Bicarb startup with quartz

Jump to latest Follow Reply
T

Terry

0
Jul 8, 2008
130
Dallas, Tx
I have a new pool going in with QuartzScapes Super Blue (white plaster with blue quartz.) I’ve been reading about the different startup methods and am interested in, what I perceive to be, the benefits of a bicarb startup.

In reading the threads on this procedure and I’m a little confused about the acid washes that are done on quartz finishes.

Are acid washes common? I read one thread that discussed exposing the quartz via a particular method of troweling. Is this the exception? I imagine the plaster company my builder uses has their method, and I don’t suppose I want the practicing a new one on my pool, just curious how common the acid wash vs troweling methods are.

Do they typically do an acid wash immediately at completion, or is the exposure accomplished via an acid startup?

If they do an acid wash does that preclude a bicarb startup; ie, is a bicarb startup of any value after an acid wash or is the damage already done?

Thanks in advance!
 
Some plasterers do a acid wash before filling, and some do an acid (bath) start-up after the pool is filled.

The reason that some plasterers do an acid treatment on quartz finishes is to bring out the color of the quartz aggregate. They do that to remove the cement cream left on the surface. However, that ages the pool finish by etching it. My plasterer troweled properly and did not leave any cement cream on the surface. I did a bicarb startup, which help create a smooth, hard, dense surface that had great color.

Whether the plasterer acid washes after they plastering is done, or do an acid start-up after the pool has been filled with water, creates a more porous surface. Yes, it brings out the color of the quartz, but as I stated above, it ages the pool a few years, and sooner will need to replaster.
One can do a Bicarb start-up afterwards either program, but there is very little benefit at that point in doing one.
 
Another thought, I have a natural stone spillway on the spa, and a flagstone beach entry. Would the high TA be harmful to the natural stone in any way?

Ran my fill water numbers: pH 8.0, TA 110, CH 130. Don’t have iron or copper results, but it is city water.
 
I talked to the builder and they do not do an acid wash or acid start up on the pool. They will trowel finish the plaster. However, I am not sure if they will wait 6 hours prior to starting the fill as the builder was concerned it would affect the cure. If the water is started right away, does that negate any benefit to a bicarb startup?

Assuming not, my fill water readings are:

pH 8.0
TA 110
CH 130
Temp ~60

I do not have iron or copper readings, hoping to get them on Friday. Is the point of knowing the copper/iron levels to know whether or not to add a sequesterant, or do they effect the recommended levels for TA, CH, etc?

Playing with the Pool Calculator, if I up my TA to 370 I am going to have to watch that pH very carefully to prevent scaling, unless I’m missing something? Is there any benefit/ option (maybe due to the colder water??) to run the TA a little lower so I have some room for forgiveness with the pH? I guess what I’m asking is am I shooting for an ideal CSI range, or is it specifically having that high combined TA/CH reading that benefits the plaster.

I understand using Trichlor during this process will help with the rising pH. How would it be best to go about this: tabs in the skimmer, in a floater? Any benefit to one over the other? I do not have an auto feeder.

Should I run the filter 24/7? For how long? What speed? I have an Intelliflo.

Is brushing a part of the bicarb startup? If so, how often?

I think that should do it for now. :) And, a thank you to Jason for his reply, thought I had replied to that, guess it didn't go through.
 
I am glad the plasterer doesn't do an acid treatment. Good for him.

Try to negotiate for at least a couple of hours to start the water. Explain to him that the deep end is the last to harden and needs time. There is an ACI cement study that confirms the need to wait several hours before submerging in water. Of course, I have done my own study and confirmed that. Waiting to fill is as beneficial as a Bicarb startup.

Raising the alkalinity to only 300 ppm will work just fine. Just keep the pH below 8.0, which shouldn't be hard to do for a few weeks, until you lower the TA back to normal.
Tabs in a floater works best. I am not sure what the TFP recommends, but run the filter at least 12 hours each day. And yes, brush, that is always important.

I am concerned that the plaster finish will have a blue pigment color added. That color is very prone to streak and mottle, especially if they add calcium chloride to the plaster mix, and water to the surface while troweling at the end.
 
Thank you for the quick response. There will be no blue pigment added, the plaster will be white with blue quartz added. I was under the impression that it was to be Quartzscapes brand, but apparently they will just add quartz to white plaster. Since there is no pigment is the use of calcium chloride and water during troweling still a concern?

I would be interested in the ACI study. I'll try googling it after I post, maybe it will be helpful in persuading the builder that waiting is ok.

The 55 gallon barrel, can it be open on the top, or does it need to be a sealed drum with just the bung holes?
 
Glad to hear that no blue pigment is added, and Calcium chloride and water troweling will be of less concern, but should be minimized as much as possible.
There is very little on the ACI study, but here is what I can give you. Van Aardt, 1953, Discussion of FE Jones on the Physical Structure of Cement Products and its Effect on Durability. The ACI "Guide to Curing Concrete" references that study by Van Aardt, and states that early ponding with water is not recommended because can dissolve cement and from a concrete surface and cause early deterioration.

