Phosphates or no, you can't manage what you can't measure. You need reliable numbers for your pool. Without them, no one can make any reasonable suggestion as to what your pool needs.
Many people in the pool industry believe that complex chemicals are necessary to manage a pool, but essentially it boils down to maintaining a proper sanitizer, and a pH range where the sanitizer, the swimmers, and the equipment can live comfortably.
Chlorine is generally the best sanitizer/oxidizer. While it needs to be stabilized against UV loss, too much stabilizer 'locks away' more available sanitizer, and requires higher chlorine levels. Dichlor and trichlor are convenient forms of chlorine, but constantly add stabilizer. Cal-Hypo is another convenient source of chlorine, but adds calcium and can be hazardous if not stored and handled properly. If you maintain your pool using these forms of chlorine, over time (and less time than you think) your stabilizer and/or calcium levels will rise to a point where there are other problems. In the case of stabilizer, that problem often manifests itself as an algae bloom. When this happens, the pool guys will then point you to other chemicals to correct the problem, like algaecides with copper, and then you will need sequestering agents to manage the copper, then you need floculants to handle the sequestered metals.etc. It becomes much like the nursery ryhme about
*the Old Woman who swallowed a Fly. These days, the magic bullet seems to be phosphate management. If they can't keep the algae at bay using their regular course of treatments, they'll go after the algae's food source.
What they do not address is that the chlorine, at normal levels, is no longer capable of killing the algae because of the high stabilizer level. And if it cannot kill algae, how certain can you be that it can kill other nasties, like bacteria and viruses?
The only reasonable source of chlorine which avoids these side effects is liquid chlorine - sodium hypochlorite - which is available as 'liquid shock', or more readily, plain old laundry bleach. Many pool stores will scoff at bleach, but most of them also sell liquid chlorine, and it's the same chemical.
For us, the bottom line is that the bulk of the expensive pool store chemicals are simply not needed if you manage your pool with liquid chlorine and some simple pH adjusting chems like baking soda and muriatic acid.
However, all that said, there is nothing we can tell you unless we know what the situation is in your pool, and that requires that we know the levels of chlorine, stabilizer (CYA), pH, and TA, what kind of sanitizer you are using, and anything notable about the water itself.
Do yourself a big favor and get at least a small test kit at Wal-Mart, or even take a sample to a pool store for a reading, but get the numbers, and post them here.
* An amusing children's rhyme about a lady who swallowed a fly, then a spider to get rid of the fly, then a bird to catch the spider, then a cat... well, you can find it here:
http://www.poppyfields.net/poppy/songs/oldwoman.html or from a Google search.