Hotspring Freshwater Salt System - working?

[snaxmuppet]

I got my first hot tub 4 weeks ago. It is a Hotspring Flair with the Freshwater Salt system. It was set up by my local Hotspring supplier and they gave me a rather quick intro to water management before they left and with that, and with reading loads on the internet (including here!) I thought I had a handle on it. But I do have a few questions which I am hoping you might be able to help with...

The Freshwater Salt system is struggling to keep up with my use. It seems that no matter what setting I use (even boost) there is no chlorine at all shown on the strip in the morning. I then dose with the chlorine granules to bring it up to 3ppm but it never gets higher than that even on boost and then the following morning it is back down to near zero. Is the Freshwater Salt system faulty? The water was shocked when first filled to over 10 so I know it started clean and I have shocked to 10ppm 3 more times as well each weekend just to be sure! TA is 60-80 and pH is 7.4 so that is all good.

When is the best time to add sanitiser? I have seen a mix of advice... morning, before use, after use etc... 

When is the best time to take a reading? 

I would like to get to the point where I can just set the Freshwater Salt system to a sensible setting to cope with my normal weekly use and then only add chlorine if it is used more than that or with more people... is that even possible if it is used daily for 2 people for 30 mins? At the moment, it is not showing any sign that it is producing chlorine at all tbh (0.5 on the test strip) although the water is still clear.

Have to admit to being rather confused.

[earesearch]

You are not alone on this.  I have a 2019 vangard tub with a freshwater salt generator system.   We use the tub 1-2 times per week; and the residual has difficulty showing up on the test strip.  I have it set to setting of 6 and use the 24 hour boost mode after use as well as adding extra granulated chlorine.  

My tub actually came with a ozonator as well; which has been disconnected after I installed the salt chlorinator ($250 from dealer).  I am thinking of running both ozone and the salt generation system to make it nearly maintenance free.

Before I had the salt chlorinator the ozone was active (I added it after purchase of hot tub) and the water always smelled good; in many ways I was happer with ozone + mps and occasional chlorine once per week.  The issue is the chlorine residual will rarely show up on a test strip, but since I now have both a salt chlorinator and ozone I am going to give it a shot to run both and use granulated chlorine/mps only when the tub has been used.  Frustrated but I think this will work well.  The free chlorine will oxidize the ozone and produce a residual of o2 and chlorine ions; however it will double the free chlorine oxiation; requiring more chlorine production.  Guess i'll up the setting to 8 on the salt generator and see how it goes for a few months.  In theory I should not have to do anything but add mps/chlorine after use with both of these.

B

 

[snaxmuppet]

I am still having some doubts as to whether the salt system is working so I decided to drain down and start over with fresh water and give it another go. My water was 6 months old and so I thought it could be CYA lock and as I have only been using dichlor for sanitisation and shocking it could have a lot of CYA. The CYA on the test strips is useless as there is so little difference in colour between the different levels.

This is the first refill since new and my first observation after draining, cleaning and refilling was how clean the new water looks and feels. Perhaps it was just old water.

I raised TA to 80 with sodium bicarbonate, CH was already at 50 so no adjustment (its low because of the salt system), I shocked with 3 small scoops of dichlor taking it to over 10ppm (max reading on the strip) and I heated to 38°C. I then set pH to 7.6 with some pH down (sodium bisulphate). This process was really easy and the water is now sensibly balanced as far as I can tell.

I added the recommended amount of salt (for the Flair it is 2kg) and set the salt system to 7. The salt system looked fine (in the green).

We started to use the tub. 2 of us, almost every day for 30 mins. After each soak I dipped and raised FC back to over 5 with dichlor.

This has gone on for about 5 days so I guess that there is sufficient CYA ( not measuring because of the strips mentioned above) so I have now switched to liquid chlorine. 

I haven't touched the salt system. It is still on 7. I am finding that I am having to add less and less chlorine after use to get back to 5 so perhaps the system is working after all... of a fashion! It is still under a week since the refill so I will give it a week or two longer before coming to my final conclusion. 

I haven't needed to shock yet after the refill (apart from the initial shock that is) but as I am now using liquid chlorine I will try to use MPS as that will help keep the pH down.

If anyone has any comments/advice on all this please shout...