Red Slime algae is really bacteria (cyanobacteria). This is not caused by phosphates. The natural way of ridding the tank of this is to first skim off as much as you can. Then do a 50% water change. Several smaller water changes will not work. You will never get the bacteria down low enough to catch up.. I expect the tank is less that a yr old and I has not matured all the way yet.. After the water change cut lights back to 4hrs a day for 4-5days then start bringing the lights up 1hr a day till back to normal. Also cut back on feeding some. Another suggestion is make sure you have a deep sand bed of at least 3-4in. This will let enough good bacteria grow to help prevent this problem..If you just cannot wait You can use a product called chemi-clean by boyd enterproses, inc... you can do a search on the internet for thier phone # or where to purchase. After using wait 2days then do the water change...Their are no short cuts...good luck...
