Best way to get to 0 CSI

[hacker]

I've owned a hot tub for about 5 months now and a few weeks ago I refilled the water. Since I've been reading and lurking on the boards over the past few months, I made the switch to BBB. Everything is going well, I think, but I want to know what the best option would be to get as close to 0 CSI from where I'm at now.

The tub is 425 gallons (1600 litres) with a circ pump/ozonator. I have a Taylor 2106 test kit and my most recent numbers are:

pH 7.6
TA 70
CH 100
Borates 50

The tub has a SpaFrog system in it with just a bromine cartridge, no mineral cartridge. My bromine levels are about 3.5-4 ppm between tubs.

With the most recent test settings, the CSI is about -0.24 (we keep it at 102 degrees F).

My pH is stable and doesn't fluctuate. When the TA was higher, the pH would drift up to 8 or higher - not sure how high because the scale only goes to 8. I've been using dry acid to bring the TA down and that seems to have regulated the pH.

Doing some basic calculations, I figured I have some options, but not sure which would be the best....
1) Bring up CH to about 150 which would make the CSI -0.06
2) Bring up the TA to 100 which would make the CSI -0.07 but I would be worried about pH fluctuation
3) A little of both or something else....

Thanks!

 

[linen]

Welcome to tfp, hacker

What is your spa surface?

Why do you want to move csi to 0?

If your spa is not a plaster surface, then you should not need to worry if your csi is negative (or even slightly positive).

 

[hacker]

Thanks for the reply. It's a fiberglass spa. Caldera Geneva to be specific.

I was thinking that the closer to 0 I get, the more balanced it is. Right now, I find I get dry itchy skin after using the tub. It could just be sensitive skin but I was hoping that it was just that I need to get closer to 0.

One other thing I forgot to mention was that I have what feels to be scale on the seats before getting in. It's not much at all and it goes away when the jets turn on. I don't have a ring around the water line on the spa surface though so I don't think it's scale, but I could be wrong.

 

[linen]

I can't speak to bromine much, since I do not use it in my tub. With that said, I doubt chasing csi will solve the itchiness. In my experience, itchiness is typically caused by ph being out of recommended levels.

How does you water look?

When is the last time you drained/refilled?

Since you use the bromine cartidge, from How do I use Bromine in my spa:

The dimethylhydantoin in the tablets seems to have a similar (but not identical) function in a bromine system as CYA does in a chlorine system. It tends to stabilize it but, like CYA, too much is not good.

On a side note...I have had trouble the few times I have soaked in bromine tubs in the past with itchy skin/rashes. Of course I do not have test values for those tubs that caused me problems, so I do not know if they were properly maintained.

 

[hacker]

The tub was drained and cleaned 3 weeks ago and I did a fresh fill using municipal water.

Water is clear and smells fine. When the tub is on, it gets "cloudy", but I think that's just the air in the water that's being moved around. After a minute or so of turning off the jets, it clears again.

I know it's too late for this fill, but for the next fill... Would chlorine cause less irritation? I know that this could be a personal preference as to what bothers each person though...

 

[linen]

The tub was drained and cleaned 3 weeks ago and I did a fresh fill using municipal water.

Next time you may want to try a decontamination. See: the link inside the first post in How to use chlorine in my spa.

I know it's too late for this fill, but for the next fill... Would chlorine cause less irritation? I know that this could be a personal preference as to what bothers each person though...

Again, I can't speak for a properly maintained Bromine tub, but I have had very little problems with my properly maintained chlorine tub.

 

[hacker]

Thanks for your input linen. I did use SwirlAway when switching out the water, but next time I'll follow those decontamination settings.

 

[chem geek]

With a fiberglass spa, don't worry about the CSI -- it can be lower with no problem. The CH level at 120-150 ppm is to prevent foaming. As for itchiness, though it might be pH that is off, it could also be a sensitivity to bromine. Decontaminating the spa at your next refill (use Spa System Flush instead of Swirl Away -- most report better results with the former than with the latter) would help eliminate the possibility of biofilms being the cause.

 

[hacker]

Ok, thanks for your information. I appreciate all the info!