First time pool owner, measurements out of whack, now what?

[kmdigital]

I just bought a house month ago with a 21k IG Fiberglass pool, with motorized water proof cover that's about 10 years old. I didn't really want a pool, but it's there, and it's very nice, but the previous owner (PO) only used the trichlor tabs, and was constantly shocking the pool. I've spent a bunch of time reading here, and ordered the TF-100 test kit, which I got last week. He had the K-2005 kit, but some of the reagents were low or out, plus the FC was too hard to read for me, and trying to accurately match the colors.

I knew the CYA would be high, due to years of trichlor usage, but since TA was also very high (~240) so several times while vacuuming I wasted it and lowered the water about 8" and then refilled it with softened water. Sat I tested and here's what I had.

FC = 3.5
CC = 0.5
TC = 4.0
TA = 190
PH = 7.5
CH = 220
CYA = ~120

Obviously, my TA and CYA are high but I thought it might be considerably higher. A couple of weeks ago I took a sample to the local pool store, and they said CYA of 90, but they weren't concerned about either it or the high TA, which they said was 120. Go figure, their fancy, dancy computerized strip reader isn't very accurate, that's for sure.

A month ago my CH was about 320, but with the addition of several thousand gallons of soft water, it's come down quite a bit, though I don't know if I should go much lower based on what I've read.

I used soft water because the well water is very hard at 35 grains, or ~612 PPM hardness, with 5 PPM of Iron, which is the real kicker. The pool has some iron stains, because the PO said he opened with well water this spring as he didn't want to pay the cost of using softened water.

For now, I dumped 3.5 gallons of 12% CL into the pool, which should raise it close to the 13.6 target for FC, plus 2 quarts of sequestrant to see if that helps with the iron stains. I haven't been using the trichlor tablets for about 3 weeks, and have added CL several times, but not this much. It appears that I have some algae causing the CC, but didn't want to add enough CL to get to the shock level needed at CYA of 120. Given that the CL has been around 3 or 4 for the past month, I guess I'm not doing too bad if I didn't get more algae than that. The water is also very warm, at about 92 F due to the cover I suppose.

I know that eventually I need to replace around 2/3 of the water in the pool, but I don't know that I want or should use all softened water to fill it again. On the other hand, I don't want to use straight well water either, due to the high iron. I also want to borate the pool, but figured I need to get the CYA and TA fixed first, or I'm just wasting a lot of Borax.

So I have a couple of questions.

Will a considerably lower CH cause problems with a fiberglass pool? If I replace about 12k gallons of water with softened water, I would expect CH to drop down around 100 or so. Will this cause any issues? Or do I need to add something to bring it back up again to avoid easy staining?

I also read that one of the best ways to deal with the existing rust stains is to use Ascorbic acid after the water is below 65 degrees and allowing the FC to drop to zero, so that's something for this fall, say Oct, I assume before closing it.

What would the experts recommend for this pool? There is only about a month or so left of this swim season here in northern Indiana, so my thoughts are too keep it going now, and then deal with the other issues this fall. Given that I technically should replace about 2/3 of my water, I suppose I could actually save quite a bit of refill water if I kept them separate using a large tarp like someone else did that bought a foreclosed property where the pool was a swamp. If I drain and refill at the same time, there will be constant mixing, and a lot more refill water will be needed to replace a given quantity of the water.

Will doing this also lower my TA down to where it should be? What is the ideal TA level? The well water is very close to neutral at 7.0, but the PO used lots of PH Up to keep his PH up, hence the high TA levels.

I want to go straight BBB with borates, as that should help a lot and make things much simpler. Now I'm spending too much time taking readings and trying to figure out the correct steps to take. Of course, part of that is educational, with a lot of time reading this website. Thanks, as it sure makes way more sense than listening to the "experts" at the pool store. Good grief, they have lots of different chemicals and Crud, and they aren't concerned about any of my readings. "Why, just dump in some other chemicals and that will take care of it"! They don't even seem to know that high CYA means that FC levels have to be very high too, and just recommend the normal 3 - 4 ppm of FC, and use an algae preventer. Yeah, and I can see that you will be constantly chasing your tail and more importantly, spending boat loads of money treating one thing or another.

Sorry, I know it's long and a lot of info, but I wanted to try to give the whole picture in one shot. Wish I could easily haul in 12k gallon of iron free water instead of waiting on the well pump. It takes forever to refill the pool with a garden hose, at about 1" per hour, and lot's of salt for the softener. Good thing I have a Kinetico dual tank system so you can use soft water out of one side while the other regenerates.

Thanks in advance

 

[JohnN]

Re: First time pool owner, measurements out of whack, now wh

First, retest the CYA using 50% tap water and 50% pool water, take the reading, and double it. That will give you a better idea of where your CYA is at. Also, when you did the TA test, did you wipe the tip of the bottle before each drop? Static can build up and make the drops smaller, and the reading higher. Do the test again wiping before each drop, and I bet your reading will be much lower. It is possible to maintain a pool with high CYA, but if you get any algae, it impossible to clear up. The best option would be to drain and refill, but I understand not wanting to cut into your already short swimming season.

