Acceptable Fill Water?

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bradthebold

Active member
Apr 20, 2020
38
Spokane, WA
I need to do a partial drain to reduce CYA and just got my well water test back. Is this ok to directly fill the pool with? I am assuming the previous owners just used hose water and it looks ok. There is a softener in the house, though I'm not sure it would be ok to pull 10k gallons through it. TA is high, not sure how much of a process it would be to lower that much with acid/aeration. Iron is just under 0.3ppm, which is hopefully ok.


pH 7.9
Total Dissolved Solids (TDS) Est, ppm 290
Electrical Conductivity, mmho/cm 0.48
Cations / Anions, me/L 4.8 / 4.4
ppm
Sodium, Na 5
Potassium, K 4
Calcium, Ca 54.6
Magnesium, Mg 21
Total Hardness, CaCO3 225
Nitrate, NO3-N 6.1 (SAFE)
Sulfate, SO4-S 3
Chloride, Cl 3
Carbonate, CO3 < 1.0
Bicarbonate, HCO3 226
Total Alkalinity, CaCO3 186
Aluminum, Al 0.05
Silica ,SiO2 31.7
Total Phosphorus, P 0.04
Zinc, Zn < 0.01
Total Iron, Fe 0.02
Manganese, Mn < 0.01
Copper, Cu < 0.01
Arsenic, As (Total) 0.0015
Cadmium, Cd (Total) < 0.0001
Lead, Pb (Total) 0.0009
 
Yes you can use that well water but you'll have to do some tricks to get the iron out-

If you’ve got iron in your fill water, use Polyfill to remove it

EDIT: Found out this method only works if your iron is oxidized already, meaning it’s got a dull or bright green tint to the water, or a nasty brown tint. If you know you have iron in your fill water, but it isn’t oxidized yet, bring your pool to shock level and it’ll turn the telltale green...
www.troublefreepool.com www.troublefreepool.com

Maddie
 
If the pool has a sickly greenish cast to it, or if it goes brown like tea, Iron is a problem. Don't freak out if it happens. But I think you'd have seen something by now if the pool has been filled all along with the same source water.

Lowering TA is just going to take a lot of acid. As high as it shows in those lab results, I'd expect the pH to rise almost as fast doing nothing special as going to a lot of effort to devise an aerator. So just resign yourself to daily or every-other day pH adjustments for a little while.
 
I think the pool is pretty blue, maybe with a slight green cast, but I might just be imagining it looking for iron. No brown though and no iron issues in the house. There is a 1.5" fire hose next to the pool for the purpose of filling it I think, so I'm guessing it's fine.

Is there a way to calculate how much acid I would need to deal with 10-12k gallons? At $10/gal for acid, it may be cheaper to find an outside source for water if I need a lot of it. Otherwise I'd be fine adjusting pH at the same time I'm testing and adjusting for FC.
 
bradthebold said:
I think the pool is pretty blue, maybe with a slight green cast, but I might just be imagining it looking for iron. No brown though and no iron issues in the house. There is a 1.5" fire hose next to the pool for the purpose of filling it I think, so I'm guessing it's fine.

Is there a way to calculate how much acid I would need to deal with 10-12k gallons? At $10/gal for acid, it may be cheaper to find an outside source for water if I need a lot of it. Otherwise I'd be fine adjusting pH at the same time I'm testing and adjusting for FC.
Click to expand...
If the pool is 12,000 gallons, 1 gallon of 31.45% acid will lower TA by 42. I think it will still be cheaper to buy acid than to buy a tanker full of water.
 
Ok. Current TA is 110, fill is 186. If I replace 60% of the water, it would be 155. Pool is 20k, so 1 gal of acid would lower it 25, so to get to a TA of 70 would be about 3 1/3 gals of acid, so that's not bad. Going from 7.8 to 6.8pH is only a half gallon though, so it will be a process.

So the fastest I can adjust it would be just keep it above 7.2 when we're using it, maybe a little lower during the week, and aerate with a small submersible pump I have or I'm going to have to get a bigger one to drain the pool anyway. And at least aim the returns up. And I guess I'll have to leave the solar cover off.

How much water can I safely drain without worrying about some catastrophic issue? Current CYA is ~120ish, so I probably need to replace around 60-70%.
 
I am not sure about the water table. The best I could find from a while ago is a well near me had water 88ft down, not sure if that even answers the question. It is going to be 80s and dry the next couple weeks though.

Exchanging seems like my only option, so I will do that. I'm guessing it will take much longer though, since I'll be pumping out at least a portion of the new water I put in. And it defeats the purpose of high flow drain pump since I won't be able fill it that fast.
 
bradthebold said:
I am not sure about the water table. The best I could find from a while ago is a well near me had water 88ft down, not sure if that even answers the question. It is going to be 80s and dry the next couple weeks though.

Exchanging seems like my only option, so I will do that. I'm guessing it will take much longer though, since I'll be pumping out at least a portion of the new water I put in. And it defeats the purpose of high flow drain pump since I won't be able fill it that fast.
Click to expand...
Take a walk around the neighborhood. Any ponds, lakes or creeks at your elevation? Are you right at sea level? Any neighbors got empty pools filled with mosquito larvae? If the answers are no, I wouldn't worry too much. You're pulling out half -- what's that? Three feet down? Things would be pretty swampy if the water was that close to the surface.
 

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I figured I would update. I got a $50 sump pump and ran it with garden hoses to exchange water. I ran it for 36 hours the first time and got the CYA from ~120-160ish down to 70. I ran it for another 22 hours after that and it's in between 40-50 now, which I'm fine with. New test results:

pH - 7.5
CH - 200
CYA - 40-50
TA - 150-160
FC - 3.5
CC 0

So looks like I made it through ok. I lost a bunch of calcium and gained TA as the trade off. I've ordered a bag of calcium chloride and added acid to get the pH down to 7.2 and aimed the returns up to disturb the water more. I'll probably use the sump pump and maybe make some pvc device for faster aeration to get the TA down faster.
 
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