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Baking Soda Nightmare


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#1 mcdlnwright

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Posted 08 February 2008 - 11:43 AM

Ok Guys and Gals I think I'm in trouble here
I have a 7 person hot tub and I have always put Baking soda in to maintain the water clarity.
I put some in the other day and walked away like normal. The next time I used it the entire inner wall and seating area < basically anywhere the water touches> feels like sandpaper. I can scrub it off with a pad but it just comes right back.

I need to get rid of this, I'm afraid it may clog my intake, and I am afraid if I drain it I still wont get it all any ideas?


#2 Dr. Spa

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Posted 08 February 2008 - 11:50 AM

Baking soda is for raising Total Alkalinity.... How are you using it for water clarity?
What the heck do I know, I only started in this industry in 1981, and retired from it after 33 years.
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#3 chem geek

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Posted 08 February 2008 - 12:28 PM

QUOTE(Dr. Spa @ Feb 8 2008, 11:50 AM) <{POST_SNAPBACK}>
Baking soda is for raising Total Alkalinity.... How are you using it for water clarity?

My guess is that you've raised the Total Alkalinity (TA) so high that you've precipitated calcium carbonate (scale) and that's what you are feeling. Get a good test kit, measure your TA level, and if it's sky high as I suspect, drain and refill your spa and don't use Baking Soda except to intentionally increase TA.

#4 Hillbilly Hot Tub

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Posted 08 February 2008 - 12:31 PM

QUOTE(chem geek @ Feb 8 2008, 03:28 PM) <{POST_SNAPBACK}>
QUOTE(Dr. Spa @ Feb 8 2008, 11:50 AM) <{POST_SNAPBACK}>
Baking soda is for raising Total Alkalinity.... How are you using it for water clarity?

My guess is that you've raised the Total Alkalinity (TA) so high that you've precipitated calcium carbonate (scale) and that's what you are feeling. Get a good test kit, measure your TA level, and if it's sky high as I suspect, drain and refill your spa and don't use Baking Soda except to intentionally increase TA.

I will add, when you drain the spa you may need to use a tub and tile cleaner (made for spas, not bath tubs) to clean off the acrylic. The filters may really need to be cleaned out also, maybe replaced if you can't get them clean. It likley also attached/stuck to the heater element, seals, jet internals etc.
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#5 mcdlnwright

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Posted 08 February 2008 - 12:45 PM

QUOTE(Hillbilly Hot Tub @ Feb 8 2008, 02:31 PM) <{POST_SNAPBACK}>
QUOTE(chem geek @ Feb 8 2008, 03:28 PM) <{POST_SNAPBACK}>
QUOTE(Dr. Spa @ Feb 8 2008, 11:50 AM) <{POST_SNAPBACK}>
Baking soda is for raising Total Alkalinity.... How are you using it for water clarity?

My guess is that you've raised the Total Alkalinity (TA) so high that you've precipitated calcium carbonate (scale) and that's what you are feeling. Get a good test kit, measure your TA level, and if it's sky high as I suspect, drain and refill your spa and don't use Baking Soda except to intentionally increase TA.

I will add, when you drain the spa you may need to use a tub and tile cleaner (made for spas, not bath tubs) to clean off the acrylic. The filters may really need to be cleaned out also, maybe replaced if you can't get them clean. It likley also attached/stuck to the heater element, seals, jet internals etc.

I used it Because Arm and Hammer recommended it for clarity. I called their 800 number and they said to put in two cups worth.

Is there anything I can do to help break down the baking soda before I drain it? and something possibly that will run through the system to clean out any deposits in the lines?
like when the coffee pot gets slow and you run vinager through it to clean out the lines< best example I can think of>
I don't mind draining the system but I don't want any hidden deposits to harm the system.
and what would be the best thing to use to get the deposits off the walls

#6 Hillbilly Hot Tub

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Posted 08 February 2008 - 01:12 PM

QUOTE(mcdlnwright @ Feb 8 2008, 03:45 PM) <{POST_SNAPBACK}>
QUOTE(Hillbilly Hot Tub @ Feb 8 2008, 02:31 PM) <{POST_SNAPBACK}>
QUOTE(chem geek @ Feb 8 2008, 03:28 PM) <{POST_SNAPBACK}>
QUOTE(Dr. Spa @ Feb 8 2008, 11:50 AM) <{POST_SNAPBACK}>
Baking soda is for raising Total Alkalinity.... How are you using it for water clarity?

