View Full Version : PH 7.8 because I have to add water every other day
lagatella
08-13-2006, 08:49 AM
I have an ionizer. The pool has a slow leak which will be repaired this winter (will require digging up filter line). I have to add about an inch of water every other day and our tap water is about 7.8 PH.
That means I have to add that horrible Muriatic Acid almost every night. Is there anything else I can use besides that acid? Some other kind of PH decreaser that isn't so toxic?
Everytime I see that cloud of gas I wonder what I've killed.
Also have yet to add bleach since the PH is so high in about 3 weeks. Pool is clear.
P.S. The pool is 36,000 gallons
duraleigh
08-13-2006, 12:16 PM
Hmmm, where to start?
Everytime I see that cloud of gas I wonder what I've killed.
I'm not sure how you're applying it but I don't think I understand how you're getting a cloud of gas and killing something.
However, if you monitor pH carefully and dont like muriatic, run your pool at 7.8.
No chlorine in three weeks? That's gonna' be a problem. I doubt your pool is sanitized.
Post a set of test results and folks here will be glad to give you some advice on making your pool a little easier to manage.
lagatella
08-13-2006, 12:48 PM
All other readings are fine, just the PH is at 7.8, exactly what is coming out of the hose. Our pool person said he likes it to be at 7.4 which is what I was trying to get down to by using Muriatic Acid.
When I put the acid in (3 cups maybe at a time) by slowly pouring it into the deep end there is always a kind of cloud that forms and floats off. Even when I pout the stuff into a container you can see the vapors floating above it.
Was just wondering, since I am going to have to constantly play with the PH until we can get the leak fixed, if there is something not quite so toxic.
Our pool person said no bleach until the PH comes down, it was heavily shocked about a month ago before we switched to the ionizer. No chlorine reading now.
Poconos
08-13-2006, 03:15 PM
If I remember my chemistry the gas you're seeing is water vapor in the air hitting the surface of the acid and fuming. Muriatic is hydrochloric acid at a high concentration. Any time you add water to acid the reaction gives of heat and in the case of a high acid concentration adding water could cause the solution to boil violently so you never do that. Always add acid to a large quantity of water as you are doing. as Dave said, just run at a ph of 7.8. All other reading being 'fine' says nothing. Get a decent test kit if you don't have one and post some actual numbers. Your pool guy is wrong to say not to add chlorine until the ph drops. You need to do it ASAP. Again, to give more accurate advice we need actual numbers.
FC or TC -- Free or total chlorine
ph
TA -- total alkalinity
CH -- calcium hardness
CYA -- cyanuric acid
While you're at it, what type of pool?
Al
chem geek
08-13-2006, 03:55 PM
Was just wondering, since I am going to have to constantly play with the PH until we can get the leak fixed, if there is something not quite so toxic.
Our pool person said no bleach until the PH comes down, it was heavily shocked about a month ago before we switched to the ionizer. No chlorine reading now.
First of all, your pool person is dead wrong about not adding any chlorine to your pool, even with an ionizer. It is true that with an ionizer you can usually get by with a somewhat reduced chlorine level (similar to what salt water chlorine generator - SWCG - systems do), but you can't live without any chlorine at all. It takes a while for all the pool water to get through the ionizer to have all the pathogens and algae killed so you need chlorine in the water to kill locally introduced stuff (from bathers, bugs, wind-blown material, etc.) and to kill anything that is attached to your pool surfaces that will never go through your ionizer.
Also, your pool person apparently does not understand that although using liquid chlorine or bleach initially causes a rise in pH (liquid chlorine has a pH of 13 and bleach typically around 11), the normal consumption (using up) of chlorine is an acidic process that exactly compensates for this initial pH rise except that liquid chlorine has a small amount of extra base in it. Bottom line, using bleach does not increase your pH and using chlorinating liquid only does a little bit. A technical chemistry discussion of this may be found on this post (http://www.poolforum.com/pf2/showpost.php?p=27573&postcount=12).
In addition, the recommendation to just leave your pH at 7.8 is a good one. You do not have to fight to get your pH lower. Did your pool person say that the ionizer does not work at this higher pH? What reason does he/she have for why the lower pH is necessary?
Finally, though it is true that Muriatic Acid is not something you want to inhale directly (also true for liquid chlorine or bleach), you should be able to add it without causing problems. You can always wear gloves if you are worried about spilling any, wash your hands afterwards, and hold your breath while you pour. I know it sounds kind of weird to hold your breath, but I've gotten pretty used to doing that or, at worst, just hold the bottle and pouring far away from my face and "downwind" if there is a wind. The Muriatic Acid isn't "killing you", but if you inhale enough of it then it will cause irritation in your nose (mucous membranes) and eyes. Obviously, enough exposure to it would be serious, but you aren't going to put your face over it nor drink it so you should be OK. Unfortunately, other acidic alternatives, such as the dry acid Sodium Bisulfate, have their own problems of introducing sulfate into your pool and etching plaster (probably due to not dissolving immediately and sticking to the bottom or side of your pool surfaces).
Richard
lagatella
08-13-2006, 06:50 PM
It is a vinyl pool.
PH 7.8
TA 160
CYA 45
I've put the bleach in.
Your explanation of the vapor of Muriatic acid is exactly what I am seeing. I am very careful and do hold my breath like you said.
Thank you everyone for your help. Knowing I can keep the pool at 7.8 makes me worry much less.
chem geek
08-13-2006, 10:26 PM
Your TA of 160 is the primary reason that your pH is high (and why, after you add acid to lower it, it rises again) and why you are frequently having to add a lot of acid. Getting your TA lower to 100 (or even 80) will help a lot in reducing the upward pH drift and acid demand. Technically what is going on is that you are outgassing carbon dioxide from your pool because it is so far out of equilibrium with air (i.e. the carbonate alkalinity is too high).
Follow the procedure at this thread (http://www.poolforum.com/pf2/showthread.php?t=191) to lower your alkalinity and you will be much happier as a result.
Richard