How to "neutralize the acid"

[gregk]

We have an IG gunite ~ 12k gal pool. Resurfaced last year, had some splotching and calcium build up, so we just had it acid washed. We are refilling the pool now. The pool person set to add 7 gal of muriatic acid, let it sit for 24 hours, neutralize the acid, and then start the equipment and pool. This is to get rid of the calcium build up.

I wanted some advice on neutralizing the acid. Do I just use baking soda until my pH is in range? Or is it more complicated (do I need to monitor alkalinity as I do this)?

[CarlD]

The calcium SHOULD neutralize the acid, but....do NOT add anything without a full set of tests:
Free Chlorine/FC
Combined Chlorine/CC
pH
Total Alkalinity/TA
Calcium Hardness/Calcium/Hardness/CA
Stabilizer/Cyanuric Acid/CYA

A new pool that needs acid usually need CYA as well. Therefore, a good all-purpose tool is using Tri-Chlor as your chlorine for a while. It will add chlorine, acid and CYA which you will need.

You don't need to "neutralize" the acid if your pH is correct--in the 7.3-7.8 range. You don't need to worry about it even if it's 7.0-7.2.

Your goal should be to have your TA in the 80-125 ppm range--baking soda does that, but has little effect on raising pH. But too high a TA is bad for a concrete pool. Vinyl is less sensitive--you could go to 180 to 200 with vinyl.

You need to measure Calcium as well--you want your calcium to be at least 200ppm but no more than 400ppm. Again, vinyl owners don't worry.

Chlorine and CYA are a balancing act and you can look up the "Best Guess" table here for correct combos.

But don't just assume you need to add acid, then "acid neutralizer" to your new pool without testing pH--pH tells you what you need to do.

For raising pH, many people here use ordinary 20 Mule Team Borax--it raises pH, without adding to the TA , is relatively safe to use, and is cheap, and available in the detergent section of any supermarket.

For raising both pH and TA, you use soda ash--"pH UP" at pool stores--very expensive. But, next to the Borax is Washing Soda (also Arm&Hammer) which is the same thing as pH Up, but even cheaper than Borax. Don't confuse it with Baking Soda--Washing Soda is in a Yellow box, not an Orange one.

I rarely use it because I rarely have to raise my TA, and I use Baking soda when I do.

Be forewarned: TA rises when pH rises, and falls when pH falls, so adding Borax will cause TA to rise, but (and I KNOW this is confusing) it's not actually increasing TA. Soda Ash, on the other hand will increase TA as well.

It's very easy to raise TA, but darned difficult to lower it, so you measure TA when pH is normal.

I hope this all helps. Most importantly, if you add chemicals without testing you will be very, very sorry very quickly.

Wal-Mart has a cheap kit that tests everything, but has a limited chlorine test.

Taylor sells its K2006 kit which is everything you need. Leslie's on-line sells the equivalent "FAS-DPD Chlorine Service Test Kit." Expect to spend $60 to $80 on such a kit and it's the best bargain you ever get on your pool--especially a nice, new inground concrete pool that you spent 5 figures on.

TroubleFreePools also sells a similar kit, but I haven't any personal experience with it.

Also, as a new pool owner, pool stores will see you as sheep to be sheared, so don't get "Pool Stored". They'll warn you about scary things like "Total Dissolved Solids" and "Phosphates". It's all nonsense that we've seen here year after year. Phosphates and a "Phosphate neutralizing annual contract" are the latest scam. 99.9% of the time ANY problem can be fixed without worrying about Total Dissolved Solids or Phosphates. They will also tell you Bleach is bad for your pool. The only thing bleach is bad for is their profits--and most sell liquid chlorine which is nothing more than bleach.

Good luck!

[waterbear]

YOur pool was just acid washed which should have gotten rid of the calcium! That is one of the purposes of acid washing. By adding 7 gal of acid to your pool they are in effect doing a second acid wash. Sounds a bit strange to me. I would use washing soda (soda ash) to bring the pH back in line and I would use a testkit with a base demand test (like the Taylor k-2006) to see just how much to add. Once the pH is in line you can procede with the rest of your water balancing!

[gregk]

(I have this post on TFP also)

I have Ben's test kit and am testing pH as I go.

I am netralizing now. I started with the jacizzi first, and did overshoot the pH. The water is now milky, so need to figure out the next step. Do I just filter this, pump it out and start over or something else?

I added one box of washing soda to the pool, and the pH is still very low, but it does seem to make a cloud where I added the washing soda.

Any suggestions are appreciated.

[gregk]

I should add, my fill water CH is 190.
I measured the current pool water CH around 250.

[aylad]

Did you measure your alk before beginning the chemical changes? Also, if you put the washing soda in the pool, it's going to be cloudy for awhile until the filter has a chance to filter it out. Usually you should add the chemicals (except acid) through the skimmer, and that will help eliminate the clouding. Keep the filter running and brush frequently to stir up any powder that may have settled on the bottom of the pool. That should help in clearing up the clouds. I would add any remaining soda ash through the skimmer instead of directly to the pool.

As for the jacuzzi, if you've overshot the pH, then you probably will have to add a little acid to bring it back down again, depending on how high it is. Does the jacuzzi water spill over into the pool or is it a stand alone jacuzzi? If it shares water with the pool, I'd probably leave it alone for now and see if the water exchange helps lower the pH again.


Janet

[gregk]

Thanks.

My alk is very low. The TA solution starts dark blue green and turns red after 2 drops. So TA is 20. I have Washing Soda and Borax.

So I am draining the jacuzzi and refilling. I am adding Borax through the skimmer for the pool. I am a bit nervous running the equipment with the pH low, but I am going to keep adding until the pH gets close to normal.

Sound OK?

[aylad]

I am a bit nervous running the equipment with the pH low, but I am going to keep adding until the pH gets close to normal.



Yeah, I know what you mean, but in this case you really don't have a choice--the best bet is just to raise it as quickly as you can. Once you get your pH in range where you want it, then you can use baking soda to get the TA up.

(Sorry about that last post, it took a couple of edits before I got it right! :) )

Janet

[waterbear]

predissolve the washing soda (keep the solution fairly dilute) and walk it around the pool. This should minimize the cloudiness. You are preciptiating out some calcium carbonate most likely. Not that big of a deal and it will fiter out eventually.

[gregk]

Thanks for your help. I usually only need to add acid, so I forgot about using the skimmer for most chemicals.

It is looking good now. The pH is still slowly rising and is around 7.5. I have acid on hand and am monitoring it closely.

Next will by TA, CYA, and adding salt. We knew we would be acid washing during the winter, so I didn't add the salt last year. We definitely misssed the SWG.