Spa Newbie My Experience And Csi Question

[Bullfrog]

I am a newbie when it comes to spa chemicals and balance but have been doing a lot of reading on this great forum and that has helped tremendously. I have a Master Spa with the Eco-Pur mineral filter. It is a 410 gallon spa that I keep just about an inch above the minimum level so that the neck/shoulder seat hits my wife just right without the water level being too high. I understand from this site that the true volume of water in the spa will be much less, I have been using 350 gallons in the pool calculator for my chemicals, although I don't really know. I am going to measure it on next fill.

I started out using Dichlor and MPS, after doing the first weekly shock using MPS I started getting an itchy back. It really didn't seem like a bacterial issue, because it really wan't a rash with bumps or anything like that, it just itched a lot and got splotchy red when I scratched and no one else in the family had the itchies. Anyway after reading a ton of posts on this site, I decided that I was going to switch to the bleach method and stop using MPS. I got a Taylor test kit and found my CYA was high at 60. So I did a half drain/fill a couple weeks ago to bring that down, rebalanced, added Borates, then started using bleach. My itchy back has gone away, water is clear, no foaming, no odor, my chemicals appear to be pretty stable.

After the rebalance my PH was 7.6 and slowly creeped up over a couple weeks to 7.8 which I understand is common using bleach and with aeration. So I added some Dry Acid to bring that down a little and I assume I'll likely need to do that every couple weeks. Other than that it seems that everything is just steady and easy to maintain by just adding the bleach daily and then dry acid every once in a while.

So my question is how important is CSI? The CSI for my current numbers is -.4. Should I be concerned with trying to get that closer to 0? Should I adjust anything or should I just be a happy clam with the way things are going, keep everything as is and just maintain with bleach and dry acid.

My current numbers:

FCL 3.5

CC 1.0

PH 7.7

ALK 50

CH 110

CYA 30

Borate ~50

Temp 100

An observation on sanitation, according to the bather load information I've read here, I am using about half the bleach that I would expect based on the 7ppm per person/hour guideline. We use the spa frequently about 5 nights a week, load is anywhere from 1 person for 15 minutes up to 2 person/hours. I put in about 3ppm on nights when it's not used and adjust that upwards based on bather load up to 7ppm for a 2 person/hours and end up with between .5 to 2 ppm for the next soak. I am still fine tuning the ratios of bleach and usage so that I end up with a small residual prior to the soak. At this point I assume that the ozonator and maybe the mineral filter are reducing the chlorine demand.

Thank you all for hosting this site, contributing to the forum, and helping out noobs like me. I was lost and frustrated with the information in the manual and those stupid test strips. The information here has made everything much easier and I am a lot less stressed out over the chemicals and can just enjoy using the tub.