anemone and sarcophyton

I've never heard of leathers being toxic--and can attest that I have several leathers in with very healthy pulsing xenia.

What lights do you have? Feeding? Tank location? While I discourage people from getting an anenome for their clowns--the reverse is not true. Wild anenomes are much healthier with a resident population of clowns, and I think the same may hold true for captives. You may want to find a compatible clown for your anenome, and make sure it is fed (silversides, meaty foods!) about every 2-4 days.

I'd say the lighting in most likely the problem, but it could be other water quality issues as well. What are your tank parameters (ammonia, nitrite, nitrate, specific gravity)? How often do you do water changes? Do you have a protien skimmer?

Start saving now to upgrade lights to at least power compacts--check www.hellolights.com for very reasonably priced PC hoods with built in fans.

RO (reverse osmosis) water is the same as distilled water (its basically 100% pure water with no contaminates or disolved minerals), although treated tap water is basically the same thing (just let it sit for a couple days) Also test the tap water for nitrates and other stuff.

leather toxicity

Although this may not be your problem, many soft corals put out toxins for defense/offense. Sarcophyton and sinularia are two of of the worst. To keep mine from poisoning the other corals in the tank, I use carbon, which gets changed whenever the montipora gets pouty.

Nonetheless, I agree with OrionGirl about light being the likely culprit. 20 watts over a 29 gallon tank is not really enough. You might think of doing a retrofit with a kit from Aquarium Hobbyist if you can't afford a new hood.

If I understand correctly, it sounds like you are using different salt mixes. While I am not chauvinistic about brands, I have noticed that people often have negative consequences when they change salt mixes. They are all slightly different, and livestock often have trouble if they are subjected to alterations in tank chemistry. My suggestion is to stick with one brand.

One problem with regular tap water is the possibility of contaminants. Mine has nitrate, and I worry about copper. Reverse-osmosis water is subjected to several levels of filtration to get rid of most contaminants, including NO3 and metals. You might just dechlorinate your water and run some tests to see what's in it. Marine tests will work on fresh water.

I use tap water and ours is hard water with no nitrates and no copper, but to be safe i still add ammonia remover and dechlorinating chemicals to remove any toxic metals and then let the water sit for 3 or 4 days. I only have a chocolate chip starfish in my 15gl aquarium and it does great.

I invested in an RO machine a few years ago after buying RO water was gettting costly. RO water is the best for drinking and cooking and some people use it just for making better coffee.
My RO is in the basement and plummed to my kitchen sink. I got tired of adding water to the fish tank so I plummed the pressure line also to a float in my fish tank.