system had worked without any problems to speak of and that water was CLEAN and the fish were HEALTHY! I used to keep a goldfish bowl inside the tank where some of the fish used to love to go in it and spend time there! I had oscars back then where it used to be a lot of fun to watch them when they were small.