new spa startup

[planker88]

new 400 gallon hot tub (Marquis 660) - added well water. have a softener. ran for the last 2 days and added some bleach initially (about 15-20 ounces, or 1/8 bottle of 8% bleach) since i thought BBB was the way to go. here are the 1st test results:

8.4 ppm FC
1.0 ppm CC
90 ppm TA
pH 8+
CH too low to measure - stays blue

Using Taylor k-2006 test kit.

The softener for our well takes out high levels of iron and manganese. As a result, the water is very soft.

Currently the hot tub water is nice and clear, but smells strongly of chlorine.

I figured I need to shock it so I added 4 tsp of dichlor per the "superchlorination" instructions on the bottle.

I wanted to lower pH so I added "pH down" per the instructions on the bottle, 3 tsp dry acid.

The manual says "Dont use soft water" so after those chemicals settle in I plan to add some calcium chloride (pool calculator says to add 20 oz to get to 260 from "zero" -- not sure if I am at zero. The user manual recommends a range of 200-300 ppm.

Am I on the right track?

Thanks in advance for any help you might offer.

PS the spa store set me up with a nature 2 cartridge to put in the filter, but i read a lot of negative comments on that mineral sanitizer so I have not put it in yet.

If anyone recommends it or uses it please advise, thank you!!

 

[chem geek]

I don't know why your manual says not to use soft water and to have the Calcium Hardness (CH) at 200-300 ppm since that can risk scaling in the gas heat exchanger in the spa. Your spa isn't plaster or have tile with grout, does it? If it's a standard acrylic spa, there is no need for calcium in it. However, having 120-150 ppm CH is helpful to reduce foaming so you can add enough calcium chloride to get to that CH level.

You'll want to use Dichlor initially to build up the CYA level before switching to using bleach. Did you read Using Chlorine in a Spa? That will give you more info, but if you plan to use the Dichlor-then-bleach method then your TA should be lowered to around 50 ppm and you need to add 50 ppm Borates (say, from boric acid) and that is not optional.

Nature2 can be used with non-chlorine shock (MPS) where chlorine is only used once a week or so as needed. In that system, the silver ions from the Nature2 plus the MPS you add and maintain are the disinfectant. It's a more expensive approach, but it is low chlorine and EPA approved. Up to you. If you have an ozonator and aren't soaking every day or two, then a chlorine approach can be more maintenance since you'd have to dose every day. That's because ozone reacts with chlorine so increases chlorine demand in between soaks, though it reduces chlorine demand from bather load. So ozonators work well for chlorine spas used every day or two, but not for spas used less frequently.