Please help with this!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Beverly]

Here is what I would do:

1. Step up your water changes to weekly 15% of the total water volume. However, now that you have a pretty good cyano problem, I would probably do a couple of 30-40% water changes to help lower nutrient levels. Great that you are using RO

2. Adding some macroalgae will help utilize the nutrients in your tank. Depending on the species of macroalgae, your tangs may eat it too.

3. I would agree that upgrading your skimmer would help. However, we don't skim our tanks, but keep the number of fish to a minimum to reduce bioload and nutrient production.

4. If you haven't changed your lights in over a year, doing so will improve the quality of light in your tank and may help reduce the cyano. However, changing your lighting alone will not solve your cyano problems.

5. Get a magnesium test kit and start using it weekly until you have a sound understanding of the magnesium needs of your particular system. Magnesium is as important to overall water chemistry as is alkalinity and calcium. Here are some articles on water chemistry:

Aquarium System Volume Calculator:

http://home.comcast.net/~jdieck1/volcalc.html

The Reef Chemistry Calculator:

http://home.comcast.net/~jdieck1/chem_calc3.html

Magnesium in Reef Aquaria:

http://www.advancedaquarist.com/issues/oct2003/chem.htm

Solving Calcium and Alkalinity Problems:

http://www.advancedaquarist.com/issues/nov2002/chem.htm

HTH