Another Newbie - Getting the Pool Water Balanced

[jhk49]

First off, this appears to be an excellent site. At first blush, this site seems to have a lot more answers than I have gotten in the past. At the pool chemical store I get the "deer in headlights" look when I ask a question.

I hope I can provide all the information you need on this first email so as I can get this pool under control.

I have a 25000 gallon in-ground pool with a vinyl liner and a sand filter. The pool is about 6 years old and when I have to add water, it comes from a well. There are a few trees around the pool as well as flower beds. I need the tress to provide not only the beauty but also the shade down here in south Georgia.

I have had a problem in the past with Algae as well as being able to maintain the proper pH and chlorine levels. I am not sure why but the chlorine level can't be maintained for more than about 4 days ... even after shocking it and keeping the pucks at a good level. The pH just never seems to be high enough .... I consider 7.2 - 7.4 as pretty good, but I can't seem to keep it in range.

I purchased a test kit and the following are my results:

pH = 7.0
FC = 6.0 ppm
CC = 0.8 ppm
Alk = 120 ppm
CY = 110 ppm

I have always used whatever the pool store sold me and to be honest, I am a bit timid on adding "grocery store" chemicals. However, like I said, I am more than willing to do it because I have to get this pool right.

If this doesn't work, I am considering a salt system to maintain the chlorine ..... but it is a bit expensive at $2500 to purchase/install.

Thanks for any help that you can give me.

JHK49

[PoolDoc]

If "CY" = CYA or cyanuric acid, your chlorine levels aren't nearly high enough. Read the "Best Guess" page linked in my signature. Also, it shouldn't take $2500 for an SWCG -- you can purchase a complete Pentair IC60 + powersupply at a1poolparts.com for under $1,000. I'm not necessarily recommending them, but I've gotten 5 units from them in the past 60 days. However, I wouldn't go that route, till you've resolved your pool problems. A SWCG is just a *method* of adding chlorine.

Do this:
#1 - Add 4 gallons of plain 6% household bleach as soon as you can (~10 ppm)
#2 - Purchase a cheap OTO/phenol red drops testkit locally. Usually, you can get one at Wal or K-mart.
#3 - Read the Best Guess page.
#4 - Order a Taylor K2006 or 2006C testkit. You can use the Amazon link in my sig. When the seller is "Amato Industries" the price is as low as I've seen, and they consistently ship the correct kit (others sometimes sub the cheaper K2005).
#5 - Till the K2006 kit arrives, use bleach to keep your pool in the DARK yellow to light orange range on OTO (10 - 20 ppm)
#6 - Brush your pool and run your pump 24/7
#7 - Post back once you have the Taylor results OR if you have some sort of problem.

The chlorine 'demand' (usage) you are experience can be several things, ranging from beginning algal growth, to various additives such as cheap algaecides or other 'booster' products. With your stabilizer that high, high chlorine levels are required to kill things, and keep your pool from becoming a mess. You can swim safely and comfortably at those levels, but don't wear new expensive swim suits.

[CarlD]

If it isn't obvious, those pucks are the source of two of your problems: Your low pH and your high CYA!
Yup. Pucks are super-acid and drive pH down.
Also, for ever 10ppm of chlorine they release, they add 6ppm of CYA.

Consider a partial drain and refill to get your CYA under control. If it's TRULY 110, then replacing half your water will give you a CYA of 50-60...good for the hottest part of the summer. I like to raise CYA from 30 to 50 sometime in July. But, living in NJ, I don't like going over 50. Our moderator in Louisiana, Janet (aylad) runs CYA at 80 because even though her maintenance level of FC is high, she doesn't have to add it often. Much sunnier and hotter more often down there.

Pool stores don't tell you this stuff then they say "Oh, boy: You have 'Chlorine Lock'!" There is no such thing, just alternate levels of free chlorine to maintain.

Carl

[jhk49]

Thanks for the feedback ..... this is what I know now:

I already have a K-2006 test kit and I took a second reading this morning. The results are:
pH - less than 7.0 (the color scale doesn't go lower)
FC - 0.5 ppm
CC - 1.0 ppm
ALK - 100 ppm
CYA - greater than 110 ppm (again the scale doesn't go higher)

So, what I have done this morning is to drain approximately half of the pool (12,500 gallons) and I am presently in the process of refilling to the proper level with well water (this should be completed by 6:00 pm). I then plan to sufficiently blend the two water types overnight and then take another test.

I plan on going to the local grocery store to purchase chlorine and borax if need be. Do you have any suggestions on how much my initial purchase of bleach and borax should be?

