Newby setup - Please advise

[durnik56]

Please help me set my pool for swimming. I got an Intex 16'x48" pool (5000 gal.) for the grandkids. Set it up and filled. Per your preliminary instructions I added 2 qts chlorine bleach and 1.5 lbs CYA. Using test strips, my readings this afternoon are:

CYA 10ppm
Total Alkalinity 0
PH 6.8
FC 5 ppm
TC 5 ppm
Total Hardness 50

I know I need to add Borax - how much do I need? What else do I need to do? Please help - the grandkids are anxiously awaiting the OK.

[AnnaK]

Welcome to the Pool Forum!

The 24 oz stabilizer you put in will give you 36 ppm of CYA once it's all dissolved and mixed in. They also would have dropped whatever the pH of your fill water was by 0.67 points. The 64 oz of bleach would bring the FC to ~ 5 ppm.

Your test strips won't read the CYA for a day or two and even then, they won't be exact. In the absence of a drop based test kit such as the HTH 6-Way from Walmart you can either have the water tested at a pool store or you can rely on the Pool Calculator.

The low pH reading makes sense given the amount of CYA you added. We'll need to raise that right away and increase alkalinity as well. I don't really believe the test strip result of 0 TA (alkalinity) unless you filled the pool with distilled water. Probably not though, huh?

I would:
1) Add 30 oz of baking soda to increase alkalinity; this will raise pH just a little as well. This amount is less than what's recommended by the Pool Calculator; I am making the assumption that there is some alkalinity in the water but is not being picked up by the test strips. We can always add more later. Help the pump mix this in by swishing your brush or the net through the water.
2) Add 22 oz of borax (20 Mule Team) or 10 oz of washing soda (not both). These will raise pH.

Don't let the grand-kids in until the pH is at least 7.2. The above additions should get you somewhere between 7.3 and 7.4. We can fine-tune the balances once you have the HTH test kit or results from the pool store.

A plastic 2 cup measuring cup is a good tool to have since most have calibration marks in ounces. A 4-cup one is even better if you can find it. If you decide to use the Pool Calculator you'll notice it gives amounts in "by weight" and "by volume". Use the "by volume" amounts if you're using a measuring cup.

If you're able to make those additions in the morning I bet the grand-kids will be in the pool after lunch. Have fun!

[CarlD]

I would disagree with Anna and say you need to get your pH up first. I personally would never add 2lbs of baking soda to a 5000 gallon pool all at once. I have a 20,000 gallon pool and I never add more than one pound at a time. Plus, T/A is your least concern right now.

I would add about 1/4 box of either Borax or Washing Soda (on that we agree) but do NOT add a full box of either yet. Start small, test, and add more. Otherwise you risk overshooting your target. I've seen people use the pool calculator for acid demand or base demand and overshoot too many times. Too many factors aren't compensated for. So it's better to use less, test, and add more. Otherwise you'll now have to add acid to bring it down.

Meanwhile, you need to get a better way to test pH. Strips are NOT accurate or reliable. Your pH may be quite a bit higher.

You'll need a proper test kit but in the meantime you can either get a simple OTO kit that tests chlorine and pH for about $7 or go to Walmart and get the HTH 5-way or 6-way drop test kit (little bottles) for about $15. It's a good alternative to the more expensive but ideal Taylor Technologies K-2006.

You can get the Taylor K-2006 from taylortechnologies dot com, amatoind dot com or there's a place on eBay (I think) that makes a donation go to Pool Forum (aylad or Watermom can tell you).

[AnnaK]

Hi Carl,

Please help me understand why we wouldn't want to address the TA just yet.

The addition of 1.5 pounds of CYA made the water in this pool into an acidic solution. We can raise the pH with borax but it won't stay up because it has no buffer to keep it up (TA=0). If we can raise the alkalinity of the water some then the pH change would be more lasting, wouldn't it?

[CarlD]

Anna,

First off, we don't know that the pH won't stay up--check out Chem_Geek's and Waterbear's work in the China Shop. We are looking at recommendations of MUCH lower T/A than before. Meanwhile, unless pH is oscillating, T/A in a vinyl pool isn't really relevant. I KNOW we always recommended T/A of 80-120, but pH is more important by far.

Second, I NEVER recommend adding the full amount of ANYTHING a calculation computes other than chlorine. 99 times out of 100 you over-shoot your goal. It's always better to add increments and test. It's far easier to raise T/A than to lower it. Better to be low and add a little more baking soda or washing soda.

Third: I use test strips everyday () primarily to tell me if my chlorine is holding or has fallen off--if I boosted my FC and it's dark purple I know FC is holding. I use the best--LaMotte 6 way or Hache Silver. The pH test on these things are WORTHLESS as is the CYA test. After years I can ALMOST get a good guess of the actual pH I currently have about 50ppm and the strips indicate I may not even have 10ppm.

So I'm not convinced the pH test is accurate. Until we know, I don't want to see durnik56 add massive amounts of anything and then have to compensate for THAT.

5000 gallons is a small pool which can be delightful, but it's also much more sensitive to dumping chemicals in by large amounts.

[AnnaK]

Thanks Carl.

I totally agree with you in that we should rarely add the full amount of a compound initially. That's why I said "we can always add more later" in my first post.

I'm learning as I go along and I appreciate your input. It had always been my understanding that you can't achieve a neutral pH in an acidic solution unless you add an alkaline buffer. I'm not necessarily basing my evaluation of this pool being acidic solely on the test strip pH but also on the calculations of the effect of adding 1.5 pounds of CYA to 5000 gallons of water. That alone would drop the pH by 0.6-something. Even if the fill water pH was at a neutral 7.5 it would go to 6.9—and that was kind of verified by the test strip pH.

I've been reading Richard's and Evan's posts; the China Shop is one of my favorite hangouts. Somehow I completely missed that TA isn't relevant in a vinyl pool. I knew we didn't need to be overly concerned with calcium but always thought we needed some alkalinity to buffer the water.

Live and learn. Thanks for setting me straight.

[aylad]

You can get the Taylor K-2006 from taylortechnologies dot com, amatoind dot com or there's a place on eBay (I think) that makes a donation go to Pool Forum (aylad or Watermom can tell you).

Here's the link to Amazon, that gives PF a donation when you buy from them... http://www.amazon.com/gp/product/ima...toys-and-games

You also can get it for a good price at http://www.spspools-spas.com/

Janet