New plaster/diamondbrite, fresh fill

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ulrichsd

ulrichsd

0
May 19, 2014
97
Cincinnati, OH
Hello everyone, I have a 20x40' inground, concrete pool with about 30,000 gallons. I just had the pool refinished about 2 weeks ago. Since then I've covered it, have been adding/testing chlorine, and have added about 2 gallons muriatic acid as the pH is always super high (>8.0)

Here's all my numbers tested this evening:
FC = 3
CC = 0
TC = 3
pH = 8.0
CH = 170 (dropped from 225, common with refinish?)
TA = 60 (dropped from 80, presumably from the muriatic acid)

The PB gave me a form that recommends CH at 200ppm and TA at 100ppm, so I need to raise CH by 30 ppm and TA by 40 ppm.

I have a calculator that says to add 11 lbs of calcium chloride (to increase 30 ppm) and 17 lbs of sodium bicarbonate (to increase 40 ppm). I also have 0 CYA, which I will need to add, but right now I have the cover on so not urgent (?).

Questions:
1. Is there an order to add these? Which should I add first?
2. Should I get the pH down with the muriatic acid to around 7.2-7.4 before adding the sodium bicarb?

Thanks,
Scott
 
The CH drop is not what you would expect, in fact the opposite. The TA drop would come from acid addition.

I would suggest lowering the pH a little, at least enough to get you to 7.8 or just below. You should expect this to rise somewhat quickly with a new finish.

Before you do anything else, may I ask where these numbers are coming from, and do you have numbers on your fill water?

Lastly, did the pool builder/Plaster Installer mention that maintain proper balance was crucial for any warranty they may have to honor?
 
Hello Patrick, thanks so much for taking the time to help me out!

I have a TF-100 test kit as recommended by the forums. I bought it last July, so it is around 9 months old, but it has been stored inside in cool dry place.

The poll refinisher gave me a startup/water-balance sheet - the jist of it said to adjust the ph (to 7.4) on the first day and alkalinity to 100. On the third day adjust calcium to 200 and alkalinity to 120.

After the fill (about 4 weeks ago), I measured everything and was at the first set of numbers: pH = 8.0 CH = 225 and TA = 80, so that is probably close to the tap water. I know from my fish tank that the tap pH is about 8.0.

At that initial reading, the CH was ok, the TA a little low, and the pH way high so I started adding muriatic acid about a quarter gallon at a time. After about 1.5 gallons the pH did drop to 7.2. I retested a few days later and it had gone back up to 8.0 (top of the scale). Since then I've been adding about a 1/8 of a gallon muriatic acid at a time to not over-shoot, but every test has been at 8.0. I know the PB said the finish raises the pH so I'd be dumping in muriatic acid constantly, which has been accurate.

I turned the pump on this morning (right now set to 8 hours) and added about a quarter gallon muriatic acid, so I'll test it tonight to see where it is at. I have about 8 lbs of alkalinity increaser left over from the previous owner so I can drop that in tonight if the pH is good. I can go to the store tomorrow and pick up some calcium chloride to add as well.

I have not yet added CYA as I put the safety cover on to keep out debris and figure that isn't as important since the pool is not getting sunlight. The cover does have some small holes so rain water is probably getting in which might account for the drop in calcium? I probably need to drain some as I can see the water line has gone up a few inches and is at the top of the skimmer.

Initially I was adding liquid chlorine to get the chlorine level up, but I have been out of town for work two of the last three weeks so I set the inline chlorinator with one puck each week or so, which has kept the FC at about 3ppm. Seems to work with the cover on, and not I'm worried about the additional CYA since I haven't added any yet. When I look inside the cover, the water looks clean and beautiful, I can't wait till it warms up a bit and I can take the cover off!

Thanks again!!
Scott
 
Just bought another 2 gallons muriatic acid, 8 lbs calcium hardness increaser, and 10 lbs alkalinity increaser.

I'll go measure the pH and if it is ok I'll add the alkalinity increaser and calcium. If not I'll boast some more muriatic acid.
 
The alkalinity increaser label says that low alkalinity can cause pH bounce, etching of plaster and corrosion so I figured I had better get that back up to 80 ppm first so it is in range. Then go back to lowering pH and lastly calcium hardness (it says not to use calcium hardness the same day as alkalinity increaser)
 
Thanks for the links! Love this forum and all the people willing to help out!

Tested after another hour and ta = 80 ppm so i went ahead and added .25 gallon muriatic acid.

I think I'm going to go ahead and some cya in a sock to the skimmer tonight and get that started.
 

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Morning update: ta down to 70 ppm, pH still >8.2. added another 1/4 gallon muriatic acid.

Will test in an hour and once pH is down i will drop in some more alkalinity increaser. That cya in the sock is going to take forever to dissolve in this cold water :)
 
Tested an hour later and i am:
Fc = 3.0
pH = 7.5
Ta = 80 ppm
Ch = 225 ppm (not sure where i got the 170ppm from as each drop is an increase of 25ppm)
Cya = 0 (not dissolving too fast, sock still full)

Looks like i may need to pick up another 10 lbs of alkalinity increaser tomorrow.

Did some vacuuming as well but it's not too dirty with the cover on.
 

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