Question about adding chemicals..

[f6487]

I've had my Hot Springs Flair for about three weeks now.  We have been in it every day and some days twice a day.  From what I can tell my water is crystal clear.  Here's how I have been treating my water and maybe someone could chime in to tell me if I'm on the right track.

At least once a day either before we soak or after we soak I add about 1.5 TBS of MPS Non Chlorine Oxidizer.  Sometimes a little extra if we have been in the tub more than twice a day.

Currently I have been doing my test strip once a week.  Each time I do the test strip the only reading that is low is the Chlorine level.  So I've been adding 1.5 TBS of my Chlorine granules once a week and that brings my Chlorine level on the test strip right back to the shade of purple that falls in the ok range.  My Alkalinity and PH levels have been almost perfect and I have only adjusted them down a touch once. 

My question is should I do a test strip more than once a week and is it possible that I could add chlorine like every three or four days vs waiting to the seventh day.

I'm just learning how to do all this and I feel like I have a pretty good handle on it so far.  Based on the clarity of my water.  Isn't cloudy and doesn't smell overly chlorinated.

How does Chlorine work.  If you start the week with the perfect amount of chlorine does it lose it's potency and weaken?  Does the hot water break down the strength of the chlorine requiring you to add more on a weekly basis depending on your usage.

Thanks guys.. Appreciate any feedback..

[Tman122]

I have found that assuming diclor for your chlorine source 1-2 PPM drop per day is typical if you use it everyday. You are likely consuming even more. To be safe I would drive it up to 2-3 each day if you use it.

[chem geek]

There is a certain amount of oxidizer consumed from bather load.  A very rough rule-of-thumb for a hot spa (104ºF) with no ozonator is that every person-hour uses around 3-1/2 teaspoons of Dichlor or 3-1/2 fluid ounces of 8.25% bleach or 7 teaspoons of non-chlorine shock (43% MPS).  This usage occurs in the hours after the soak usually taking around 8-12 hours though most usage is in the first few hours.  If one has an ozonator, then ozone oxidizes bather waste so the required amounts of oxidizer are roughly half or less what I gave.

Your 1-1/2 tbsp of MPS is 4-1/2 teaspoons so enough to handle around 40 person-minutes of soaking if there is no ozonator.  1-1/2 tbsp of Dichlor which is also 4-1/2 teaspoons would handle around 80 person-minutes of soaking.  It sounds like you aren't adding enough oxidizer after your soak.  If you don't have a silver ion system such as Nature² then the non-chlorine shock you are using will not be a disinfectant for your spa.  The chlorine once a week may not be enough to keep the spa properly disinfected.  You may need to either get a silver ion cartridge or to use at least some chlorine after your soaks (i.e. at least once a day).

In between soaks when there is no bather load the oxidizer gets used up more slowly and the rate depends on the oxidizer.  The Free Chlorine (FC) level usually drops by 20-25% in 24 hours with no ozonator or by 50% or more with an ozonator because ozone reacts with chlorine.  Non-chlorine shock (MPS) gets used up more slowly and may last through the week if there is no bather load (i.e. may lose not more than half after one week).  The loss rate is temperature dependent so if you don't use the spa during the week and let the temperature drop then there will be a slower loss.

[red2play]

From what I glean from the forums (although chem geek seems to know the most) is that you use Dichlor for daily use (before or after each use) and MPS once a week to make it simple (his explanations are spot on but very tech so this is easier to remember).  Most people itch if you use MPS daily and Dichlor weekly.  Like its been said before, around 2 tb without an ozonator and half that with it (or the 3.5 at 104 but who takes it up that far consistently?).  Then a bromine floater (my choice) with Nature 2 mineral stick.  That's what I use and so far its good (maybe I'm overdoing it?) but the levels look good (taylor 2106 kit).