Thank you very much for taking the time to give me such detailed feedback. I made it a point to immediately purchase the Taylor K-2006 test kit, and read many more posts on these forums.
Before my test kit arrived I purchased a product called a Clarifier from my local spa dealer. After foaming like crazy and leaving a residue at the water line it really cleared up the water. The product didn't have an ingredients list, which I found interesting. Despite how well it worked its effects only seemed to last for a week or so. I had been using a combination of Dichlor and MPS shock. The spa dealer recommended that I add 1/2 teaspoon Dichlor per person and 1 TBS MPS after every use, and mentioned nothing about sanitation levels in between soaks.
After reading more of the posts and getting more accurate results from the proper test kit I was able to figure out that a few things: First, I was chasing pH changes around way too much. I suspect that my improper use of dichlor and the timing of my testing was causing what I perceived as wild pH fluctuations. Second, the use of MPS shock (and possibly the clarifier) was giving me very high combined chlorine readings up to 5.5ppm at times. Third, I realized I was taking a horribly wrong approach to sanitation.
For the last two weeks my water balance has been such: Volume: 500 gallons, Temp: 99F, CH: 125ppm, TA: 70ppm, pH 7.5, CYA: 30ppm
Sanitation on the other hand has been interesting. I've been using the dichlor/bleach method and I'm very happy with my sparkling clear water but my Chlorine demand seems crazy. For the last week (5 nights in a row actually) I have been shocking (with 6% bleach since my CYA is in range) to 10ppm every night and in less than 24 hours my FC is less than 1ppm! The CC is right were it needs to be at 0.2ppm or less. My Hot Springs Tri-X filters are less than 6 months old and they've been cleaned once. I have two extra that I rotate through. It's only my wife and I and a 3 year old that use the tub maybe 4 times a week once a day for less than one 1 hour. The tub does have an ozone system; I'm considering having it disabled assuming it's raising my CD. I have not added any borax yet. I think I'm just being cheap about buying the amount of acid I'd need to balance the pH back into range.
Finally, the only other minor concern I have at the moment is the presence of small white flakes in the water, about eraser head sized. They are silky in texture and break down promptly if you squeeze them between your fingers. They have no discernible odor and are most abundant around the filters, very few are found in the actual tub.
So my questions would be: What do think about my Chlorine Demand? Do these silly white flakes mean anything, given that my water is nice and clear? Should I make it a point to add a full 50ppm Borates? And last, do you recommend any particular filter cleaning product/process?
Thank you again! This forum is a life saver!