angeldees' aquarium tips
*Water Changes*
!!!*NEVER use soap*!!!
Ok, depending on the size of your tank- the type of fish that you have,  and how many will be the determining factor here.
However- I will give you my stats- and my routine, and you can sorta get an idea from there.

On all my tanks- I clean them weekly. doing a 50% water change, and in some cases (my gold fish tank) I do more- a 90% water change.
This is how I do it. Here is a list of items that you will *need*

1- a gravel vacuum.
2- a bucket for the dirty water.
3- a water conditioner ( *
AQUARIUM PHARAMACEUTICALS, INC- TAP WATER CONDITIONER ) is what  I use, but most water conditioners that remove Chlorine, and neutralize Chloramines will do.
4-a fish only sponge scrubbie (or you can do like me, and use plain paper towels!)
5- clean water.~

First I turn off my pumps/filters- and heaters. then I use the gravel vacuum, put it down into the gravel- it will pull out all the yukky stuff. don't worry about the gravel, it will fall back to the bottom.
Please do not skimp on the vacuuming of the gravel- this is very important in maintaining your aquarium.
insodoing as you vacuum, the water level will drop.
When you have reached the desired % amount, take your scrubbie, or paper towels.. and wipe down the sides of the glass. in some cases you may want to leave the back glass with a bit of the algae, some fish need this algae to thrive (mollies)  also be very careful if you decide to use a scrubbie pad on a hex tank- as it may scratch it.
at this time you may want to wash off any decorations and plants, with the tank water, or I just use fresh water from the tap.
I take out my filter pads, and wash them in tap water - this is done weekly- once a month I do a complete breakdown of the filter and wash all the goo from the intake, the inside of the pump, and the water down pour- a toothbrush comes in handy for this.
*note* please be aware that some aquarist are against using clean tap water for cleaning any parts of the tank (it may destroy beneficial bacteria in your tank) however- I personally have had no problems with this method- I have had my tanks set up now for over a year.. and I do this weekly.
***I do not recommend this method on a *new tank set up* just because I didn't start doing this till after my tanks had already cycled***
After you have wiped down your aquarium glass, sides, rocks, and such... put in your the recommended amount of water conditioner,(for your size tank) and fill your aquarium back up- make sure you have the new water going in the tank as close to the same temperature as the tank water itself. don't want to shock the fish!
wipe up any excess water, turn back on your filter, and heater.- and viola! your done!((:
Never, never, ever use soap on anything that will come into contact with your fish, or aqurium.or items that you will use in the tank!
If you have a nasty aqurium, use water, and a scrubbie- OR there are things available on the market, *fish safe* to help clean those hard to clean items- however prevention is the key here- if you clean your tank, filters, plastic plants, rocks, weekly, or at least monthly, you will not have a problem.
*Gravel,Pebbles, Sand,Rocks*
Gravel, Pebbles, sand, rocks??? which is the best substrate for my aquarium??? which is the prettiest!

Ok, my experience here has been this:
Go with the substrate that *fits* your fish!
For example--->> Corydoras (cory cats- cat fish) are bottom dwellers, they scurry around the bottom for bits and pieces... bottom feeders.
If you have 'gravel' as your substrate- after a while, they will have scratched up bellies, and it can tear off their barbells, leaving them straggly. )):
Sand is a better choice for catfish- OR smooth rounded pebbles.

Goldfish get very large, and have a tendency to suck rocks up in their mouths, so getting a larger rounded rock/ stones would be a better choice for them. ( I have had to use tweezers 3 times to get a rock out of my goldfish's mouth, it was no fun! and really scared me!) I now use the decorative large glass rocks in their tank now.

My experience is: the cheap small gravel is usually not a good choice, unless you have very small fish that the gravel cannot fit into their mouths.
*pebbles* is the safest- and it looks so nice and natural too!---> *remember* it is best to keep the fish surrounded by *natural* looking scapes, make them feel at home, I have seen people use pink or purple substrate in a tank- knowing good and well, most fish do not have red or purple in their own environment. unless of course you have reef tanks- and thats another story((:
***During each water change- it is wise to use Aquri-Sol, by: Aquarium Products- It prevents ICK, (For Fresh Water Fish ONLY)-----Safe For Plants- (Use 12 Drops per 10 Gallons of water)
This is great stuff*** a small bottle will last you a long time.---->> also some aqurium salt is great for goldfish, i use it every other or every third water change.