Black Mold

[Kansas74]

I just switch to a SWG my hot tub. NOw I am noticing black mold. It's been about 3 months since i have changed the water and switch to SWG. In the past I normally change the water 5 to 6 months. going to test the water will post shortly.

Dan

 

[Kansas74]

PH is 7.6 but the CH is non existing. the salt lever was around 2500. Going to change the water and not sure if going back with the SWG. Normally I always kept the CH around 2 or 3 but having a hard time keeping CH. I have the Salttron Mini running 23 hours a day. Thinking this was not a good idea

 

[chem geek]

I think by CH, which we usually use for Calcium Hardness, you mean chlorine level such as Free Chlorine (FC). Do you have any Cyanuric Acid (CYA) in the water? If not, then the chlorine produced by the SWG is too strong and it will outgas too quickly as well. Is the black mold forming because the chlorine level is getting to zero because the SWG is not able to output enough? You might try adding around 30-40 ppm CYA and see if the SWG is then able to output enough chlorine. Also note that the SWG will probably be able to add enough in between soaks, but may not be enough to handle a higher bather load, especially if you soak every day or two, though that depends on the SWG you are using. Some have a boost mode where if run for a longer time they are able to keep up.