meggiesmum

Thanks Richard most appreciated.

Hi I'm a new 500 gallon hot tub user so apologies for any naive questions. I've been using chlorine troclosene sodique dihydrate (french name as live in france), in granule form. Since last Tuesday have added 2 tsp per day and have not as yet had any chlorine readings on my test strips. Have checked test strips by dipping in glass of tap water with sml amount of chlorine added to see if any results show - all ok. To start the Ph was a little high so regulated that first before adding any chlorine. Total Alkalinity Ok. The water is not cloudy, quite a lot of foam, but according to hot tub supplier this is normal with new hot tubs. Have noticed today a brown/black substance around the water level on the hot tub - tannin??? How long after adding chlorine do I test water? Any thoughts and comments appreciated. Regards and thanks