bicarbonate startup

[anonapersona]

We are just starting to consider a pool renovation. We will probably replaster the pool also.

I know that my tap water had TA 340 last time I tested it, long ago. Given that, I wonder if it would be wise to try to find an installer who is familiar with the Bicarbonate Start Up. With TA of 340 on a fresh fill, it would seem that we are halfway there.

Anyone out there able to discuss this? I realize it may be over my head, chemically, but I suspect that this may be a way to get a great start given my water.

 

[onBalance]

I believe your tap water is already perfect for filling a new plaster pool. But need to know what the calcium hardness content and what the pH of your tap water is?

 

[anonapersona]

The calcium hardness is 20 out of the tap, TA is 220 when recently tested. The pH of the water, after 24 hours, is above 8.2 and I cannot say exactly how much above but I guess maybe 8.3 but I really don't know how to as that is above the ability of the "blue box" to tell me.

But, I am beginning to think that the start up is not going to compensate for the installer adding too much water while troweling. I'd like a darker finish so I might get into the pool a bit earlier in the year, but the darker blue polished surfaces may not look right if they always add water while troweling. I have noticed rather a lot of SW Texas and Houston area pool with plaster issues that seem to be due to excess water while troweling.

 

[onBalance]

If the TA is 220 ppm, then I think the pH is right at 8.3 - 8.4.
You are right, colored plaster jobs are prone to mottling, especially blue pigments, and especially when adding water while troweling.
But a Bicarb Start-up would definitely improve the chances of less mottling.

 

[anonapersona]

In looking at the Bicarb Startup info I see that I might have a choice of either adding a lot of baking soda or perhaps adding calcium.

I read the start up instructions for Diamond Bright posted online and see that they discuss the effect of using mix water "that has high hardness of alkalinity will cause the plaster to effloresce, releasing salts that cause calcium scale." and they say to NOT add calcium chloride at the start, only adjust TA to 100 ppm which will be difficult starting with TA of 220 or thereabouts from fill water. Then these directions say to adjust calcium on the 3rd day. Not that I am sure I may use Diamond Bright, but I found these directions to be interesting.

I have to wonder if this is what is happening to the other pools locally. Perhaps high alkalinity inside the mix is an issue. Though your original pools with high calcium water stayed dark, not creating dust. I sure don't know.

Meanwhile, I quizzed the plaster company owner and he explained that the crew will work with a trowel in one hand and a wet paint brush in the other, brushing the plaster with water as they trowel it to keep it somewhat damp as they work the water out of it as the mixture sets up from the bottom. This is how they are trained to work. All of his crews have at least 10 years with him.

My pool was originally done in light grey plaster. It is very mottled and I cannot tell whether the plaster is dark grey under beige calcium deposits or whether this is the gunite I see. I did a 50% acid mix in a squirt bottle and put some on the step of the spa where it fizzed a lot and a soft grey cloud developed at the surface. Under that is a deeper grey surface that contains darker bits, almost like a black sharp sand. The pool built in 1999.

 

[onBalance]

Diamond Brite people are concerned about calcium deposits, but are incorrect the "high hardness of alkalinity" causes the plaster to release salts and effloresce.

Yes, you could add calcium chloride as it fills, but that can be very tricky.

It is sad that some plasterers of today aren't aware that in the cement/concrete flatwork industry, they don't have a water brush in the hand. They usually they have a second trowel. With that being said, if the plasterer only uses a few drops of water to lubricate their trowel, they would improve their chances for a good job. But it is known that water troweling on colored jobs is especially not recommended. And if they would just not add calcium chloride to their mix, the plaster wouldn't hardened so fast and they wouldn't have to add water to keep it workable! They would be able to trowel at the right time without using any water! Cooler days help as oppose to hot days too. If it is hot, they should put up tents.

Fizzing (acid treatment) will always occur on calcium scale and the plaster itself, so it is hard to tell which it is. But it sounds like probably some scale on the surface.

 

[anonapersona]

What does gunite look like? is it deep grey with black flecks?

 

[onBalance]

Yes, gunite is dark grey, and usually more sandy, gritty, and brittle than pool plaster. It can have black flecks in it, and would also fizz if acid is applied to it.

 

[anonapersona]

Ah, so we are likely down to the gunite then. Well, guess we will be signing a contract for replaster tomorrow. Now, I have some 3 days to decide on a finish.

So, back to the bicarb startup. With fill water of 220 TA and very low CH of perhaps 20, I see that the Bicarb Startup directions say to use baking soda to get the sum of TA and CH to 500. That would drive my TA to 480 which would mean a ton of acid to attempt to drop it back to the 70 to 80 that it takes to keep pH in check in my pool. That sounds like going from a bicarb start to a hot acid start, back to back. Crazy. So it must be that I don't do that and just fill the pool with tap water, then adjust the CH to something like 280 ppm as fast as possible once the pool is full.

