Another Novice Needs Help, TA & CH Problems...

We have an in-ground heated, diamond brite, 27,000 gallon, SWG system pool with a spa and a large weeping wall and waterfall. Completion was back in Jaunuary. Pool builder did initial shock, and initial chemical servicing. I've had big problems with this company since, and have pretty much been on my own.

Okay. At first I took early readings on TA and CH, which were in normal range. I had some issues with a low CL level during the colder months and mistakenly raised the percentage of the SWG to 60%, where it stayed for awhile. I've since recently lowered it back down to 50%, with the spa at 10%.

After some recent storms, I decided to do a full chem check. My Total Alkalinity is now reading 50 ppm, with my pool Calcium Hardness at 430 ppm. I use a Leslies/Taylor test kit which recommends spa CH to be 150-250 ppm, and my spa reading was even higher at 465 ppm. That is alarming.

I've had issues with a climbing PH all along, which often shoots up over 8, but have heard I will get this with the SWG. I add about a gallon of Muriatic a week, which I also heard may be normal, and it immediately comes back down to 7.2 or so. CL level is now fine, now that the weather has heated up. And I can often smell the chlorine in the water.

My CYA level is about 50, which I've heard is normal for a non-SWG system but may be a little low for me. I brush and vacuum my pool regularly, and my water is very clear and beautiful.

I've taught myself enough about this where I think I can take my pool care to the next step, I just need some help now to get the training wheels off. What do I address first, and how do I go about doing it??? The calculator says add 16.49 lbs of sodium bicarbonate (baking soda?) to bring my TA up to 90, but I've heard Chem Geek say the best way to raise TA is only add two lbs at a time and retest.

Should I bring up my CYA level?

Right now I'm thinking my rising CH level is the biggest concern because as an aircraft mechanic I know corrosion is dangerous in any environment. I belatedly realize running my SWG at a higher level probably contributed to my problems, as some of the chlorine gas probably did not disolve in the water.

Lastly, I live in the DFW area where we've had some wicked weather. One day we had five inches of rain and I had to pump out water as it was at the top of my coping. We have also had at least to different hailstorms, one of which produced golf ball sized hail. I've heard hail can jack with your pool chemistry as well. Another factor may be my 2 HP two-speed filter fump filter clogged and I was without my main filter pump for about two days until I figured out that it needed cleaning.

I am absolutely grateful to have this forum, and would appreciate any and all help.

Regards,

Mike
Arlington, TX

CH is calcium hardness, and has nothing to do with your chlorine or SWCG settings. Being able to smell the chlorine can be a sign of problems. Can you test for Combined Chlorine? Not common with a SWCG, but often chlorine smell is an indication that you don't have enough chlorine and need to shock the pool. What is your chlorine level?

I don't understand why your spa has different readings from your pool. Are they completely separate plumbing systems?

CYA level should be at whatever the SWCG manufacturer recommends. Some are higher than others.

OK,
I think you are better off than you think.

Yeah, your calcium's a bit high, but not terribly. For your pool CH should be in the 200-400 range and you are hitting 430-465...The diff between the pool and the spa could be do to two obvious factors:
1) Simple measurement error. It's not an exact science and your variation is less than 10%.
2) This is a new hard-sided pool. It's still curing. It's very possilble that the spa, with a different quantity of water, at a different temp, is curing differently. Again, only a <10% difference--not to worry.

I would use the rains as an opportunity to drain off some of the hard water--rain is soft--to get CH below 400.

Meanwhile, T/A: The low T/A is making it a little tough to keep pH steady, but it's also preventing the CH from causing a BIG problem. Follow Chem_Geek's advice--my rule is ALWAYS add stuff slowly, wait, re-test, and add more. Given your slightly elevated CH, aim for T/A to be around 80 or 90--but that's when pH is between 7.3 and 7.6--T/A rises and falls with pH. If pH is higher, then a T/A of 80 is a bit low.

pH: You have TWO factors raising pH--the SWG, as you know, but also the new concrete/shotcrete/gunite/tile/plaster pool. These pools are NOTORIOUS for increasing pH as they cure...adding Muriatic acid to control it is the best thing.