 

[Charlie_R]

Re: First time pool owner, measurements out of whack, now wh

For lowering your CYA further (and cooling the pool a bit) you can start a siphon in the shallow end, with the hose about half the depth, and run your fill water to the bottom of your deep end. Keep the in flow the same as the out. Don't run the pump while this is working, to keep the water from mixing at this point. Run this for a few hours, then shut both off. Turn on your pump for a couple of hours to mix it all up. Repeat several times. Less stress on your softener.

You want to add borates to the pool, so check the advice in this thread: so-you-want-to-add-borates-to-your-pool-why-and-how-t4921.html

From what I've read here, you may want to keep your CH level close to or a little bit under what would be needed in a gunite pool.

The rest of your plan looks good, and shows that you have been doing your research. Thank you for that!

 

[kmdigital]

Re: First time pool owner, measurements out of whack, now wh

First, retest the CYA using 50% tap water and 50% pool water, take the reading, and double it. That will give you a better idea of where your CYA is at. Also, when you did the TA test, did you wipe the tip of the bottle before each drop? Static can build up and make the drops smaller, and the reading higher. Do the test again wiping before each drop, and I bet your reading will be much lower. It is possible to maintain a pool with high CYA, but if you get any algae, it impossible to clear up. The best option would be to drain and refill, but I understand not wanting to cut into your already short swimming season.

I will retest the CYA the next chance I get like you mentioned. And yes, I did wipe the tip of the bottle for each drop for the TA test, and the results were the same with the old K-2005 test kit.

I added three boxes of Borax over the last three weeks to raise the PH, as I figured that was better for controlling it than PH-Up, and would raise the TA less. It certainly wasn't enough to get it to 50 ppm, but the water feels better and sure is sparkly a day after you add it, but that has since dissipated.

 

[duraleigh]

Re: First time pool owner, measurements out of whack, now wh

Hi, km,

emphasizing what johnN said, redo that TA test if your kit is pretty new. Very fresh chemistry is affected by smaller drops and will skew that test high.

It's the only test that does that and it will go away.....I haven't pinned down exactly how much time it takes to get rid of that "charge" but I think a couple of weeks should do it.

 

[kmdigital]

Re: First time pool owner, measurements out of whack, now wh

Okay, checked things again today, as didn't have time yesterday and TA is still right at 190 - 200. I checked it with both the old and new kits, with PH = 7.5

Also retested the CYA, and it's 130. With 50% water dilution, it comes to 65 when I add enough in the tube where I can't even see a shadow of black dot anymore, so it makes it 130, so I was close before. I assume that's what you want, as it was at about 100(2) when it became hard to see, but I kept slowly adding until I couldn't make any shadow at all anymore.

FC is now 17.5 PPM and CC = 0, so I essentially shocked it by going fairly high over the weekend. Given the cover, I assume that the dissipation rate is low and it could take a while for it to drop substantially. What are safe swimming levels? Is it okay to swim with it this high?

Thanks in advance

 

[JohnN]

Re: First time pool owner, measurements out of whack, now wh

It is safe to swim when your FC is above the minimum for your CYA and below the shock level. With a CYA of 130, shock level is 30, and minimum is 10.

 

[CUTiger78]

Re: First time pool owner, measurements out of whack, now wh

If you've really only got a month left in your swim season, you might want to leave your drain/refill 'til next season. If you get into algae trouble this year, you'll need lots of Cl to fight it, so cal hypo might be your new best friend. It won't raise your CYA, it's easier to schlep around than gallons & gallons of bleach, and you can tolerate a bit more CH in your fibreglass pool.

If you do decide to drain & refill, if you siphon out a couple of inches, then refill each day, it might be easier on your well & water softener. It'll take a little longer, though.

Good luck!

 

[kmdigital]

Re: First time pool owner, measurements out of whack, now wh

If you've really only got a month left in your swim season, you might want to leave your drain/refill 'til next season. If you get into algae trouble this year, you'll need lots of Cl to fight it, so cal hypo might be your new best friend. It won't raise your CYA, it's easier to schlep around than gallons & gallons of bleach, and you can tolerate a bit more CH in your fibreglass pool.

If you do decide to drain & refill, if you siphon out a couple of inches, then refill each day, it might be easier on your well & water softener. It'll take a little longer, though.

Good luck!

Well, I bought the house, but won't live there till next year, and only go weekends now, so yeah, weather dependent, not more than another month or so as by Sep it will likely be too cold to feel like driving there to go swimming. Are you saying you would winterize with existing water, and not drain and refill till next spring if I decide to wait? Suppose that makes sense so don't have to rebalance everything before closing it.

Haven't had any algae problems so far, as obviously it doesn't get used very much.

Is there a generic name for cal hypo, as will likely need a bunch of that to raise the CH after refilling with soft water, unless I come up with a way to haul 10k hard but iron free water to dump in it.

 

[CUTiger78]

Re: First time pool owner, measurements out of whack, now wh

Are you saying you would winterize with existing water, and not drain and refill till next spring if I decide to wait? Suppose that makes sense so don't have to rebalance everything before closing it.

That's exactly what I'm saying. You'll probably drain some when you winterize, rain & snow will help refill over the winter, then see what you've got when you open. You might find your CYA at a manageable level and BBB & TFP will teach ya how to keep it there.

Cal hypo is generic slang for calcium hypochlorite. Many places sell shock which is cal hypo. Read the label to make sure. Cal hypo is a source of chlorine and calcium. It doesn't, however, add CYA.

Cheers!