Initial treatment after filling from lake

[JoshNZ]

Hi everyone,

New to the forum here, have recently purchased a second-hand 7x7' coast spas hot tub and hoped to pick some brains

As the title says... It is installed at the cottage which has the lake as its only water source. After filling, it is a very light shade of green and slightly cloudy. I wondered what the initial steps are to get it back to clear (or whether it's even possible?) and if maintaining the water after that should be any different. I'd planned on using bromine to sanitize (after reading about the 3-step method here) so will pick up the necessary chemicals for that tomorrow. But what would you do differently, for initially treating lake water?

Also... After initially filling and running the jets blew out a bunch of white flecks, almost resembling fish scales but soft (not really slimy). I emptied and refilled but there is still a little in there. Anybody have any idea what this stuff is and how to be rid of it properly?

Many thanks in advance!
Hope to stay part of the community here looks like a great resource!
Josh

 

[JVTrain]

No well on the property either?

I would say that to get things cleared up faster, operate the tub with the two step method first. Get the sodium bromide in the water, adjust pH as needed with acid or borax then add bleach to super-oxidize. Probably two cups of bleach to start and then I would test often and keep that bromine up near 10 ppm for as long as it takes to clear up. Once the water clears up, then you could go to bromine tabs in a floater.

What sort of a test kit are you going to use? I would get a Taylor K-1000 or similar at a minimum. Avoid test strips.

 

[JoshNZ]

No well on the property either?

I would say that to get things cleared up faster, operate the tub with the two step method first. Get the sodium bromide in the water, adjust pH as needed with acid or borax then add bleach to super-oxidize. Probably two cups of bleach to start and then I would test often and keep that bromine up near 10 ppm for as long as it takes to clear up. Once the water clears up, then you could go to bromine tabs in a floater.

What sort of a test kit are you going to use? I would get a Taylor K-1000 or similar at a minimum. Avoid test strips.

No well here I'm afraid.

I haven't got a test kit yet, I have the strips but I will see what is available at the local pool store.

So bromine tablets are not sodium bromide right? (i.e. I can't just crush them?) I need granulated sodium bromide and enough to keep it up at 10ppm? How long would you expect it to take to clear up?

Are calcium and Alkaline as important to watch?

And... finally, (for now lol) You don't go in it with the bromine up at 10ppm right?

 

[JVTrain]

Any test at the pool store that measures chlorine and bromine through what's normally called an OTO test will work. Most OTO color match tests come in a plastic block and the other side of the block is a pH test. Many stores carry them and they are often referred to as a 3-Way test kit.
Example at WalMart stores:

Bromine tablets are (courtesy of chem geek): BCDMH stands for bromochlorodimethylhydantoin or 1-bromo-3-chloro-5,5-dimethylhydantoin while DBDMH stands for dibromodimethylhydantoin or 1,3-dibromo-5,5-dimethylhydantoin. Long names I know but basically the first one will add both bromine and chlorine to the spa while the second only adds bromine. If you use these tablets for a few weeks, you'll build up a bromide bank. In your case of starting with contaminated (in an organics content sense) water, I would for sure go straight for building a bromide bank with sodium bromide instead of waiting for tablets to build a bank. You want 30 ppm or slightly more sodium bromide for the bank.

Once you have the bromide in the tub, then adjust the pH. The cheapest way is using muriatic acid. However, you'll never need a whole gallon of the stuff. It'd probably last you a year or more. I would pick up the more expensive, but convenient powdered pH down product that you can get at the pool store. This product will also add sulfates to the spa, but that's not much of a problem on a fiberglass spa and the convenience and smaller quantity of powder makes more sense. You'll need this to keep the pH down, depending on the alkalinity of the water. Then get to adding bleach to maintain the 10 ppm total bromide. Switch to tablets if you like after the water clears or just shock/oxidize with bleach to renew the bromine from the bromide bank.

Calcium is fairly irrelevant unless it's very low. You'll know it's low or non-existent if you get excessive foaming after the water has cleared. Alkalinity or total alkalinity is important but you only need to worry about maintaining pH and alkalinity will take care of itself... for the most part. Ideal alkalinity for a spa is about 50 ppm. If you maintain pH by only lowering it when it rises above 7.8 pH, eventually the pH rise will slow some and you'll know your alkalinity is pretty good. Unless the lake water happens to be very low in alkalinity, you will see pH rise with all the aeration normally present in the spa.

While clearing the water with bleach additions, check the filter regularly and circulate (run the jets) as much as you can to help filter particulates. Clean the filter often. It will probably take several days of dosing and watching the TB (total bromine) and pH levels. Reread the bromine spa sticky, including the responses which also discuss some common questions.

