Dichlor/Bleach Method

JLS

0
Jun 3, 2015
5
Winnipeg/MB
I've seen reference on other threads to a technique for Spa maintenance that seems to alternate Dichlor and Bleach as a fairly fuss free maintenance program. I believe it was chemgeek who mentioned it, but the exact details were not given. I just refilled my tub and am due to purchase chemicals. I HATE bromine tablets/feeder and shocks and clarity and the plethora that my spa place would have me believe I need to be adding every week. Please advise on what this Dichlor/Bleach method is!!
 
Welcome to TFP! :wave:

The method is described in the sticky How do I use Chlorine in my Spa. Note, however, that unless you are using the spa regularly every day or two, then the method may be more work than you are willing to do compared to bromine tabs in a floating feeder. The reason is that you need to maintain a chlorine level in between soaks.

Also, the method requires some work after a fresh fill to get the water in balance, but after that it should last at least twice as long between water changes compared to Dichlor-only or bromine. It will certainly be the least expensive method because bleach is not expensive.

The method starts out using Dichlor until the Cyanuric Acid (CYA) builds up to around 30-40 ppm (after cumulatively adding around 33-44 ppm FC over time). You then switch to using bleach (except once a month one day of Dichlor use). In order to prevent the pH from rising from carbon dioxide outgassing, the Total Alkalinity (TA) is lowered to around 50 ppm and 50 ppm borates are added (usually from boric acid) for additional pH buffering. After that it's just adding bleach after each soak in proportion to the bather load and adding more chlorine in between soaks if one isn't soaking regularly.

So it's not a trivial method, especially at first, but it results in the best water quality.

Before you do your next refill to start the method, I strongly suggest you use Ahh-Some in the spa as it will get rid of any biofilms or greases that may be present so that you start with a clean slate. Even new spas can have such problems.
 
Been using bleach in my tub for about 18 months. Love it! I don't do dichlor because I don't have any. I do have cya/stabilizer that I use in my pool so I just add it in a sock when I refill and go straight to bleach. Make sure to add the borates, it makes all the difference. I also have a little epsom salt in mine, seems to help. All I ever put in my tub once cya and borates are set is muriatic acid to lower ph and bleach every time we soak and every couple of days if we don't. But since we use it almost every day we just put 1/8-1/4 cup in after we get out. Retest every few days to make sure there is enough chlorine in there.
 
Yeah, technically putting in pure CYA first is a faster way to get to the optimum active chlorine level. We only use Dichlor for this approach because 1) most spa users have Dichlor already so it's a way for them to eventually use it up, 2) spa-only users (i.e. without pools) typically don't have any pure CYA, and 3) Dichlor dissolves immediately so doesn't require a sock method like pure CYA so is perhaps a tad easier especially since with soaks one adds a reasonable amount of Dichlor for chlorine anyway so gets the CYA in as well. Not a big deal either way since both work well.
 
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