Novice fish parents

Question
Our 28 gallon tank has been set up about 2 months, but we used some gravel and some plants from another established tank given to us.  So we never had huge problems with ammonia, nitrites, etc.  Our water has been testing great for about 4 weeks.  
We have lots of brown algae, and cloudy water again.  I understand we should do frequent water changes.  What sort of conditioner/dechlorinater would you suggest for very hard tap water?  We did a 50 percent water change last week, added AquaNova and Easy Balance with Nitraban and lost 4 fish the next day.  
We have a 5 inch plecostamus along with 4 neon tetras, a black skirted tetra, a balloon molly, a dalmation molly and 3 other small tetras.  Is the plecostamus too big and causing too much waste?  We love him but a pet shop said we could trade him for a smaller one.  Any suggestions for us?

Answer
Hi Tammy;

I think it's all part of the break-in process really. It just hasn't had time to be fully balanced yet. Even with using some gravel and plants from an established tank, the bacteria colonies haven't grown enough in the filter to handle all the waste that all the fish make. The fish losses were just from having too many fish all at once for a new tank.

You really only need the Aquasafe and use it only when you make a water change. I wouldn't waste money on the other stuff. They claim to keep you from having to do water changes very often. Don't fall for it. There is no healthy substitute for good weekly maintenance. I think a 50% change was just too much for the fish. It shocked them. Even if the temperature was correct, they still may not tolerate it very well. Try not to change more than 25% at a time. If there is a serious problem you can change 25% daily until things get better. It will get things back in order slowly without harming the fish. Once it is doing okay, do the water changes weekly with a gravel vacuuming every couple of weeks.

You could certainly trade in the pleco. He may get bigger and make even more waste as time goes by. Plecos can even be responsible for killing smaller fish. They do it at night while the others are resting near the bottom. When you shop for a new kind, be sure to avoid "chinese algae eaters". They get nasty as they get bigger and will start attacking your others. Three or four Otocinclus cats (they get only an inch long) or a smaller type of pleco such as bristlenose, candystripe or rubbernose would be better.(those types of pleco each get a maximum about 5 inches) Here are links to profiles of some;

Otocinclus;
http://www.fishpondinfo.com/otto.htm
http://www.aqualandpetsplus.com/Catfish,%20Otocinclus.htm

Bristlenose;
http://www.fishprofiles.com/files/profiles/640.htm

Rubbernose;
http://www.fishprofiles.com/files/profiles/331.htm

Candy Stripe (aka; clown pleco);
http://www.piranha-info.com/default.php?lang=en&id=L015

Hopefully you can find these guys where you live. I hope everything gets better soon...

At Your Service;
Chris Robbins