Of course, any other suggestions that you might have would be most appreciated.

jhk49

[PoolDoc]

I'd get 4 boxes of borax and 12 gallons of bleach. Add no more than 1 gallon of bleach tonight -- since I don't know if your well water has metal (iron?) in it. Do NOT raise your pH yet. Do run your filter 24/7. Do test your water once the pool is full.

Also, if you can get it, add some polyquat (see this page: www.poolsolutions.com/gd/polyquat.html ) but do NOT buy the HTH brand. HTH and Walmart have gone over to the dark side. Walmart's pool chemicals are awful, and HTH has kept the brand name but changed the contents to to 'goop'. You'll probably need to go to a pool store, and you MUST use the chemical name to check what you are buying.

The problem is, you need high chlorine to kill algae, and you need low chlorine to keep metals in your pool water from staining your pool!

[jhk49]

Here is the newest skinny ........ I had already added 1.42 gallons of bleach last night before I got your email.

After blending/filtering all night ..... here are my test results:

pH - less than 7.0, base demand = 20 drops
FC - 1.5 ppm
CC - 0.5 ppm
Alk - 110 ppm
CYA - 80 ppm

I don't think that I have a "metal" problem to any degree with my well water ..... I never see much (if any) staining either around the pool or inside the house (bathrooms, washer, dishwasher, etc).

Using the guide in the Taylor test kit and calculating based on 6% chlorine with a 25000 gallon pool, I come up with adding just 54.4 ounces of bleach (I'll use a 1/2 gallon) to get in the proper FC range

Then, also using the Taylor guide, I nned to add 16 pounds of soda ash to increase my pH to the proper range. I am figuring on only adding 12 pounds (I am a bit timid since I want to use the pool by Monday for the 4th).

Let me know what you think. I would like to hear your opinion but if you are tied up, I'll go ahead with the plan by late tonight (9:00 pm EST or so).

As to the poly ..... right now I am not showing any signs of algae but my history has not been good. Shall I go ahead and add a quart?

Again, thanks for your help to this newbie.

JHK49

[PoolDoc]

You'd be better off not trying to use such precise calculations: pools don't actually respond that exactly, and the decimal.ed numbers imply that they will. The Taylor guide book is, in my opinion, one of the worst things in the kit.

For a 25,000 gallon pool, with 80 ppm CYA and NO metals and NO visible algae, add 4 gallons of bleach -- NOT 1/2 gallon! (Read the Best Guess page, linked in my signature.) For a pH below 7.0, add 2 boxes of borax slowly via the skimmer (pump on) and retest after 2 hours. With your CYA that high, you can add the bleach any time -- it's not necessary to wait for this PM.

Your TA is already 110, so it would be better to avoid the soda ash, which increases both pH AND carbonate alkalinity and use the borax as needed instead.

[CarlD]

And, as pH rises, you will see your T/A rise, too. That's normal. We can address that later.

"Standards" for adding chemicals to pools seem to fall into two categories: When talking about chlorine, they always want you to add far LESS than you need. When talking about anything else, they always want you to add far MORE than you need. I usually use between 1/4 and 1/2 the "recommended" (on the package) amount of anything, because it's always easy to add more. With chlorine, and years and years around here, I usually pretty much know how much to use without the gradualist approach.

Carl

[jhk49]

Thank you much, I am making progress under your tutelage. Yesterday, I added 4.4 gallons of bleach as well as 2 boxes (approx 8 pounds) of borax. This morning my test results are as follows:

pH - 7.2, base demand at 12 drops to raise to 7.6
FC - 5.5 ppm
CC - 1.0 ppm

The FC level is right in range for the min/max level per the "best guess" chart with CYA's of 80 ppm. But, the pH appears to be a bit on the low side. The Taylor book, as you had mentioned isn't always accurate, indicates an add of 9.6 pounds sodium carbonate to bring the pH up to 7.6 ........ do you believe that an add of 1 box borax would be correct?

On another note, so if I take the time to maintain the levels of water chemistry within range on a daily basis, I should be able to have clear water without algae throughout the season with only minor exceptions?

jhk49

[PoolDoc]

Hi JHK;

I've been responsible for up to 24 large commercial pools (100,000+ gallons) in a season, and averaged 1/4 green pool per season out of 24. In other words, in 4 years, I had one pool out of 24 turn green 1x during a single swim season.

Does that answer your question?

Regarding the soda ash (sodium carbonate), use borax instead. But, unless you have a concrete pool, don't worry about trying to get the saturation index right, or the pH up to 7.6. Anywhere between 7.0 and 7.8 is fine.