Algie??

[Bosmani]

friend has an indoor pool with hot tub attached. The pool has a sand filter and the tub standard finned paper filter. He uses bromine tablets in both as well. He has black staining comming from the floor jets in the tub aand I feel it may be an algie? Had to rub off but will with a scrub. Any thoughts on cause or cures please?

[hottubdan]

Does he use an algaecide?

[Bosmani]

Dont think so, The usual PH up and down, TA , and sanatiser.

[drewstar]

Yuk.

I don't know the ramifications of having the hot tub and pool exchning water, but

With my outdoor AGP, for algie, I use an algicide (the black aglicide, can't remember the name, but a dealer will know it). Scrub the sides, and for good measure, he could replace the sand in the filter.  ($30)

Clean the Hot tub filter and super chlorinate.

If this doens't do it,  I think he's looking at a complete water change out.

[Bosmani]

Thank you

[Micah]

We used to have problems with "Kobalt" on older gel-coat spaswhere black stuff would seep out of pours in the shell.  Only applies to older spas.  If so drain and clean with acid / water mixture (kind of like acid washing a pool) and a great addition to you chemicals to stop it from coming back is a product called "Kobalt Killer" from ARM products

[Chas]

 Yes! Kobalt Killer is the bomb on the 'black plague.'  

I have been in the biz long enough to have done battle with this nemesis many times, but as mentioned, not on the newer tubs.

And never on a HotSpring, since they don't have fiberglas backing.