salt water corals

Question
This is a follow up answer.I have four 65 watt florecent lights I had my aquarium for a little over a year now.The size is 125 gallon 5 feet long by 23 inches high by 18 inches width.I have a blue tang,yellow tang,two green coromus,two clown,a purple fire fish,two diamond sleeper gobies and a coral beauty.
Thank you
Ken  
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The text above is a follow-up to ...

-----Question-----
I was having problems with the nitrate level so I had to do some water changes I still don't have the nitrate level biologically balanced so I've been doing 20 gallon water changes every week.I have a Bubble coral and a Hammer coral shrinking back into there rock they are spaced away from each other.I'm I doing something wrong maybe too much water change at once?
-----Answer-----
It's a tough situation. You want pristine water quality for your corals and want your nitrate level to fall by doing water changes which does not stabilize for a day or two. Mix your "water change" water about two days in advance with both a heater and airstone curing the water before adding to tank. What type of lighting do you have,fish do you have and size tank you have? Adding amquel plus to your change water may help, also. There are some other remedies you can try to help eliminate nitrates. Go to about.com. Click on hobbies and games, next page click on saltwater aquariums. You will be at a great site where you can find DIY plans on a denitrifyer, as well as other suggestions. Gerry.

Answer
The lighting may be a problem for your corals. Some require very strong lighting and certain color temperature to thrive. They are different and have different requirements. Corals are not my specialty and you need advice beyond my expertise. Go to the website I previously told you about and you should find some valuable info on corals, as well. They are very delicate and very beautiful.