Haddoni is a lot more sensitive than a BTA. I would not recommend one for your tank.
For now, I would recommend getting water parameters to a decent level for your end goal of what you want to keep, focus on getting the tank to be super stable with those parameters, and get into a good routine of proper husbandry (not saying you do not have any).
Once you start to see your tank on autopilot, things growing well, testing coming up the same values over and over during a long period of time, then I would suggest you try another BTA.
Biggest thing for nems is stability and a decent set of parameters.
For example on the parameters (this does not always hold true and is only from my personal experience)
When keeping an all anemone tank (14+ different types) I kept my tank around the below.
Salinity - 1.026 consistent. No more than a .001 fluctuation in a day
Alk - 8-9 with no more than a .2 swing per day
Calcium - 420-430 (not really a big deal with nems, but has affects on other things related to the nems in terms of water quality)
Mag - 1350-1400
NO3 - 5
PO4 - .08-.1
PH - 7.8 or higher (if my PH ever got below 7.8, they would shrink up and look a little ticked off)
All of the numbers above were consistent and never wandered around much. I also ran carbon and dosed the tank with all/cal/mag and did not do water changes, excluding where I would replace water here or there from bagging up nem splits, or from where water was removed when cleaning the skimmer.
I also maintained a tank that was smaller and mostly BTA, RFA and LTA doing the same as above, except it got a 10% water change a week. I just used water that matched my current params, so I did not change anything but the nitrate and po4 (WC was to lower these).
Again, trick is stability and good water. Not clean, as in sterile, water, but at least traces of nutrients. And finally having the setup be aged enough so "You" know how the tank reacts to things and know how to manage those things.
