I understand your desire to get rid of algae, but you could be causing more harm than good to your fish by doing so the way you’ve described. First of all, when you clean your filter system (and you should be doing so monthly), make sure you aren’t cleaning whatever part of it contains the “beneficial bacteria” – that which cycles your tank and keeps it healthy for your fish (for instance the sponge media or bio-wheel, depending on the filtration system you’re using). Killing off the bacteria that converts ammonia (fish waste and excess food particles) to nitrites and nitrates can cause ammonia levels to become toxic in a very short time.
Also, while it’s advisable to “vacuum” the substrate (the gravel on the bottom) to remove decaying waste and food, some of the beneficial bacteria is also living in the gravel, so scrubbing it clean is also potentially hazardous to your fishes health.
Make sure you thoroughly rinse anything you’ve soaked in a bleach solution before putting it back in your tank.
The best way to control algae is to prevent it in the first place. There are several things that contribute to excessive algae which are very easy to control. First of all, if your tank is getting too much light (whether from the artificial light from the tank hood or from direct sunlight), either use the hood light less frequently or move the tank out of the sun.
Secondly, if you’re feeding your fish more than once per day (in spite of what the morons at Petco tell you or the fish food manufacturers put on their labels because they want to sell more food), cut back to once a day feedings. Trust me, your fish will not starve to death – in fact, they’ll be MUCH healthier, as will their environment. Also, if you have room enough in your tank for additional fish, get one (or more, if you get schooling fish such as clown loaches) that is/are bottom feeders. They’ll help keep the tank clean by eating the food that falls to the bottom so there’ll be less waste to decompose in the tank.
You could also get fish that are algae eaters. Some of them are actually called algae eaters and others, such as mollies, aren’t considered such, but still enjoy eating it. Don’t make the mistake, though, that adding one or more algae eating fish will eliminate all the blooms (even you couldn’t finish all the food on a buffet!). Apple (or mystery) snails are fun and interesting tank additions, but they also will not keep your tank clean of algae, so don’t mistakenly rely on them, either.
Also, you should be doing 25-30% water changes monthly. Bodies of water in the wild are able to cycle completely, as they’re considered “open” environments. That means fish and food waste creates ammonia, the beneficial bacteria converts it to nitrite, then to nitrate and, in a body such as a lake or a pond, nitrates are then absorbed into the atmosphere. In a closed enviroment, like a fish tank, the cycling process ends with the accumulation of the nitrates. The only way to reduce them is to siphon off some of the water and replace it with nitrate-free water periodically. However, you want to be sure to treat any tap or bottled water before adding it directly into the tank, as it contains harmful chlorines and chloramines. And never change more than 50% of the tank water at a time (and then only under the most dire circumstances), as this can (and will!) cause fish stress which can kill them.
Here’s a web page that has some good information on treating algae: http://faq.thekrib.com/algae.html
Good luck – I hope you can get it all under control!
Poor thing.