But, the Pool Calculator says that although with a TA of 220 and CH of 20 and the resting pH of my tap water about 8.3 the CSI is near zero, as I start adding CH the CSI gets too high pretty quickly, as in with CH of 250 and any pH above 7.9. Is this likely to happen? Won't the pH be driven way higher than 7.9 due to the chemistry of the setting up of the plaster/cement? I am too aware that the original owners of this pool had a quote for a replaster in the file only 3 years after the finish was installed. Perhaps it scaled up during the start up?

 

[onBalance]

As you suggested, it is a better plan to just fill with your tap water, than do an acid start-up. And then adjusting the CH upward as quickly as possible to 250 ppm, but not any higher. With 220 ppm of TA, that will suffice good enough. Just make sure you add acid first to get pH down below 8.0 before adding the calcium chloride. You do want to slight positive CSI for first few weeks, +0.3 to +0.7 will work.

In regards to the pH going higher because of the new plaster, the answer is no. If the TA is 220 ppm to 250 ppm, and the CH is 250 ppm, then that will stop the severe high pH problem and the scaling issue. There shouldn't be much problem with that plan. Just to let you know, I have never come across the type of tap water you have, so that is new and strange to me. So due to the strange tap water you have, adjustments to the Bicarb start-up program is appropriate. Since the CH is so low, I think it would be beneficial and smarter to raise the CH rather than raising the TA to 450 ppm.

I haven't seen pictures of your pool, so I don't know what may have occured when your pool was first plastered.

 

[anonapersona]

I know the plan it to use StartUp-Tec when the pool is first filled. It has sequestering agents and polymers, I cannot tell what else may be involved. It claims, and the installer believes, that it greatly reduces plaster dust. The instructions there say to fill the pool using the proper amount of the product. After filling, lightly brush and brush vac and balance water per National Plaster Council guidelines, whatever those are. I assume due to the order specified, they mean to brush and vac before balancing water.

 

[onBalance]

Generally, Startup-Tec can reduce plaster dust, but not always. It is better than doing nothing, and better than an acid startup. So I hope it works for your pool.

NPC guidelines are TA 80-100, minimum CH is 150 ppm at start, then raise to 200 ppm by one month time, and Ideal pH of 7.4 to 7.6. Yes, brushing and vac is important, but be sure to brush afterward vacuuming so that you "un-stick" the plaster dust due to the vaccum wheels tamping down the plaster dust. Otherwise, it will stick to the plaster and become harder to remove later.

 

[anonapersona]

Thanks for the NPC guidelines.... How does one get to those guidelines from where I start? Is one supposed to fix the fill water BEFORE it hits the pool, as you do with the bicarb startup by using the barrel and hoses, or is it OK to wait until the pool is full? Given that my tap water is pretty much neutral CSI after entrained CO2 is outgassed by resting I will guess that it is OK to start in the morning.

Playing with the Pool Calculator to see how this might go.... Assuming I need to take small steps, watching the CSI on the calculator all the way to keep between +0.3 and +0.7 per your direction. But, that high on the CSI?? The Pool Calculator says that is a scaling danger zone. I think I can keep it between +.03 and +0.5 if I take small steps.

Is doing this in a single step OK? That is, add 50 oz acid to get pH from the expected 8.3 to 7.8 and add calcium chloride to get to 150 right after. CSI = +0.3 then. I know that the circulation of the pool, spilling over the spa, will drive the pH up. So I must not let it get over 8.0 to keep CSI at no more than +0.5.


The spillover from the spa will be driving the pH up all the time due to the high TA. Using the automatic chlorinator will help combat that to some unknown extent. I have observed TA drop by the same amount that CYA rises but that is just observation. What I don't know is how far pH might try to rise overnight.... do I have to wake to test the pool?

At some point I add stabilizer to get to maybe 20 ppm, probably in the skimmer so I do not get any on the plaster. Then begin the automatic chlorinator. Use that until CYA gets to 30 ppm which is only 10 tablets of trichlor. That will take maybe 10 days using up one a day or so. In that time TA may drop by 10 ppm due to tablets. I'll still be adding acid anyhow so after every second acid addition I will retest TA. (need to be sure I have those testing chems in excess)

Continue testing and adjusting pH daily for months and months. Slowly get CH to 250 - 350 ppm while watching the CSI to keep in proper range. Probably will switch to using cal-hypo for chlorine needs as each 8 oz gives a day's FC of 2 ppm and a bit of CH at 1.3 ppm. Daily use will add 10 ppm CH per week.

Needless to say, the plasterer is not going to do the startup. I will keep good records so we can know what happened. I noted that both pools he showed us, he blamed the pool owner for poor start up procedures or lack of brushing during startup.

 

[onBalance]

The NPC start-up waits until the pool is full. (They should know better). The pH of the pool water is likely to be above 8.4 once filled with water. So more acid may be needed than you plan to add.

As long as the pH is below 8.2, a +0.7 isn't a problem, but if you want to keep it at +0.5, that is fine.

If you follow the acid demand test, add the acid, allow to circulate and dissolve, confirm the lower pH (7.6), and then can add the full dosage of CC.

