Green tint to water

[Bober78]

I purchased a Caldera hot tub about 6 weeks ago and so far I am loving it.  The only problem I have had is that my water has a green tint.  I have a Taylor K-2006 test kit as it seems go be what people use for Bromine spas.  Here is what my levels are:

Bromine: 4.0
PH: 7.8
ALK: 70
CALC: 160

The water is crystal clear but does have a green tint.  I had a hot tub for about 12 years and never had this problem in the past, but when we moved  4 years ago we finally got around to purchasing a new hot tub again.  I added Baqua Metal Control to the tub at fill up just as i always did in the past with my old spa, and looked fine for about 2 days then the green showed up.  It seems to fade a little during the week but as soon as I shock it it goes green again.

Everything I am reading online points to possibly copper in the water, but yesterday i bought another bottle (this time Leisure Time Metal Gon) but the spa is still green.

Does anyone have any ideas or am I going to have to drain and refill?

[Chief Kyle]

I don't have an answer to why your water has a green tint, but I had a samilar issue.  Every time
I added sanitizer a green tint would appear, but would clear.  I ran some bio-film cleaner, drained, cleaned and refilled the spa...no more issues.  I change my water every 4 months.

[Bober78]

I do seem to be going through alot more bromine to maintain the good levels than i used to on my old tub.  The biofilm may explain that.  I think i will try some of that Ahh Some stuff to see if that cleans out the system.   Would a brand new tub have biofilm?

[Bober78]

I understand that biofilm could be causing  me to use more sanitizer, but why would it cause the green color (i assume copper) even after using the metal gon?

[Bober78]

I ended up draining and cleaning everything really good this weekend.  I refilled and added metal gon and got all the levels where they should be.  That morning I added the initial bromide bank and mps shock and had bromine level at 5.0, but only a few hours later it was down to 2.0.

Is this normal to drop that quickly in a matter of a few hours or does that mean that there is something (possibly biofilm) that is using the sanitizer?

On the bright side the water color is perfect and not green yet