My guess is that you've raised the Total Alkalinity (TA) so high that you've precipitated calcium carbonate (scale) and that's what you are feeling. Get a good test kit, measure your TA level, and if it's sky high as I suspect, drain and refill your spa and don't use Baking Soda except to intentionally increase TA.

I will add, when you drain the spa you may need to use a tub and tile cleaner (made for spas, not bath tubs) to clean off the acrylic. The filters may really need to be cleaned out also, maybe replaced if you can't get them clean. It likley also attached/stuck to the heater element, seals, jet internals etc.

I used it Because Arm and Hammer recommended it for clarity. I called their 800 number and they said to put in two cups worth.

Is there anything I can do to help break down the baking soda before I drain it? and something possibly that will run through the system to clean out any deposits in the lines?
like when the coffee pot gets slow and you run vinager through it to clean out the lines< best example I can think of>
I don't mind draining the system but I don't want any hidden deposits to harm the system.
and what would be the best thing to use to get the deposits off the walls

I have no idea where arm and hammer got that figure, the TA must be off the charts! 80-120 is what is reccommended for TA level and 2 1/2 tablespoons will raise TA 25 ppm per 250 gallons of water. Imagine what your TA is!

First, my suggestion is to use jet clean or swirl away to clean out the lines, heater etc. Spa stores should have these products. You may even have to drain the tub, fill, use swirl away and drain and fill again. There are several products to use to clean the acrylic, most spa stores should have them. I personally like Sea Klear thick tub and tile cleaner to clean the walls. You just need to get one made for hot tubs not bathrooms because you do not want the soaps and stuff that are in the bathroom cleaners.

After that you, if you let the forum know what chemical system you are using there are several people that will help you with the proper chemical maintenence to keep the water clear. Good luck.
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#7 mcdlnwright

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Posted 08 February 2008 - 01:20 PM

i don't have any local places in my area, In the boonies. What about clr would that work? I could dump the entire bottle in and let it run isn't it used for calcium as well?

Someone at lowes suggested muriatic acid but from what i read that would be the the right thing that is usually used for ph right?

if neither of those would work could you possibly recommend somewhere online?

#8 Hillbilly Hot Tub

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Posted 08 February 2008 - 01:42 PM

QUOTE(mcdlnwright @ Feb 8 2008, 04:20 PM) <{POST_SNAPBACK}>
i don't have any local places in my area, In the boonies. What about clr would that work? I could dump the entire bottle in and let it run isn't it used for calcium as well?

Someone at lowes suggested muriatic acid but from what i read that would be the the right thing that is usually used for ph right?

if neither of those would work could you possibly recommend somewhere online?

There is a link at the top of this forum, discount spa chemicals, they have both products I am speaking of. The jet clean is a leisure time product and the Sea Klear tub and tile is also listed on their site. I would not use CLR. You need to change the water, not worry about adjusting the PH right now. I would say it is to far gone. Get your tub cleaned up and start fresh.
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#9 spatech (the unreal one)

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Posted 08 February 2008 - 02:05 PM

QUOTE(Hillbilly Hot Tub @ Feb 8 2008, 01:42 PM) <{POST_SNAPBACK}>
There is a link at the top of this forum, discount spa chemicals, they have both products I am speaking of. The jet clean is a leisure time product and the Sea Klear tub and tile is also listed on their site. I would not use CLR. You need to change the water, not worry about adjusting the PH right now. I would say it is to far gone. Get your tub cleaned up and start fresh.


I can't say that I'd do that. I think you need to get your ph back in order BEFORE you dump it. You have all that scale because you screwed up your ph and it precipitated out of the water. By getting your ph back in order you can get a lot of that scale back into solution before you dump (and I'd actually bring it to the lower end of the acceptable ph scale to get as much scale back in solution as possible).

#10 chem geek

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Posted 08 February 2008 - 02:28 PM

Let's say that 2 cups of baking soda was added to 500 gallons (my guess for the size of a 7 person spa) and that the initial TA was 80. This would raise the TA to around 260 ppm. As for what happens with calcium carbonate saturation, that depends on the Calcium Hardness (CH). If it was only 50 ppm, then this would only be somewhat over-saturated. At 100 ppm, it would be seriously over-saturated.

So I agree that lowering the pH to around 7.0 will help to dissolve some of the calcium carbonate scale. To go from a pH of 7.8 to 7.0 at a TA of 260 ppm would take 5 ounces weight (3.3 fluid ounces volume) of dry acid in 500 gallons, but since we're just guessing at water volumes and TA levels any acid that is added should be added in smaller amounts and the pH remeasured after 5 minutes of mixing.