Here is a link to my study; http://www.poolhelp.com/SIN_ReprintFillDelayArticle.pdf
It was published in Service Industry News, but is a difficult read.

I am going to post another write-up on these issues that I have already written and that is a little easier to understand, so check for that.
 
I spoke with the plasterer at great length today. He has attended several of your meetings through the Plasterers Council and was familiar with who you are, though not necessarily the bicarb startup method. I explained what it entailed, the benefits as I understand them, and he did not disagree with any of the premises.

I confirmed that he does not do any type of acid wash or acid bath.

Depending on the temperature of both the air and substrate (gunite) he will alter the amount of calcium chloride he uses, but never exceeds 2%. Given that we are expecting to plaster my pool in the next couple weeks (~80 deg) he would expect to use .5-1%.
For water addition I have "25 gallons to each 1000 batch" written in my notes from our conversation. I assume I meant 1000 POUND batch? I don't know how to convert that to the numbers I read in your publications.

I did hit a road block at the length of time before water is started. I explained to him what you said about the walls having time to cure before water hits them, while the bowl is the last to be finished yet first to receive water and he did agree with that. The reason he likes to start the water right away is that our often high winds cause the plaster to dry out and create craze cracking. This in itself is not a problem as the water will cause it to swell and close back up (?not sure I remember that correctly), however dirt often accumulates in the cracks and then becomes trapped/visible upon cure. We did discuss optimum conditions, where he would be more open to waiting 6 hours: Low wind, 60-85*, overcast, high humidity. Meh, maybe we can pull that off, if we rescheduled several times, and then get lucky. I also suggested starting later in the day so we avoid the bright sun if we don't hit an overcast day. By the end of the conversation the road block was more of a speed bump, so I guess we'll see what happens.

If you have any comments on the above plans please let me know. He seems very flexible, and to genuinely want to create the best plaster job he can rather than dash in and out, cashing the check.

We did briefly discuss that mottling can occur with white plaster due to moisture getting trapped in the plaster. He mentioned Metamax as an option to assist with that. I know nothing about it, and haven't begun researching it yet, what is your opinion?
 

Enjoying this content?

Support TFP with a donation.

Give Support
If the plasterer only adds .5% to 1.0% of calcium chloride (CC) to the weight of cement only (not including the weight of sand aggregate or quartz), that would be good. I assume the plasterer is aware that a one-pound coffee can would actually hold about 1.9 lbs. of calcium chloride (I am going by memory, so I might be off a little). So keep that in mind. That means only adding about two coffee cans worth of CC to 4 bags of cement (do not include the quartz aggregate).

The amount of water added also applies only to the amount of cement used, it does not include aggregate (sand, marble, or quartz).
Twenty-five gallons of water to a 1000 lb. plaster batch is too much. Assuming that he is talking about a 4 to 6 ratio of cement to aggregate, four bags of cement only totals 376 pounds. Therefore, only 22 gallons of water should be added to that amount of cement. That would equate to about a .49 water-to-cement ratio.

I agree with the plasterer that wind is a serious issue to deal with. However, if he has experienced some major cracking in the past, perhaps part of the problem is due to adding to much water to the plaster mix. That also contributes to shrinkage (and also a high content of CC contributes to that too). If it is windy, I suggest getting a large plastic tarp and sandbagging it over the top of the entire pool to protect the new plaster from the wind. That is a good practical solution, rather than starting the water early. Besides, the walls won't get submerged in water for many hours, so what will protect the walls when the wind is blowing?

MetaMax is a good product, but it is not a cure-all. Also, important is using a low water-to-cement ratio, a low amount of CC, and minor trowel lubricating with water at the appropriate time helps provide a quality pool plaster. And a plastic tarp will help keep the humidity in to help with a proper curing before the water submerges the plaster.

Mottling is not "moisture getting trapped in the plaster." Shall we realize that the plaster becomes submerged in water? All the better reason to allow the plaster to dry and hardened before starting the water.
A darkened mottled plaster is most often caused by a high content of CC, and late hard troweling.

You may want to read this: research-reveals-need-for-pool-plastering-standards-t57338.html
 
I talked to the plasterer today, you are correct that the ratio he gave me for the calcium chloride is to the cement only, and the ratio on the water is to the full batch. He does use 4 to 6 cement to aggregate.

We discussed the water quantity, he explained that the way they add water is to take a 5 gallon bucket and dip it in a 55 gallon drum of water then sling it into the mix. He felt pretty confident that they end up losing at least a ½ gallon/ bucket to splash out and not getting the bucket filled completely, so we probably are closer to 22 gallons in practice. I have mixed feelings on the issue; obviously I want the best plaster job possible, that said, I do not want to create working conditions that they are not familiar with and end up with other problems because they had a mix that behaved differently than they were used to.

