Opening Pool with Lake Water

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blistex

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May 11, 2014
12
Dallas, Georgia
Hi, hoping some of you have some ideas for us - we've got a new-to-us 21K gallon inground pool. Sand filter, no idea when the last time the sand was replaced though the pressure seems good. (Vinyl liner, if that matters.) The house is on a well, so the previous owners had rigged up a system to fill it from the lake, but, it's not going so well.

Here's what we've done so far:
Day 1: Took the cover off the pool (which was quite an ordeal, will be purchasing a security cover for next year). Water level was about halfway down, but the water was very clear and there was only a small amount of debris/dead algae on the bottom of the pool. Oh and about a dozen dead scorpions and baby snakes (ick!) which we fished out.
Day 2: Filled the pool with the lake water. Pool was now very full (pool store recommended filling to above the skimmer in case we needed to floc) but the water was yellow/brown and cloudy.
Day 3: began running pump, added shock, added algaecide two hours later. left pump running for 24 hours continuously.
Day 4: Water still bad, brought sample to pool store. I don't have the exact numbers on everything but they said our pH was 7.8, our free chlorine was good, our alkalinity was low, and we had iron & copper in the water. They said the pH was perfect for floc and that could also resolve the metals and cloudiness, so to do the floc that day. Returned home, added floc on recirculate for two hours, then shut down the entire system to wait for the magic to happen. (Note: it rained later in the day, not sure if this is an issue.)
Day 5: 24 hours later, no magic has happened. The pool may be marginally less cloudy, but it's hard to say. You still can't see the bottom at all in the deep end, and you can see it a tiny bit in the shallow end but that may just be because it's very sunny today.

I just went ahead and retested the water with our strips at home. This is what we got:
CH: 200
Total Chlorine/Free Chlorine: .5 (!!)
pH: 7.2
TA: 40
Stabilizer (CYA I guess?): I think this is 0 because the pad is golden yellow and the colors on the comparison chart only go from medium orange to red. So, let's assume 0. Which I think is bad.

Any ideas for what to do next? Is it possible we've still got live algae from the lake water, or...?? Any thoughts at all much appreciated!
 
Welcome to the forum!!

My advice is to stop going to that pool store. You are on a path to spend a fortune on chemicals that will have a dubious chance of being successful in the long run.

Get yourself a good test kit and start reading Pool School. Start with the link in my signature. All the info you need to take care of the pool yourself (and which test kit to get) is in pool school.

I know that's not the answer you were hoping for, but if I started typing all you needed to know in this post, you'd be lost by the third sentence. Order a test kit, read while you're waiting for it to be delivered, and post back with questions you have.
 
Ha, already working on that, but I didn't see anything specifically addressing what else might be in lake water that floc wouldn't handle, or if there is any reason other than live algae that the pool seems to have eaten up all of its chlorine in a single cloudy day. Also not really sure where other than the pool store to get something like CYA, which the pool seems to quite need!
 
Walmart carries HTH brand stabilizer, in 4 lb bottles. While you are there, buy up all the bleach you can, you are going to need it once your test kit arrives.

As Smykowski has noted, you need the proper test kit, and to read Pool School. Best value is the TF-100 with the XL option and speedstir. Read about them in Pool School.

I would wager that you will catch on quite quickly, and have a beautiful sparkly pool in no time, without using floc, or any other "special/magical" potion from the pool store.

We don't trust test strips, they go bad too quickly and are wrong as often as pool store testing.
 
I'll add it looks like there is a SAMs club nearby Dallas in Hiram. SAMs usually have 3 bottles of bleach (regular, not scented or gel) for a good price. As charle_r said, I once you get your test kit you'll need some to get the shock level up and keep it there until the water is sparking and clear!
 
It's always a good idea to test the lake water before using it as fill water. It may end up costing you much more money in bleach and headaches than using your city tap if that's even an option. Like everyone has said, scratch the test strip, forget about the floc and forget about the pool store. I doubt your PH is high and your Alkalinity is low. I also know that your free chlorine is NOT good. You're going to need more chlorine to clear up the pool. That's for certain. Get an accurate test kit in order to figure out how much you need.
 
We're on well water, which is the reason for using the lake - the previous owner said he had the fire department truck out water once and it was roughly the same amount of dirty as the lake so he'd recommend the lake(?) so we gave it a try.

Test kit should hopefully arrive Wednesday, until then I feel like there should be something I can do, but perhaps not. I know test strips schmest strips and all that, but it's a new bottle stored carefully so it seems like at least relative to one another they should be telling me something. Yesterday prior to reading this forum, I added the last batch of shock to the pool (4 lbs of dichlor). Tested an hour later and FC and TC were definitely above the max of 10 measured by the test. tested two hours after that and TC was still on the max range but FC was reading more like 7, so using PoolMath and the SLAM instructions I added a jug of bleach to the pool which got FC right back up to 10 as predicted. Been running the filter throughout all of this, so I went ahead and tested right before bed (still 10) and at 6:30 this morning (still 10) so it seems like not much chlorine lost at all overnight, but the pool looks the same - very cloudy, can't see the bottom, brown with a slightly yellowish tint. I also brushed the pool down just in case.

Another point of possible interest is that it seems like whatever is in the pool making it cloudy is going right through the filter (again not sure how large - it's a 1.5 HP Hayward sand filter, about 7 years old) - the PSI went up only about 2 PSI overnight, was expecting to have to backwash this morning. Going to try to keep SLAMing it at least for the day to see if there is some improvement...
 