CYA/Stabilizer: Normally 50ppm is the high end of what I like (there are technical reasons why higher levels can be preferable--Aylad runs at 80ppm because of them). But the SWG manufacturer will have a recommendation--usually higher. I'd like to see you stay at the very low edge of that. CYA is EASY to add, hard to get rid of. You can use a floater with Tri-chlor pucks--it will fight the rising pH as well as Tri-chlor is VERY acidic.

Or you can add CYA and let it dissolve. I ALWAYS recommend you compute how much CYA you need and add 1/4 to 1/3 of that--no more. Wait 48 hours to a week for it to fully dissolve and measure CYA. Repeat as needed.

Chlorine: You didn't post levels. "Normal" means little to us. You have Free Chlorine and Combined Chlorine/Chloramines. The former doesn't smell. The latter smells like "chlorine". It usually means you need to shock your pool. If otherwise it's just fine then simply shocking it once up to 15ppm (since your CYA is 50) should be all you need.


Still, I think you seem to be in good shape. I suggest you get a good FAS-DPD Chlorine test kit--but we suggest EVERYBODY get that, whatever the brand.

OK,

First, thanks for the replies. My free CL level seems to range between 3 to 5 ppm, mostly at 5. I test everytime for combined chlorine, and the Taylor kit says it is negligible. After adding the third set of drops I really can't see any difference. Also, we simply have not used the pool (once swimming in the pool, 4-5 times in the spa max.)

My pool and spa ARE plumbed together, that may have been a reading error on my part. After adding 40 drops on the second test I could've miscounted. Also your temp/curing theory is very likely too. I was concerned as the test kit said to look for a smaller ppm level. Maybe that only refers to a spa only system?

I will first slowly add two cups/lbs of baking soda at a time, with a target Total Alkalinity of 80ppm. I can handle keeping that PH level between 7.3-7.6. It is OK to add 1 gallon of Muriatic at a time right, or should I use the calculator to be more precise?

CYA- I used the powder once awhile back to bring it up from 30ppm after I'd heard the SWG preferred levels are higher. I put it in an old sock and floated it in the skimmer, leaving it in there about 5-7 days until it disolved. I understand the dangers of not letting the CYA get too high and have no desire to drain my pool. I'll recheck what Hayward recommends and shoot for the low end, 1/4 to 1/3 dose at a time.

I feel the chlorine smell is very faint, not overly strong. With our limited use so far, is it possible I need to shock? I've heard that combined chlorine mainly comes from sweat, suntan oils, bodily fluids etc. If so, should I use bleach or another brand liquid cholrine? I've already ruled out using the SWG.

Lastly, I've already had to add hose water twice since January to compensate for evaporation. It gets hot here in Texas quick. I'd hate to pump water out. Are you saying the best way to bring down the Calcium Hardness is to pump water out after hard rains? Right now my level is up about two to three inches from recent days rains.

Again, thanks to all. I'm getting the hang of this quick.


Mike
Arlington, TX

Mike,
Sound like you are on the right track, generally.

I've often noticed that my pool, even with high chlorine, doesn't smell, but if I get in and out, I then smell the chlorine...I presume it's the impurities on my skin...sweat, suntan lotion, whatever. That makes perfect sense as the CC's will be generated right around me.

Thanks Carl... I'll pump out a little water tonight and keep a close eye on that CH. Meanwhile I'll do a lunch trip to the commissary here on base for some baking soda, and add two cups at a time then re-check.

I'll SLIGHTLY boost my CYA and all the while keep a close grip on the PH. I certainly can get acid cheap enough at the BX.

This place rules...

A couple of 2 lb boxes of baking soda added to the pool, 6-7 inches of water pumped out and refilled by hose, a forty lb bag of salt added to account for the lost water, a cup or two of CYA stabilzer added to the skimmer via socks, a tight control on PH levels, and a pool with all readings within limits...

Priceless.

Alkalinity 90
CH 370
Salt Level 3000 ppm
PH 7.2- 7.6
CYA 60

Of course, this was all before the 4-6 inches of rain we got from monsoons over the last two days.