I’m very happy that they do not do the acid wash, and that their cc quantity is in line- and it doesn’t sound like we’re too far off (and maybe not at all) on water. He is willing to tarp the pool if weather conditions warrant (ie dry, windy day), but I should get a delay on water start regardless. Would you recommend keeping the tarp on until the pool is completely filled, or just for the 6 hours until we start the water?

I am going to set up and test my fill barrels this weekend. I have secured 2) 30 gallon drums from a local car wash. They previously contained ‘high pH presoak’, of course I will rinse them thoroughly. Should I be using a cleaner of some sort, or just water? And is there any reason I need a 55 gallon barrel specifically? I am assuming I can divide my bicarb between the two 30 gal barrels and have the same effect?

Since I am cutting a hole in the top of the barrel, is there any reason I can't just drop the fill hose in from the top as opposed to tapping in from the side? One less place to leak, and one less fitting to buy.

Thank you for all your help on this. Depending on weather we should be plastering next week or the following. I will document the process thoroughly.

Oh, and what is “technical grade” sodium bicarbonate? Where would I find it, and why is it better than Arm & Hammer (or is it the same?)
 
I am glad that your plasterer is going to let you to a Bicarb start-up, and allow for a delay in filling. Pretty good!

Keeping the tarp in place until the pool is full would be best for protection from wind and beneficial for curing to the plaster that is still dry until submerged.
Just use one 30 gallon drum with half of the Bicarb. Just try to prevent the Bicarb from dissolving into the pool too fast. Once the pool is half full, then add the other half of the Bicarb to the drum.
You can drop the fill hose into the top, just make sure it doesn't stir up the Bicarb too much and too quickly.

Technical grade sodium bicarbonate is what you want to use, and should be less cost than "food grade" sodium bicarbonate. But it is essentially the same "stuff." Industrial chemical companies sell that type.

If the plasterer stays on top of the plastering process, tents the pool, there won't be much need to sprinkle and add any water while troweling.
 
So, technical grade sodium bicarb may be what I want, but I’m not sure it’s what I’m going to get. I’ve been trying for several days now to find a distributor for this chemical, with very little luck. I did find a mfg in the area, but they won’t retail. They connected me with a pool co that purchases the product, but they only service large commercial pools/ waterparks and won’t sell the sodium bicarb. I’ve tried janitorial supply, lawn and garden, feed stores, all to no avail.

Anyone in the DFW area have a source for technical grade sodium bicarbonate?

What exactly is the difference? A quick google search shows the addition of tricalcium phosphate to the food grade, but my box of Arm & Hammer shows 100% sodium bicarbonate. Am I trying to avoid additives, or is the technical grade a coarser/slower dissolving product?

I also failed my first attempt to set up my barrel (leaks), so I’m pretty sure I do not have the fittings that you recommended. Do you have any pictures of the fittings you use?
 
Thank you for the link. I didn’t understand that I was looking for sodium bicarb sold in pool stores, I suppose I thought technical grade was different- hence the industrial chemical co recommendation. Which again begs my question, how are they different?

I estimate my pool at 20,000 gallons, and was planning on 67 lbs to raise my TA to 350. I can get five 13.5lb bags of Arm&Hammer for 28.00. I would need two of the 50lb bags from the link for 85.00 + a drive to the other side of the city. Additionally, one of the janitorial supply companies called me back this afternoon and can get me USP Grade (used in the mfg of medicine) for 70.00 for 100lb. They aren’t close either, but it appears they have the purest of the 3 options if purity is the goal.

If I knew how they differed, I’d be able to make a more informed decision here. Obviously the A&H is the cheapest (and closest) option, but if there’s something about the pool supply bicarb, or the USP Grade, that makes it much better (slower dissolving, more pure, etc) I am willing to pay the extra and suffer the drive. I’d just like to know what it is that makes it preferable.
 
I suspect that the pool plasterer can get you a 50 lb bag or two if you offer to pay him for it. During my replastering, they were scooping bicarb from huge bags that looked like 40 - 50 lb.
 
I am sorry for the confusion. I forgot that chemical companies don't sell retail.
There is virtually no difference in the composition, solubility, or anything else. Food grade, USP, A&H, and Technical grade will all work perfectly.
Just purchase the cheapest or easiest to obtain. Yes, pool stores have it, Walmart might sell it, and even the plastering company might sell it to you as suggested above.
 
Thank you for the clarification. I picked up 5 bags of A&H at Sam’s, worked out to be both the cheapest and easiest.

The plasterer came by and looked at the job. I have 2 faucets in the back yard and he wants to run both to fill the pool. How would it be best to do this, both hoses filling one barrel with additional output hoses? Set up the second 30 gal barrel and put ¼ of the bicarb in each barrel, refilling both barrels when pool half full?
 
Any combination would work. But I think the easiest thing to do is to just use one barrel for dissolving the bicarb into the pool water and the other hose can just go directly into the pool at the same time. Won't need as many hoses and fittings.
Easier to monitor, etc.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply