TFC or HiS/Full Size or Bare Bone???

[fishfood]

I'm still trying to find out what is necessary in an RO system. I've been to the Kent Web page and read up on all of the units.
I'm looking for people who have used any of these units or someone who may have used more than one and can tell me which they liked better.
I was looking at a bare bone HiS but don't want to have to pay $100 for replacement filters because the bb doesn't have all the prefilters. I've also been looking at the TFC full size and seems like my best bet, or could i just get away with a bare bone TFC?
Can anyone give me some info on these units?

 

[tacks]

Before you choose a unit, you need to get your tap water tested so that you know what you need to filter out. Depending on where you live and the quality of your tap water will determine which unit is best for you. Hope this helps and Good Luck!

 

[fishfood]

Yea I was going to get the water report from the county. I know that my main problem is with phosphate. I have had high phosphate for a while now. I've been using phosguard to reduce it but can't. I run a canister filter which feed the protien skimmer. The canister is where i put the phosguard and two layers of foam. Cleaned weekly.
The tank has been without fish for the past week so no feeding and i have done a water change in that time and the phosphate is still high (lone surviving fish is in a hospital tank recovering from ick). We have been using the RO water from the lfs but it has also had high phosphate. My girlfriend works there and told them the phosphate is high and they changed the filters but it is still high???? I'd rather buy my own so when i set up my 75 in the next month or so i don't have to get that much water from them and won't have to transport that much water for top offs.
I am still curious as to bare bone vs full size. If you go bare bone than you are running the chance of the filter media having to be replace more often??? Are there any other benefits to full size or not?