Wow! This is a very well written article. There are so many helpful leads in this article. I wish I would have been able to read this when I first started with my goldies.
I've had my tank for a little over a year and have done a lot of trouble shooting. From personal experience, I agree with a lot of what has been said.
I switched to sand substrate about 6 months ago and it has made a world of difference. Like mentioned in the original article, the sand tends to keep the waste from settling down into the substrate. I monitor the tank quite a bit and I can never really notice the waste. It gets moved up into the water column and then pulled through the filter, making a world of difference in the overall appearnce and cleanliness of the tank. Also, I had a problem with algae growing and attaching to the original gravel substrate, making it very hard to keep a clean looking tank. After 6 months, there's no algae on the sand. The sand is actually quite easy to clean. I turn my net upside down and stir up the bottom a bit to release the waste into the water column just before using my gravel vac to clean the waste out of the tank for water changes. You can even run the gravel vac over the surface of the sand and suck up a very minimal amount of sand while still sucking up the waste.
I haven't noticed any adverse reactions from the goldies since I've put sand into the tank. As mentioned in the original article, the goldies tend to sift through it quite a bit. It doesn't look like they try to swallow any of it. They simply take a small bit in their mouth in search of food then just blow it out. A week after doing a water change, there's a bunch of little divets in the sandy bottom from the goldies sifting through the sand. I even have one goldie that likes to nap right down on top of the sand. He's found his own little place with very little current where he can put his belly down on the sand and nap.
I never had any problems with sharp decorations but read plenty of articles where they have caused problems. I got rid of my "fantasy" 'scape and replaced it with sand and smooth sandstone (I think). The sandstone looks great with the nearly white sand black back ground. There's no sharp corners and I haven't noticed any detrimental effects.
Food. My goodness, food can be a complicated thing for new hobbyist to figure out. My aquarium setup came with flakes, so I naturally started using them and continued to do so. After a few weeks I noticed my black moor was having buoyancy problems. After doing some research I decided to go with slow sinking pellets. LIFE SAVER! They're small so you can use them with your small goldies, and they will float for a brief amount of time so your goldies can track them down and then get a hold of them before they sink too far away. I tried pre-soaking the flakes and that just made a mess since it can be difficult to judge how many flakes to add. With the pellets, I can monitor who gets how much and I can also make sure there isn't a lot of wasted food that breaks up and sinks to the bottom, leading to decreased water quality. Once a single goldie gets a mouth full of 2-3 pellets, he (or she) isn't as interested in the other food going into the tank, allowing the others to get their share.
If you did manage to buy a general setup like mine, you probably were given the tank, stand, hood, light, and some sort of filtration device. Mine came with a bio-wheel power filter. When I changed over to a sand substrate, I also decided to double up on filtration. My power filter came with an extra media slot, so I bought extra cartridges and put two in at a time. I'm guilty of going nearly a month and a half at one (and I repeat ONE) time without doing a water change and my power filter never once overflowed. If you clean your filters every two weeks (for me, every other water change) you shouldn't ever have problems with the water flowing past the filters and back into the tank. Ideally, a cannister filter would be best, but we don't always start out with that option.
Re-read the original article again. It's a wealth of information that has proven to be quite true for myself over the last 14 months. Thanks again