You can be in the spa at any time when the total bromine is less than 10.

 

[JoshNZ]

Any test at the pool store that measures chlorine and bromine through what's normally called an OTO test will work. Most OTO color match tests come in a plastic block and the other side of the block is a pH test. Many stores carry them and they are often referred to as a 3-Way test kit.
Example at WalMart stores:

Bromine tablets are (courtesy of chem geek): BCDMH stands for bromochlorodimethylhydantoin or 1-bromo-3-chloro-5,5-dimethylhydantoin while DBDMH stands for dibromodimethylhydantoin or 1,3-dibromo-5,5-dimethylhydantoin. Long names I know but basically the first one will add both bromine and chlorine to the spa while the second only adds bromine. If you use these tablets for a few weeks, you'll build up a bromide bank. In your case of starting with contaminated (in an organics content sense) water, I would for sure go straight for building a bromide bank with sodium bromide instead of waiting for tablets to build a bank. You want 30 ppm or slightly more sodium bromide for the bank.

Once you have the bromide in the tub, then adjust the pH. The cheapest way is using muriatic acid. However, you'll never need a whole gallon of the stuff. It'd probably last you a year or more. I would pick up the more expensive, but convenient powdered pH down product that you can get at the pool store. This product will also add sulfates to the spa, but that's not much of a problem on a fiberglass spa and the convenience and smaller quantity of powder makes more sense. You'll need this to keep the pH down, depending on the alkalinity of the water. Then get to adding bleach to maintain the 10 ppm total bromide. Switch to tablets if you like after the water clears or just shock/oxidize with bleach to renew the bromine from the bromide bank.

Calcium is fairly irrelevant unless it's very low. You'll know it's low or non-existent if you get excessive foaming after the water has cleared. Alkalinity or total alkalinity is important but you only need to worry about maintaining pH and alkalinity will take care of itself... for the most part. Ideal alkalinity for a spa is about 50 ppm. If you maintain pH by only lowering it when it rises above 7.8 pH, eventually the pH rise will slow some and you'll know your alkalinity is pretty good. Unless the lake water happens to be very low in alkalinity, you will see pH rise with all the aeration normally present in the spa.

While clearing the water with bleach additions, check the filter regularly and circulate (run the jets) as much as you can to help filter particulates. Clean the filter often. It will probably take several days of dosing and watching the TB (total bromine) and pH levels. Reread the bromine spa sticky, including the responses which also discuss some common questions.

You can be in the spa at any time when the total bromine is less than 10.

Ok. I understand all of that thanks a bunch for your effort.

And, total bromine must be less than 10ppm for safe bathing, what about bromide ions, is there a level they should be under for safe bathing? This is not measurable anyway is that correct?

Thanks again,
Josh

 

[JVTrain]

Bromide ions don't matter so much as they are rather inert when it comes to activity, harmfulness, etc. Just add the 30 ppm and they'll be there for likely as long as you use the tub before draining and refilling as recommended every 3 months. It is not measureable directly.

 

[JoshNZ]

Bromide ions don't matter so much as they are rather inert when it comes to activity, harmfulness, etc. Just add the 30 ppm and they'll be there for likely as long as you use the tub before draining and refilling as recommended every 3 months. It is not measureable directly.

So I got the water pretty clear actually, much to my surprise. Plenty of pumping and constant filter cleaning like you suggested. I still haven't picked up sodium bromide as it is going to get drained and relocated after this weekend again, I just used crushed tablets for now.

After all the reading I've done I can't find exactly how much of everything to use? If I pick up sodium bromide how much do I add to a ~1000L tub? Hopefully it is specified on the directions? And then for shocking/activating bromide, would tabs work by themselves with their chlorine content, or would you use chlorine or MPS after each use? If the latter, how much do you use for that? I have been using a splash of purox at night as it's getting heavy use right now, with all the excitement of a new tub. But I would like to know how to work out exactly how much chlorine should be used to achieve 3-5ppm bromine.

 

[BobbyR]

Is there some reason why you decided to use bromine instead of chlorine? I ask because I've used both and chlorine is less expensive, easier and works better.

 

[JoshNZ]

Is there some reason why you decided to use bromine instead of chlorine? I ask because I've used both and chlorine is less expensive, easier and works better.

Actually it's not my spa I'm staying with my partner and her parents at the moment and they just got it and had decided they wanted to use Bromine. I'm happy enough with it anyway, hasn't been a single day where it smelled chemically yet. Our chlorinated spa at home has the odd bad day.