On the other hand, doing a drain/refill with water that is lower in TA will also help to dissolve the scale and the pH can be lowered at that time as well. To get rid of the excess carbonates that come from the dissolved scale, one needs to aerate and add acid to keep the pH low. Since this "low pH, aerate, add acid" is probably going to have to be done anyway, I don't know if it's better to lower the pH now when the TA is so high rather than just do this later when the TA will be lower after a fresh refill.

It's a good idea, I just don't know if it matters that much whether he dissolves some scale now before a refill or does all of it after a refill. It's going to be a chunk of work either way.

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#11 spatech (the unreal one)

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Posted 08 February 2008 - 03:17 PM

QUOTE(chem geek @ Feb 8 2008, 02:28 PM) <{POST_SNAPBACK}>
It's a good idea, I just don't know if it matters that much whether he dissolves some scale now before a refill or does all of it after a refill. It's going to be a chunk of work either way.

Richard


I guess I've always been of the school of thought to dissolve as much of the scale as you can back into the water and then dump it. You can get an awful lot of that scale back into solution and it seems counterproductive to try to do it with the new water. I will admit that I am not a chem guy in life, just someone with experience in spa water management and that's how I've always seen it taken care of and passed on to others. I usually bow to those who can answer the "why" part of chem questions because I can usually only answer the "what" portions but I would get that scale back into that old water and then dump!

#12 Chas

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Posted 08 February 2008 - 03:40 PM

This is urgent: DO NOT drain the tub.

Simply add 'spa down' or dry acid. Start with a couple of dry ounces - four at the most at one time. If you don't have any of that on hand, use vinegar.

The point here is that you precipitated calcium out of the water, and now you need to nudge it back where it came from. Lower your pH to around 6.8 or so, and plan on working to keep it there for the next few days. The scale will go away like magic.

If you drain and scrub, you can scratch the surface badly, you will not be able to get it all out of the jets, plumbing, heaters pumps and filters.

So - add acid. Test four to six hours later. Repeat as needed for about three days, or until it's all gone.

THEN drain and refill the tub if you wish.

This happens to the best of us, but if you delay you can cost yourself a heating element. In fact, it's not really a bad idea to turn off the heat for the first day or two. I can't tell you how many times I have walked customers through this - we have wide swings in our tap water pH in town, and it catches some of my most experienced customers off guard.
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#13 chem geek

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Posted 08 February 2008 - 03:42 PM

Practice trumps theory every time, especially in terms of what's practical. I didn't disagree with your approach, so it's certainly something to be done though FIRST a good test kit is needed or else there's no way to know the current water parameters nor how much acid to add to get closer to 7.0 pH before dumping the water. So, mcdlnwright, are you clear what to do? Test your water parameters and add the appropriate amount of acid to get the pH lower -- closer to 7.0 -- and then wait a bit to see the calcium carbonate seems to dissolve. The pH will tend to rise, so add more acid to keep it low. After it seems to stop dissolving (i.e. no further progress is made), dump and refill. Then check back in with us and we'll go to the next step if needed.

[EDIT] I see Chas has chimed in so just follow what he has said which is consistent with what spatech proposed. [END-EDIT]

#14 Mr Solo

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Posted 08 February 2008 - 07:58 PM

When I bought my spa I was told to use as little chemical as I could. I remember him telling me "less is more", and I have never put two cups of anything into my spa. After you get your spa back to normal, buy a Taylor test kit and only add chemicals when needed, and then as little as you can for the desired adjustment.

#15 Chas

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Posted 08 February 2008 - 11:16 PM

Baking soda is the secret ingredient in 'Spa up.' In the future, feel free to use it, just add two ounces at a time. Two cups would do this to just about any tub.

To give you some parameters - I used to run a 500 gallon tub on well water with a pH of over 8.0. I had to add about 6 ounces of Spa Down, which is dry acid, to get it down to around 7.4. I had to add four ounces - which is about the most you want to add at a time - and then test in four hours. I would then add another two, or sometimes three ounces and all would be good.

If I didn't do this AS I WAS FILLING, I would have a light haze on the surface within a few hours, and the scale would be thick the very next morning. Don't ask me how I know...

If you are using test strips, the practical guide is like this: in 500 gallons, one color block on the test strip bottle takes about two ounces.

If you retest too soon, you will panic because the pH tends to drop real low and then level out. Four or five hours.

