I have the intex 18 foot pool and I think it would be a waste to add all that more $$ for a swg. We just use BBB and it works great and is easy. This is my second year of the pool and while I appreciate Bens kit, I use the htc $15 kit from walmart, not paper strips here. I follow the advice of the group and absorb and use the info and my pool is just what we need for now. This is a great group of diverse people and they will help anyone who asks nicely. I can't give advice with numbers sorry, but I think you are on the right track. Maybe someone else can comment on the numbers.. Kim