Lighting, flow and stability are the three things to look at for BTAs. Typically when anemones move it is because they are unhappy with the conditions of their environment. They like to be able to anchor their foot in a crevice and extend their oral disc into a well lit area with moderate to heavy indirect flow. As for stability calc, alk and mag should be within acceptable ranges and should remain constant as shifts in these or if they are out of normal ranges will cause pH to swing which will stress out the anemone. As for nitrates, large swings in nitrates tend to be as bad, if not worse, for anemones than just simple high nitrates (high are still bad though). The 6 month rule is a rather arbitrary line but is used mostly to describe the point at which a reefer is typically comfortable maintaining parameters after the initial cycling process which can cause swings.
You really should begin testing alk, calc, mag and nitrate on a regular basis in general as it will greatly enhance your ability to maintain a successful reef. Typical acceptable ranges are:
Calcium: 380-450 (try to pick a number and stay with in plus or minus 20ppm of that, if 400ppm then never lower than 380 or higher than 420)
Alkalinity: 7-11 (pick a number and stay within plus or minus .4dkh of it)
Magnesium: 1250-1400 (1300 is the number I like, magnesium is fairly forgiving of swings but staying right around 1300 will help a considerable amount)
Nitrate: 0-5 (as high as 25 can be tolerated by most inverts but the tank is very unlikely to thrive above 5)
Phosphate: 0-.1 (this will be more important the further you get into the hobby but for new hobbiests this one is tricky and stripping a tank with gfo without monitoring can have negative effects)
Also keep in mind that alk and calc work together and if one is higher the other should be too.
As for lighting a 4 bulb t5 fixture over a standard depth tank is the bare minimum for lighting a BTA if you are new to the hobby. People have kept them under power compacts or low quality LEDs that push less light than a 4 bulb t5, but typically these are people with established tanks and stable conditions as well as several years experience. When new to the hobby it is best to shoot for being over the recommended minimum rather than the anecdotal minimum. For LED fixtures I typically recommend a 3 watt per gallon rule for anemones just as a safe guide, and the LEDs should be dimmable whether by knob or controller. They wont need to be run at 100% on all channels but the wattage assures that you have enough penetration and spread, plus it eliminates fixtures like the fluval and marineland which really just wont get the job done for anything more than softies.
As for flow, there needs to be a minimum of two sources of flow to avoid detritus buildups that are a nitrate disaster waiting to happen and multiple flow sources allow you to better mix the flow in the tank to achieve that indirect stream or wave that BTAs prefer. I have always had the best luck with wavemakers for nems but they are not necessary. If you have multiple powerheads you can position them so that they create channels of flow in the tank (the old point one down and to the back with the other up and to the front trick) that allow for a strong current without the powerhead directly blasting the nem (also keeps the flow from hitting the nems foot which can cause them to move).
No matter if you want to post numbers and get more advice or not I would strongly implore you to begin testing alk, calc, mag and nitrate ASAP. If you have questions about your lighting and flow, post the specs on your lighting and pump equipment, tank dimensions and a full tank shot and we will see if we cant help you out with that as well.