Not an expert with lighting but don't think T5's are strong enough. We never had any luck wiht hard corals under them. We invested in overhead halide lights which are far better for all coral, in my opinion.
I have an RO kit set up in my back garden. It links to my ouside tap and goes in to a plastic water butt (when I need to make more RO water). We have our own RO water on tap at all times! Initial outlay not cheap but saves a fortune in long run and more convenient! Make sure the butt is on a stand with a tap and has a sealed lid. The RO kit will need to be put inside in cold weather though! We have "grown our own" RO water for 5 years using this method and have never had a problem.Swear by it. (Only just popping in today so PM me if you want an answer for anything).
I would agree- leave them. There seems to be a myth about having to remove them in a panic. In my tank I have inverts, corals & fish and I have never removed a single bristleworm and have hundreds probably. They are part of the family so leave them be...they have not bothered anything else.
Overall exceptions or not, most anenomes need good lighting and mature conditions to survive. I do not specifically feed mine, but do add invert food and microplankton in with the fish food. The anenomes I bought inside the first year died and the ones I have added after that time, and now coming in to my 3rd year (I think) are fine. I have also cahgned my ligths from T5 to MH in that time.
I would say it is best to advise new starters along the lines of sufficient lighting and tank maturity for those who want to keep anenomes....they would stand a better chance from the offset, even though that doesn't rule out the success of others in different circumstances...
I would agree with the above, and one thing to remember, if you do frequent water changes you are replenishing the natural elements. If you leave the water for longer that is when the elements and minerals get depleted and need adding.All in ones are better and safer.
I didn't get to do a water change for 5 days and the remaining fish recovered over the first day or so after the nightmare so it shows it was something drifting in to the water and then being removed via the filters etc...shows how quickly things can fail and also recover. I have done a routine water change now but it all happened too quickly to do a change at the time...boy my tank looks so empty. We are still trying to sell our house and moving the tank then, will be a nightmare,so at least fewer fish will be easier to relocate...
I would say one tang in that size tank would be more than enough on the tang front, but to add to the comments for general opinions re tangs, yellow tangs can live fine with various other tangs eg regal Tangs & powder Blues. The key is having enough space for them....one general rule is not to have 2 of the same shape. Strange that that may seem as they do not have a mirror to distinguish themselves from eachother, but it is a theory that tends to work! Saying that you can buy 2 or 3 yellows and they will be happy in a shoal. If you had a yellow and a powder and then wanted to add another , that would be the big no! My Regal and yellow lived fine in our large tank, but the space is the key to them getting on...enough room to have their own territory and swim away when they need to.Also Surgeoinfish (tangs) are prone to whitespot especially if stressed out. I found the only way to overcome that was to buy one as a tiny baby eg size of a 50p, and watch him grow. The babies seem more hardy to me?