New Member, New Pool Owner, New Problems! High acid demand

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badshifter

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Jan 14, 2010
15
Hello All,
I'm John, from Southern California. I had a salt-water pool built last year, finished and filled mid October. It's dark gray plaster, free form shape, rock coping, jumping/sitting boulders at the edge of deep end, attached/raised jacuzzi with spillway. All Pentair Equipment, multi-speed main pump, seperate jacuzzi pump, heater, 60 gallon filter, chlorinator, auto-fill, multi-color LED lights, easy touch 8 panel with remote and a Hayward Ultra Vac sweep. It's about 16,000 gallons, approx 15x35 and 6 feet deep at deep end and big shallow end. My builder was awesome and we love the pool and use the spa 4-5 times a week. Only used the pool once or twice, waiting for warmer weather.

So, here is my problem and what brought me to this site. My pool needs acid almost daily. Not so much for pH which is running consistently high, but for alakalinty which is really high. I have to add at least 1 pound of dry acid daily to stay in this range. My local pool store has been helping but they basically say that salt pools do require a lot of acid. I haved tried liquid acid (lots of it and some results), dry acid (almost has no effect)but I have the best luck with a product called Easy Acid which comes in 1 pound bags. I have noticed a bit of scaling which I'm told is because of the high alkalinty.

My current numbers are:
Salt 3250 (very steady)
Chlorine 2.0 (Very Steady) with generator set at 15%
pH 7.8 and up (off the scale if I don't add acid daily)
alkalinity 220-250 (much higher if I don't add acid every day)
The pool shop checked my CA which was good and in range but I don't remember that number.
Equipment runs daily 8 hours.

The filter was cleaned shortly after start-up and again a week ago and looked normal. It's had stabilizer added, I've been told thats just the way it is with salt pools, that new pools have a high acid demand that lessen with time, I have bad luck and other less helpful advice.

I searched the forums and posts here and have found that I am not the only one to experience this but am not totally sure what the long term cure or maintainance should be. I don't want to damage the pool in the mean time. Is there any other way to lower the alkalinty and keep it in check?

The pool stays very clean, landscaping is not in yet so no trees, pollen, dirt, water runoff etc.

So, hello and HELP! Any ideas?

Thanks all,
John
 
Welcome! Hope you find our forum useful.

Some of the advice you have already received matches what we see and say on this forum as well.
- New plaster causes the pH to rise, for as much as the first year. You just have to stay on top of it.
- A SWG can cause the pH to rise, even without the plaster effect.
- A high TA will typically cause the pH to rise, even without plaster or SWG, especially if you have any water features (spouts, waterfalls, jets) that aerate the water.

You, sadly, have all three of these factors in combination (new plaster, SWG, high TA). So you have lots of sources of upward pressure on your pH.

Because you reported some scaling, that means you REALLY need to work on keeping the pH down. That's the most effective thing you can do to avoid scaling. It will also help reduce your TA.

Because you need to add lots of acid, I would recommend going back to muriatic acid, especially if you can find it at a reasonable strength (I have 31.45% locally). Some stores carry stuff that is only about half that strength, ~15%, so you have to use twice as much--but it doesn't fume, so some people like it better. Anyway, the reason I recommend this is that muriatic is hydrochloric acid, i.e. it's basically water, hydrogen, and chlorine; it doesn't put anything into the pool that isn't already in there. Dry acid or Easy Acid will add sulfates, which isn't necessarily bad but isn't necessarily good either.

You can also post a pic of your pool, which will induce oohs and ahhs and probably some pool envy. :-D
--paulr
 
Welcome to the forum!

Adding to Paul's good advice (and very good analysis of what's happening in your pool), I would suggest lowering your TA down around 70-80 by using the acid/aeration method found up in pool school.

Start by dropping your pH down to around 7.0....that's very important for the procedure to work.

Read through the article in Pool School and then post back with questions. It's not the easiest procedure and will not entirely eliminate your pH rise but I believe it will make it very tolerable.
 
Hello all again!
Thanks for the welcome and support. I will refine my numbers and post them but it seems like I need to get used to the acid drill for a while. I will look into an injector, home-made or commercial. I guess a more sophisticated test kit is in my near future as the cheapie blue box kit does not tell the whole story. I'll post a pic of the pool as it sits right now, but remember no landscaping or decorations yet! In the next month or so the trees, plants, ground cover, pool house and deck patio go in. Then the fun stuff begins. A vintage water tower, a mini roller coaster/mining cart, lights, gas lamps, and tons of neat (to me anyhow) old signs, gears wheels, stuff. Think Disneyland, Big Thunder Mountain Railroad look. It will make sense in a few months so bear with the unconventional description. My old house had a old west ghost town look, with buildings, a functioning gold mine car and tracks and all this in a normal sized backyard in a normal neighborhood but no pool, just a spa. OK, off to add acid.
Thanks again,
John

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Heres an update from last week. Made my own crude, but effective automatic acid injector and have been really monitoring the results. Here it is as of today:
Free Chlorine 6
pH 7.6
Total Alkalinity 120
CA 25
Salt 3200
So I'm getting closer and will just continue to monitor and add as needed. One last question, after cleaning the filter last week I get more water flow. Would the increase in chlorine number be because of the increased flow through the generator?

Thanks for the tips again all.

John
 
badshifter said:
Heres an update from last week. Made my own crude, but effective automatic acid injector and have been really monitoring the results. Here it is as of today:
Free Chlorine 6
pH 7.6
Total Alkalinity 120
CA 25
Salt 3200
So I'm getting closer and will just continue to monitor and add as needed. One last question, after cleaning the filter last week I get more water flow. Would the increase in chlorine number be because of the increased flow through the generator?
Click to expand...
You have the IC-40 SWCG generator? I think the important factors are pump/filter time, water temperature and the % setting on the generator. Warmer water, more time operating and a higher percentage setting should produce more chlorine.

Is CA = Calcium or Cyanuric Acid? Calcium Hardness contributes to the health of your pool as does Alkalinity. I see you've been able to reduce TA since the last post... Congrats!

It's good to have a fair amount of CYA (conditioner, stabilizer) in the pool so that the chlorine consumption is not accelerated by the sunlight.
 
Hi again,
Yes I meant CYA 25, low from what I'm told. I plan to add more conditioner. My pool store recomends 30-50 on CYA. The generator is an IC40 running @ 15% 8 hour run time. They didn't write numbers down for the Calcium Hardness, I'll be sure to ask next time.
John
 
Just to reiterate what FPM said, even the manual for your IC-40 recommends a stabilizer (CYA) level between 75-100 ppm. Always be a little skeptical of what the pool store tells you especially with levels and test results.
 
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