Wow, okay, I'd never heard of that. The filter did seem to be filtering before this - PSI went up by about 10 overnight and we backwashed - so it seems more like the particles are too small but if SLAMing doesn't seem to have any more effect today, maybe we'll try that tomorrow. Couldn't hurt, right?
 

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- the PSI went up only about 2 PSI overnight
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PSI went up by about 10 overnight and we backwashed
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I can't make sense of that.

Since you don't report the size of your sand filter I will tell you that it took about 5-7 days for my pool to clear from pond water and it was mostly dirt and not algae. My issue wasn't lack of chlorine but just dirty water that had to be filtred a lot. My filter holds 925 lbs of sand and it still took that long.....I suspect yours will take longer
 
Sorry, I was unclear - Friday night was the night it went up 10 PSI overnight, which was the first night we ran the pump after we filled the pool from the lake. Last night (Sunday night, two days later), same water, pump only went up 2 PSI overnight.
 
Just wanted to update here since it seems from forum searches and replies there's not a ton of experience with filling with muddy lake water!

So, still waiting on my test kit (should arrive tomorrow) but looking at the muddy water was depressing and I was curious what the pool store would say about it since their previous advice did not work. Lucked out and got the one guy who seemed to actually 1)know what he was talking about and 2)care about giving good advice. He was super irritated they told me to floc the pool. He then tested the water and looked at our last test and after a lot of confused hemming and hawing, he said he really wasn't seeing any problem except my pH is high and my TA is low, which shouldn't give me muddy water. He said as much as he hated to say it, he thought maybe we really did just need the flocculant, that it's an overused product but there are occasions for it. Since our pool only takes half a bottle, I had half a bottle still (and time to kill waiting for my test kit) so he thought it was worth a second try. (Bonus for not trying to sell me anything additional!) He suggested letting it recirculate for 3 hours this time and just seeing what happened.

WOW, what a difference this time. Within 30 minutes of shutting off the pump, we could see the bottom in the shallow end and the next morning it was all clear water with a layer of settled sludge on the bottom. I'm sure eventually it would have been filtered, but it could have taken weeks, so, dunno, for $20 and 24 hours I'd say this was one instance where specific pool chemicals were worth it, if anyone else has to fill their pool from a clearly muddy source and no other problems are found. Vacuumed on waste and tomorrow we'll be starting our TFP pool care, but from the looks of it I'd gladly swim in that water right now.
 
Yay, test kit is here! I think things are looking good, but I'm a little unsure about the CC. So, last night in intervals, I added CYA solids, then bleach to shock levels, then 4 lb baking soda because my original TA was 40. Everything looks like it's doing what it should, but I know CC should be under .5 and it's just barely over that. Could the chemicals raise it temporarily (only been about 14 hours since the last addition) or should I go ahead and SLAM until it's definitely under .5? Water looks pretty much clear and pool is a very appealing shade of blue.

Current test results:
pH: 7.2
FC: 10.2
CC: .8 (maybe .7, it was practically clear at .6 but noootttt quite.)
TA: 80

I didn't even bother checking CYA because it was 0 the whole time and I added the solids just yesterday. And, I only bought half as much as I should have so even if miraculously it would register on the test, the test only goes down to 30 and based on PoolMath I only added enough to get up to 20. Planning to go back and get more to add today.
 
blistex said:
Yay, test kit is here! I think things are looking good, but I'm a little unsure about the CC. So, last night in intervals, I added CYA solids, then bleach to shock levels, then 4 lb baking soda because my original TA was 40. Everything looks like it's doing what it should, but I know CC should be under .5 and it's just barely over that. Could the chemicals raise it temporarily (only been about 14 hours since the last addition) or should I go ahead and SLAM until it's definitely under .5? Water looks pretty much clear and pool is a very appealing shade of blue.

Current test results:
pH: 7.2
FC: 10.2
CC: .8 (maybe .7, it was practically clear at .6 but noootttt quite.)
TA: 80

I didn't even bother checking CYA because it was 0 the whole time and I added the solids just yesterday. And, I only bought half as much as I should have so even if miraculously it would register on the test, the test only goes down to 30 and based on PoolMath I only added enough to get up to 20. Planning to go back and get more to add today.
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If it was my pool, I'd assume that whatever CYA I added was already in the water and raise FC to SLAM level for that calculated CYA. That CC is still too high. Keep adding bleach to maintain the SLAM, and when the sun goes down, start the overnight loss test. If it's good tomorrow morning before the sun hits it, and the CC in the morning is below .5, you've passed all three criteria and can let FC levels fall and proceed with normal maintenance. It's only a couple gallons of extra bleach now, but if you stop too soon, it could mean another 20 gallons later.
 
Huzzah, all SLAM tests passed, pool opening is cruising along (and I'm guessing it's swimmable right now but I'd like to get the water totally right before we put the ladders and such in).

Test results this morning:
FC: 8.5
CC: <.5
pH: 7.3
TA: 80
CYA: 50

I didn't bother testing CH this time since it's been in range every time and we have a vinyl liner. I added some Borax to get the pH up a bit and then I'll tackle the TA.

One concern is that based on PoolMath and the stabilizer instructions, I only added enough CYA to get my 21,000 gallon pool up to 40 but it's already registering 50 only 48 hours later. I'm not concerned with the CYA number itself, just wondering if I have the water volume wrong and not wanting to overadd chemicals. I went ahead and added Borax based on a 15,000 gallon pool, figured I could always add more later if it needs it. Just weird since I got the volume from the papers that came with the pool installation so it really should be right, but maybe we have less fill, it's about halfway up the skimmer.
 
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