I don't think sand would work well with an ugf because it would continue to get sucked in through the plates. You can use play sand or any of the sands normally sold for aquarium use. I think I would shy away from the sand used for reptiles.
I was wondering about that too, lokky. Sand is pretty in pictures, but is it hard to keep the water clear if using sand? Is there a purpose other than appearance for using sand (like would my pleco prefer it because it is soft)? and on the UG filters (one came with the used tank I just got) is it better to use gravel or rocks? thanks anyone for your advice... Denise
I think a UG filter would get clogged a lot with sand particles - something you wouldn't want. I personally don't like UG filters at all - I never could grasp how a UG filter can be effective. Imagine all the uneaten food and wastes on a tank's bottom clogging the UG filter. It seems so messy to me.
I have only read about UG filters and don't remember well how they work. All I know is that the UG filter is positioned on the bottom of a tank (I think it's the size of the bottom of a tank). You put gravel over it. And it sucks the water in presumably through filter media. Of course, the water has to go through the gravel first, and through all the wastes that might have accumulated - which is why I don't like this filter.
As for a power filter (the external one), it is a filter that is a box. You hang the box on your tank's wall (outside the tank, not inside). There is an intake tube through which the water flows into the filter, it goes through the filter media, and then back to the tank. There are also internal power filters which I am not familiar with - except for a sponge filter. A sponge filter is basically a sponge through which the water is filtered - it is positioned inside the tank.
A canister filter is also a box, but you don't hang it on your tank's wall. It stands under the tank and it has 2 tubes: one outflow and one intake tube. The intake tube is where the water comes in to the filter, then it goes through the filter media, and back to the tank through the outflow tube.
It depends on the size of your tank, on the fish that you have, whether you have live plants, et cetera. The following is only a general suggestion and my personal point of view. I personally would use an external power filter in tanks 10 - 65 gallons in volume, and a canister filter in tanks 75 gallons and up. It is of course up to you which filter you'll choose because - as I have said - you may have totally different requirements from mine (i.e. different fish, tank size, etc ...).
I like external power filters for their ease of use and good performance on small- to medium- sized tanks. In my 30 gallon tank I have an external power filter Aqua Clear and I love it. It is durable and it filters the water very well. It also has a lot of media allowing plenty of space for beneficial bacteria. It ensures no water bypasses filter media, thus increasing filtering capacity. I think it's a great filter. Other external filters may be great as well - I myself only have experience with Tetra Whisper and Aqua Clear (I prefer Aqua Clear over Tetra Whisper).
The reason I'd recommend a canister filter on tanks 75 gallons and up is that they have a lot of media to allow the growth of bacteria, they don't need to be cleaned as often as all other filters, and they allow better water circulation in a tank - and a large tank certainly needs good water circulation so that no water is left static and becoming stagnant. But what you can also do in tanks 75 gallons and up, is use 2 power filters on each side of a tank, instead of one canister filter. OR ... you can even have 2 canister filters on large tanks.
It really depends on what you need, how many fish you have (thus it depends on the bioload: how much waste, etc ...), whether you have live plants, and many other factors.
You're welcome. I don't know what power filters are available for 8 gallon tanks, but what you want is a filter that pumps 10 times the volume of your tank. In your case, a filter that pumps 80 gallons per hour. You could get one that pumps 100 gallons per hour as well. There are Aqua Clear filters available for smaller tanks like yours - Aqua Clear 20 would be good for you; it pumps 100 gph. Whisper Tetra 10 would be good for your 8 gallon tank as well. However, if you could choose between the two, I'd recommend Aqua Clear over Whisper Tetra. There are also many more filter brands to choose from. I only described to you those that I have experience with. But from what I know, Aqua Clears are liked by many people and are proved to be very good.
I removed an UGF from my 20 gallon tank earlier this year. I replaced it with an Aqua Clear 50 and have been very pleased with it. I've since acquired a 55 gallon and 10 gallon tanks which both have Aqua Clears running (2 70's on the 55 and a 20 on the 10). The Aqua Clear 20 would work great on your tank.
As for sand causing cloudiness in the water, I haven't had any problems, my water's still crystal clear. My pleco loves to excavate it and my green terrors like to play in it
As for filters, I had a UGF in my 10G and it was worthless. Aqua Clear power filters work very well.