All Clear Soda Ash vs Rendesvous pH Up

[Snowbird]

When the tub was delivered, the dealer sold me 1 lb bottles of Rendesvous pH Up and pH Down.  I use far more Up than Down (mineral stick, ozonator, & Activate).  They sell for $6.95 each (plus 7% tax) at the dealer.

I bought a 5 lb container of All Clear Soda Ash  for $7.49 (0% tax & free shipping) from Doc. (It's like getting 4 lbs free.)

The All Clear says it contains 100% Sodium Carbonate.

The pH Up says the active ingredient is Sodium Carbonate but gives no hints as to the other ingredients. (probably some kind of inert filler) :-/

I'm thinking there is no real difference between these two pH raisers but I want to tap into the vast field of hot tub lore and knowledge on this forum to be sure before I use it.

I'm trying to figure out why anyone would pay $7.05 a pound for something they can get for $1.59.



Opinions and facts greatly appreciated.  Thx.

[Tatooed_Lady]

arm & hammer baking soda and muriatic acid are supposedly the only thing you need to raise/lower the pH, and at a huge discount over the pH up/pH down.....according to what I hear (I try to keep open ears AND mind), each is the active ingredient in the pH altering products, and on its own, doesn't contain  the "extra" stuff that raises the TDS level so much.
If this is true, I'll be using the cheaper stuff instead.

[cappykat]

I thought I read baking soda and vinegar.  I know baking soda works because I just raised my pH with it.

[Alex1]

Alk up is sodium bicarbonate  ie. baking soda and ph up is soda ash. The ingredients are on the labels. It looks nicer in the spa bottle packaging I guess.

[IDW]

You do not use baking soda(sodium bicarb)to raise ph. It is true that ph will raise when adjusting alkalinity(adding sodium bicarb) becacuse it is a base. Alkalinity is a measure of disolved sodium bicarb in water and really has nothing to do with ph other than acting as buffer  to reduce ph bounce.Alkalinity needs to be maintained at 125-150ppm even if it takes the ph too high with it. When alk is in range then adjust ph. Soda Ash to raise it and acid to lower it.Not vinegar. Muratic acid works but is a danderous product to use. Dry acid is sold in most pool stores. Never adjust ph unless alk is in range. It wont work.
Sodium carborate aka "soda ash" is the same thing. A product to raise ph not alkalinity

[tony]

You do not use baking soda(sodium bicarb)to raise ph. It is true that ph will raise when adjusting alkalinity(adding sodium bicarb) becacuse it is a base. Alkalinity is a measure of disolved sodium bicarb in water and really has nothing to do with ph other than acting as buffer  to reduce ph bounce.Alkalinity needs to be maintained at 125-150ppm even if it takes the ph too high with it. When alk is in range then adjust ph. Soda Ash to raise it and acid to lower it.Not vinegar. Muratic acid works but is a danderous product to use. Dry acid is sold in most pool stores. Never adjust ph unless alk is in range. It wont work.
Sodium carborate aka "soda ash" is the same thing. A product to raise ph not alkalinity

I have to disagree, sort of, just a little.

You certainly can use baking soda (aka spa up, alkalinity increaser, sodium bicarb) to raise pH.  You just have to realize that it will raise TA also.  If your TA is at the high end of normal (around 120), I would use soda ash (sodium carbonate, pH up).  If under 100-120, use the baking soda.  My TA stays close to 80 and tends to slowly drift down.  When my pH drops a little, I use baking soda to raise.  If my TA ever gets above 100, it tends to draw my pH up with it and thus have to keep bringing it down.  As a result, the water comes out of the tap at about 80 and I like to keep it close to there and it stays there with little effort.

I personally would not use muriatic acid in a spa unless you had extreme situations, such as source water with way high pH or TA.  Nor would I use vinegar unless you had the "correct vinegar."  Dry acid is cheap enough and the correct chemical for spas.

For the record, I have never used soda ash, only baking soda to raise.

[Vinny]

I agree with Tony!

The amounts of product that you use in a tub is a lot different than in a pool so use the correct items except for the baking soda. And I do find that Doc has the best prices and service and I use him too.

I do use household products for my pool - bleach, baking soda and borax for PH up but that's 13,000 gallons and my tub is 400.

I've never used muriatic acid and I would be uncomfortable doing so.  I've read it's potent and I would hate to get the tub yo-yoing about or damage it.

Look for bagains, read the labels and purchase the product that'll save you money but make sure it's the correct product. True Story - Walmart sells HTH chemicals for both pools and spas and their spa chlorine used to be dichlor - last year it was calcium hypochlorite, not dichlor- I bet a lot of people who bought that chlorine couldn't figure out why their tub got cloudy and possibly rough.

[Snowbird]

Well, I just learned something... I think.  

We use the Nature test strips that test for mps, total alk and pH.
I adjust mps with Activate.
I adjust pH with pH up and pH down.
But I didn't have any idea how to adjust total Alkalinity or what affect it had on the tub.

So here is the top ten list of things I learned:

10. Sodium bicarb (Baking Soda) will raise total Alkalinity
9. I should not try to adjust pH unless my Total Alkalinity is at the correct level.
8. A correct reading for Total Alkalinity is somewhere between 80 and 150 ppm. (Is this range too big?)
7. The correct total Alkalinity reading will contribute to a more stable pH by reducing the yo-yo affect.
6.  I used muratic acid to clean the bricks on my house and damn near killed myself.  There is no way I am going to sit naked in a tub of it no matter how diluted it is.
5. I think I will leave the Borax for washing my hands after working on the car.
4.  Bleach (Clorox) is okay if my water ever turns a little green but we spent extra money to avoid chlorine.  This will be my last resort.
3. Vinegar is good on salads, fried fish and green beans.  I don't want to go to work smelling like an Olive Garden salad.  Thanks, but no thanks.
2. Never buy tub stuff at Walmart.

and the #1 thing I learned form this post....

The only difference between All Clear Soda Ash vs Rendesvous pH Up is $5.46 per pound.

Thanks for all your help.

[TubbinSoon, now we be tubbin]

I use the vinegar more than the baking soda. I never have smelled it. Only a few ounces in 500 gallons is not going to make you smell like a salad.

Worst lingering smells I got was when I was wet testing and got in the bromine floater tubs. Geez, I kept waking up at night with the odor on my fingers and hands when I would reach for the pillow to move it.

The best part of this discussion is seeing the results of your seaches for a economical solution.

[Tman122]

I to use Baking soda and soda ash only, my source water is 70-80 TA and 6.8-7.0 PH and the sodium bicarbonate (baking soda) does 2 things brings my TA up to 120 and brings my PH up to 7.5-7.6 from here it will slowly drift down with that addition of dichlor (cyanaric acid is a by product of dichlor and drives my PH and TA down) and require 2 more baking soda additions in 4 months.

[Brewman]

Go to a big box home store, or a Fleet Farm type of place and look for the pool section.  They often have spa chemicals too.  There you can often find Ph Increaser and decreaser for way cheaper than those skinny little bottles.  I think I paid about $6 for a #7 jug of each, and the ingredients are the same.  
I need a lot of Ph decreaser to get my alkalinity in line when I change my water- it'd be close to $8 worth of the small bottles.  
And I use just baking soda if I need to adjust my alkalinity upwards.