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#16 Hillbilly Hot Tub

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Posted 09 February 2008 - 06:44 AM

QUOTE(Chas @ Feb 9 2008, 02:16 AM) <{POST_SNAPBACK}>
Baking soda is the secret ingredient in 'Spa up.' In the future, feel free to use it, just add two ounces at a time. Two cups would do this to just about any tub.

To give you some parameters - I used to run a 500 gallon tub on well water with a pH of over 8.0. I had to add about 6 ounces of Spa Down, which is dry acid, to get it down to around 7.4. I had to add four ounces - which is about the most you want to add at a time - and then test in four hours. I would then add another two, or sometimes three ounces and all would be good.

If I didn't do this AS I WAS FILLING, I would have a light haze on the surface within a few hours, and the scale would be thick the very next morning. Don't ask me how I know...

If you are using test strips, the practical guide is like this: in 500 gallons, one color block on the test strip bottle takes about two ounces.

If you retest too soon, you will panic because the pH tends to drop real low and then level out. Four or five hours.

cool.gif

I would like to add that the tub and tile cleaner by Sea Klear does not scratch the tub, If you apply it with a sponge it takes the scale right off, no scrubbing, it also works well on some stains. I use it all the time and have never scratched a tub. The swirl away products also helps to remove the scale off the tub. He could have this all done in a day rather than days waiting for the PH to adjust back down and water to clear up, why fight with it? I like to use my tub, not wait for water to adjust back to correct levels and hope I got all the scale taken care of. I guess I like to keep it simple. Anyway, good luck with it!

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#17 spatech (the unreal one)

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Posted 09 February 2008 - 09:06 AM

QUOTE(Hillbilly Hot Tub @ Feb 9 2008, 06:44 AM) <{POST_SNAPBACK}>
I would like to add that the tub and tile cleaner by Sea Klear does not scratch the tub, If you apply it with a sponge it takes the scale right off, no scrubbing, it also works well on some stains. I use it all the time and have never scratched a tub. The swirl away products also helps to remove the scale off the tub. He could have this all done in a day rather than days waiting for the PH to adjust back down and water to clear up, why fight with it? I like to use my tub, not wait for water to adjust back to correct levels and hope I got all the scale taken care of. I guess I like to keep it simple. Anyway, good luck with it!


Those products may work fine but the point is (s)he's definitely much better off balancing the ph and getting the scale back in th water to greatly reduce what has to be manually and mechanically removed.

#18 Chas

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Posted 09 February 2008 - 05:51 PM

QUOTE(spatech (the unreal one) @ Feb 9 2008, 09:06 AM) <{POST_SNAPBACK}>
fine but the point is (s)he's definitely much better off balancing the ph and getting the scale back in th water to greatly reduce what has to be manually and mechanically removed.


Not to mention the harsh chemicals. It's my planet too....

To me, the 'easy way' is to just drop the pH and keep it down. No reason you can't use the tub, though it may bother extra-sensitive skin.

But - to each his own.

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#19 chem geek

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Posted 09 February 2008 - 10:39 PM

QUOTE(Chas @ Feb 9 2008, 05:51 PM) <{POST_SNAPBACK}>
Not to mention the harsh chemicals. It's my planet too....

To me, the 'easy way' is to just drop the pH and keep it down. No reason you can't use the tub, though it may bother extra-sensitive skin.

But - to each his own.

cool.gif

Since we don't know the Calcium Hardness (CH) then we don't know the saturation level even at lower pH of 7.0 so we don't know if 1) all the scale will get redissolved and 2) if at the higher temps in the gas heater that scale won't still form. So I totally understand why lowering the pH to redissolve at least some (and perhaps most or all) of the scale would be reasonable to do, but the high TA would still need to be dealt with, especially if the CH is on the higher side (even above 100). If one doesn't do a drain/refill then this means continued addition of acid over time to keep the pH low (which I believe is what you mentioned) -- and to make the process go faster additional aeration can be done (which makes the pH rise so acid would need to be added more frequently). The drain/refill is just a faster way of lowering the TA (assuming the fill water isn't high in TA), but I understand why getting at least some of the scale redissolved right away in the "bad" water is a good approach. I just wish I thought of it first :-) but that's why we've got multiple experienced people helping others out on this forum (unlike myself who mostly just deals with the theoretical side).


#20 waterbear

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Posted 11 February 2008 - 12:42 AM

I also have to agree with dropping the pH first before draining. Much of the scale should hopefully redissolve and THEN you can dump the water. If it doesn't then you have only lost a few days and some acid and can then try the drain and clean, which is going to be much more work.
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