New spa, first fill and getting bright green water after shocking

[cuzpool]

Hi - first post. I've just got a new hot tub. 384US Gallons acrylic - has a filter with a bromine tab dispenser built in. I did the first fill, and followed the instructions. Warmed it up, started adding conditioner, bromine tablets, oxidizer (potassium monopersulphate) and after adding that, it turned quite green the next day. I've read Bromine in My Spa thread a few times. I'm guessing that this is from copper reacting. I'm surprised - this is not well water, it's city water, I would be surprised that it has that much. But - if I can figure out how to upload a pic, I can show how green it is - it's very clear water, but has a very bright green color to it. This fades after a while, but adding more of the oxidizer will make it green again.

After reading the articles here for my pool I bought a Taylor K-2006 kit that I've been using to test. I realized I probably didn't have enough tablets dissolved to get this going properly. With the filter running 24x7 right now, it's already dissolved 3 tablets and I've got 6 more in there and they are maybe half way dissolved. I added more of the oxidizer they gave me and that will get my FC (or Bromine or whatever that tests shows) up, but it quickly will come down below 2 the next day - even with no soak. Adding the R-0870-I barely turns it pink and one drop of R-0871 will make it go clear right away. Seems like I can't get the FC up and I think maybe it's because I don't have bank. The pH is 7.4 and the TA is 90-100 - I can't seem to get it higher.

I'm thinking of draining this and starting over - (or maybe I can save this???) using this guide and getting sodium bromide as suggested. However, I'm worried I drain and I'll be back where I am with green water. I was going to take a water sample (both from the hose and tub) to a pool place to test. I'm just curious as to what you think I can do. They gave me a conditioner, which I added before balancing - it contains Sodium hexametaphosphate, 1-Hydroxyethylidene diphosphonic acid and tetrasodium salt. Maybe I need more of that? Or something different? I'm not sure if this is what I need to get rid of this green color, or when to add it, or if I can save this without doing a drain. Any ideas?

 

[JVTrain]

I would get your fill water and spa water tested for metals. That's the one test I would try first at the pool store. The conditioner looks like it has some sequestering agents for metals (phosphonic acid) but perhaps it's not enough if you have high metals in the water. That would be very odd for city water though.

 

[cuzpool]

I just got back from a local place - they know the water here and it should not have metals. They did a test and found no metals - no copper or iron. They were quite mystified. The chlorine is low - almost none, so I got some sodium bromide and will try to follow the advice here to shock it. See if that clears it. But - they said it wasn't algae and when you look at it in a tube it looks quite clear. Only when you have a few feet can you see this green tinge. If this doesn't clear in the next day or so I'll do a refill...

 

[JVTrain]

What brand, model is your spa? If you could put that in your forum signature, that would help along with the volume. Edit Signature

 

[cuzpool]

Okay - there it is. Hydropool 695 - 384 US Gal.

I added about 250ml of sodium bromide and about 225ml of concentrated bleach. Kept jets on and waited 30 minutes. Tested and it was 5 drops at 10ml - which would be 2.5FC or 5.65 bromine?? If I read that right. I added more to shock it. Waited another 30 minutes. It's now 7FC or 15.75 bromine. Should I go higher? I was going to leave it for a full day or two to see if it changes.

 

[cuzpool]

Well - the FC levels are now off the chart! It's starting to get less green - interesting. I guess it was just not sanitized. I'm still a little confused on the testing of FC in the bromine system. Sanitizer should be between 3 and 5 ppm - so, when I measure using the Taylor drop test 10ml, should I be counting each drop as .5 or 1.125? (.5 X 2.25)? And - when they say - let it come down to below 10ppm before soaking - is that which number, first or second? Basically - I'm just trying to dumb this down to the number of drops I need to aim for. Thanks

 

[JVTrain]

For bromine, each drop is 1.25 ppm with a 10 mL sample. I believe the sticky says maintain 4-6 ppm bromine normally and have it below 10 ppm bromine before entering spa. So... 8 drops in a 10 mL sample would be 10 ppm.

I wouldn't be overly concerned if you were to hop in the spa if the bromine level was 12 ppm. Just don't overdue it before you soak and elevate the bromine level after soaking.

 

[cuzpool]

Great - I read that over again and it was a bit confusing as they said - if it's chlorine, it's one number. Well - I added chlorine, that's what got me confused. But - then I kept reading all the comments. So - the key is, if we have bromine already in there, chlorine converts that so any readings we get are not chlorine - that helped me understand it a lot. Thanks again.

 

[Modawg2k]

I didn't read all of the back and forth, but here is what I do and it works perfectly for my hot tub.

At startup:
- Add sodium bromide (this is your reserve to get your water up to sanitizing levels)
- I add a bottle of sequestrant (I personally just get MetalGon. I also had a bright clear green color once when I didn't use a sequestrant and i went mixing some random chemicals in, I don't know the metal makeup of our water but I haven't had that problem since using a sequestrant at startup).
- I add bromine tabs to a floater

Weekly
- Test the bromine level by testing for cholorine then multiplying by the 2.25. I try to keep my bromine between 2-4 every day
- Add enough chlorine to get my bromine level to above 10 for a shock (this is a FC level of about ~4).
- Test pH and add acid as needed (the bubbles will raise your pH pretty fast, plus I've found that my skin itches when the pH is not close to body pH which is 7.4

 

[cuzpool]

Thanks - yeah - getting used to this slowly. Oddly, after some thought to this, I don't think it was a reaction to metal at all. Which was confirmed when they did a metal test. Although the color looked almost neon. I realized - we had a large bather load and my shock after was not nearly enough. So, by the next day when it was green, I thought it was the shock, but it was just low sanitizer. I think the problem was just not having enough bromine bank. The sodium bromide really helped. I will be set for the next refill.