I keep getting this smell in my water?

[squale]

I have a Sundance Altamar hottub in my garage.  I just changed the water last week.  I only use Dichlor and then once a week MPS.  Well a couple days ago I go to get in the hottub and I notice a weird smell in the water.  I don't really know how to explain the smell.. sort of chemical like but not purely chemical.  I notice that on the inside top of my cover I have a bunch of black dots.. I think this might be black mildew?

I'm not sure how I am getting this.. I put about 2 teaspoons of Dichlor in the tub after everytime I use it or every other day.  Sometimes I don't get to use the tub everyday so it may sit closed for a couple days at a time.

I have an ozonator in the tub as well.  and my water is balanced.  After a new refill my PH and Alk are very high but I use PH decreaser to bring them down.  But I still am getting this weird smell in the water and these black dots on the inside top of the cover.

What do you think could be the problem?

this last water change I also installed a new filter so I know the tub should be functioning perfectly.

any help would be appreciated?

[Chad]

The mildew on the underside of your cover is not out of the ordinary. You need to wipe it down every week or so after one of your post soak dichlor doses and you won't have that problem anymore. As far as the smell...I don't know. It could just be the smell of the O3 from your ozonator or maybe there's a lot of CC present. Do you test for CC? I know if I don't open the cover for a few days, I'll get a strong ozone smell.

[squale]

what is cc?

I never knew that the mildew on the cover was normal?  is there mildew INSIDE the cover maybe too?

[hottubdan]

what is cc?

I never knew that the mildew on the cover was normal?  is there mildew INSIDE the cover maybe too?

That could be your problem.  You can remove the cores to check.  I think you got the tub used, didn't you?  How old is the cover?  Often persistent odor is mildew in the cover.

cc is combined chlorine, or used up chlorine.  We shock to get rid of cc.

[ndabunka]

what is cc?

I never knew that the mildew on the cover was normal?  is there mildew INSIDE the cover maybe too?

I've NEVER had mildew under (or over) my cover in the five years I've owned it so I'd say that it may depend on where you live.  This is in Charlotte, NC.  Also, I would think that the effect of the ozonator might at least be partially why I never have had mildew.  Maybe your ozonator's life has been expired?  How long has it been since you changed it and which one do you have?  If it's the UV one and it's more than 2.5 years old, it have probably already stopped functioning.

[squale]

I have a 2004 sundance altamar with the cd ozonator from sundance.

if you have mildew in the cores of your cover what can you do to fix this?

I doubt this is the reason for the smell in the water because the first 5 months I had the tub I never had this smell.  It's just been lately in the last 2 water changes that I have had this smell and the black spots on the underside of the cover..

could it be because I often don't open the spa for a couple days at a time.. so thereofre it's not breathing enough?

[Gomboman]

How often do you shock to eliminate your combined chlorine levels? I'm thinking you have excess combined chlorine levels as the previous posters suggested.

[squale]

I shock once per week with MPS.  Besides how could my CC levels be that high only 2 weeks after a new water refill that my water is already smelling and I am having block spots on the inside of my cover.