Waiting over night is okay, so sleep all night. In fact, in the case of new plaster, a low TA will actually allow the pH to rise far quicker and higher than when the TA is high (like your water is). The pH of your water shouldn't change too drastically over night because of the high TA. Yes, that is just the opposite of normal situations with older cured plaster. (There are always curve balls to deal with).

It would be wise to video the plastering and the adding of the CC into the mixer.

 

[anonapersona]

The NPC start-up waits until the pool is full. (They should know better). The pH of the pool water is likely to be above 8.4 once filled with water. So more acid may be needed than you plan to add.

As long as the pH is below 8.2, a +0.7 isn't a problem, but if you want to keep it at +0.5, that is fine.

Then, at pH 8.5-ish per the Pool Calculator.... CSI is still OK at +0.2. I see that even up to pH = 8.9 CSI still < 0.6. Not what I would have expected.

If you follow the acid demand test, add the acid, allow to circulate and dissolve, confirm the lower pH (7.6), and then can add the full dosage of CC.

Waiting over night is okay, so sleep all night. In fact, in the case of new plaster, a low TA will actually allow the pH to rise far quicker and higher than when the TA is high (like your water is). The pH of your water shouldn't change too drastically over night because of the high TA. Yes, that is just the opposite of normal situations with older cured plaster. (There are always curve balls to deal with).

It would be wise to video the plastering and the adding of the CC into the mixer.

Not sure what an acid demand test is. I will test pH and use the Pool Calculator to determine the acid needed to get to 7.6 if that is what is needed. Brush with the Wall Whale to mix the pool well, then retest ASAP to confirm the pH at 7.6 (CSI = -0.7 with CH still at 20). Then add Calcium Chloride to get to 150 ppm.

I don't understand the suggestion to video plastering and adding CC into the mixes. You mean to document the amount of water they actually trowel into the plaster with those brushes? and what mixer do you mean.... when I am diluting the CC to add to full pool? There is to be no CC in the plaster -- I will take the 50 lb bag he brings for my use and hide it.

 

[anonapersona]

Meanwhile, I have a call into the water authority to confirm my calcium hardness and total alkalinity testing.

 

[onBalance]

The Calculator will work to help you on how much acid to add.
Yes, the video will record where and how much water troweling occurs. After a few weeks, you may see a correlation on certain areas of the pool. The video is not for when you add CC, it is for seeing what goes into the plaster mix. You will probably make them nervous.
The mixer is on the rear of their truck and is used to mix the plaster. If the plasterer has agreed not to use CC, then that is great. They shouldn't use any. Yes, if you find CC on the truck, take it and hide it. Tell them to take some extra time to trowel it right.

 

[anonapersona]

I will get the installer to sign off on the "No CC" on the contract and then get set up to video as you suggest. And after reading at length about StartUp-Tec on their site, I see that the plan is a little short on the bottles planned for, as I calculate 23000 gallons total volume which includes the spa and piping. I will see that he has the 3rd bottle the site says is needed.

Meanwhile, I called the water authority to confirm my water testing and, yes, the CH is about 25 - 30 ppm and the TA is about 250 - 260 as of 2010 testing. She said it does not vary too much over time so these numbers are basically correct. I suspect that my testing is valid, at CH about 20 ppm and TA at about 220 ppm. All of that is within the testing error for the TF-100 and the normal variation from time to time and place to place that they test.

 

[Terry]

Did you go with the bicarb start-up? If so, what did you learn?

 

[anonapersona]

Did you go with the bicarb start-up? If so, what did you learn?

They are plastering today. I went with a not-dark plaster. Though I really wanted the Smoke Quartz, someone else in Houston had issues with it during pollen season and I suspect that this is why my medium grey plaster was beige/yellow overall. As they chipped around the fittings, I was stunned to see that my plaster was fine, just overlain with a beige/yellow film. Probably an acid wash would have been suffucient. Too many people had suggested that the grey I saw was gunite. Turns out the gunite looks like dog poo, the plaster was like dark grey cement. Anyhow, since I rather like the turquoise color the pool was, I chose a quartz finish that looks most like what the pool had become, which is Jade (plaster with turquoise, grey and a touch of black quartz.)

I have already lost the CC battle, did not get that in writing. Caught them adding it, and called the owner who said that due to cool temps (70 degrees) we must use some. No idea how much was added. I will get a sample to test later if that becomes an issue.

Currently in contact with the CLI rep for start up instructions. By phone we discussed that since my heater is inline and cannot be isolated we do not want to go below pH 7.0. However, the NPC guidelines he sent says to adjust alkalinity to 80-100 ppm before anything else. Given that I will fill with 220 TA water, getting to TA of 100 ppm in one day without a hot acid start is impossible. We will speak by phone later this AM.

One question I have at this point; NPC guidelines first talk about Alkalinity, then later stress Carbonate Alkalinity.... I can measure Total Alkalinity but do not know how Carbonate Alkalinity is different, or how it is determined.