Cobalt Cure, CC-C12 - 2 lbs

We were battling and battling these black spots that showed up on every scratch and ding on our hot tub. It was so gross.. I had to get the heater fixed and the spa guy recommended this product. In the instructions it tells you to bring your PH level to zero... when we did this.. the black spots disappeared before we even used the product. Used it anyway and we haven't seen anymore (we're keeping our PH levels low now).. so.. I think it works! You have to do your math though.. the bottle is for treating a swimming pool.. not a spa. For our 300 gal spa we used Tablespoons.

BUY THIS!!!We had dark colored stains all through our hot tub. We thought it was algae, even though it made no sense. We keep our hot tub chemistry perfect, so no algae should be growing.We regularly drained the tub to get in there and scrub the stains away with *lots* of elbow grease.The wife found out what we were going through is actually called "cobalting", so I ordered some of this.Dropped the pH to get the alkalinity down to 0, added a little bit of this stuff, the BOOM: stains gone!Ain't Chemistry fun?

this was a reorder- it works

Prompt delivery. I use cobalt cure to maintain my newly resurfaced fiberglass pool. It works great!

Works great. Just needed to be able to read the label for quality of bottles to order for the gallons of the pool.

Good Product