So I tested my water today and my pH was 7.8 and TA 150. I read that you were supposed to add muriatic acid and aerate the pool to drop the pH and TA levels. My question is that will the TA level return back to 150 after I drop it down to around 90? Also, my tap water's pH is about 7.8 so does that mean every time I refill the volume of water that has been evaporated that I will have to use muriatic acid? Additionally, how do you aerate a pool? My pool is a fiberglass pool by the way.
Really high pH and total alkalinity
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Welcome to TFP!
Niether of those numbers is all that high. PH at 7.8 is the high end of the normal range. You will need to lower PH soon, but it isn't a problem where it is. TA at 150 is a bit high, but that isn't a big deal unless you have a SWG, fountain, spa, waterfall, or other water feature.
I recommend you lower PH to 7.2 each time it gets to 7.8, at least until the TA comes down.
The effect of adding tap water to the pool mostly depends on the TA of the tap water, not the PH. Which ever water has the higher TA will tend to determine the final PH. If the tap water is low TA, it will have almost no effect. But if the tap water is high TA it will be an ongoing issue.
There are lots of ways to aerate. Point a return up so it breaks the surface, install a fountain, kids splashing, air compressor, and so on.
Niether of those numbers is all that high. PH at 7.8 is the high end of the normal range. You will need to lower PH soon, but it isn't a problem where it is. TA at 150 is a bit high, but that isn't a big deal unless you have a SWG, fountain, spa, waterfall, or other water feature.
I recommend you lower PH to 7.2 each time it gets to 7.8, at least until the TA comes down.
The effect of adding tap water to the pool mostly depends on the TA of the tap water, not the PH. Which ever water has the higher TA will tend to determine the final PH. If the tap water is low TA, it will have almost no effect. But if the tap water is high TA it will be an ongoing issue.
There are lots of ways to aerate. Point a return up so it breaks the surface, install a fountain, kids splashing, air compressor, and so on.
Tap water gave a TA level of 150. So does that mean I'm fine or will I have to add a small amount of muriatic acid every time I refill my pool?
How much water are you putting in every time you top it off? My bet is that the "refill amount" is a relatively low percentage of total water volume, so the TA change won't be that big of a deal.hey said:
Probably every week or so 2 inches evaporate, but I'm not quite sure what the volume of the evaporated water is as my pool is awkwardly shaped. Given that the TA of my tap water is 150, will the tap water increase my pool's TA over time or stay the same?
Shape of my pool: http://oi50.tinypic.com/fwsopt.jpg
Shape of my pool: http://oi50.tinypic.com/fwsopt.jpg
With fill water TA fairly high, the TA in the pool will go up over time. Water evaporates, but the chemicals that cause TA stay in the pool. Then when you top off you are raising TA. You will need to compensate for that by adding acid regularly. Lowering the PH to 7.2 each time it gets to 7.8 will probably be sufficient.
The strength of dry acid and muriatic acid won't degrade over time like liquid chlorine will it? Also, how come when dealing with pools its called muriatic acid instead of hydrochloric acid?
I've got pretty close to the same fill water. Get used to adding acid. It doesn't lose strength like bleach, but you'll use it fast enough to not have to worry anyway.
Each time you lower pH with acid, TA will go down a little. Each time you add water, pH and TA will go up a little. I got aggressive with my water and did the acid/aerate thing to get TA way down. pH holds around 7.4 for several days at a time. I've learned from experience that each inch of water I add needs about a cup of acid. So if I'm filling, I just dump it in and let the hose stream disperse it. I usually increase the flow through the spa when I am filling, it aerates great.
Once you get regular about testing and dosing you'll learn your pool's personality.
Each time you lower pH with acid, TA will go down a little. Each time you add water, pH and TA will go up a little. I got aggressive with my water and did the acid/aerate thing to get TA way down. pH holds around 7.4 for several days at a time. I've learned from experience that each inch of water I add needs about a cup of acid. So if I'm filling, I just dump it in and let the hose stream disperse it. I usually increase the flow through the spa when I am filling, it aerates great.
Once you get regular about testing and dosing you'll learn your pool's personality.
Thank you guys, this has been a very informative thread for me. I'm going to try and see if adding trichlor tablets after every time I backwash will keep the pH and TA levels appropriate.
JasonLion said:
This, http://img220.imageshack.us/img220/7475/dsc0402x.jpg, is aeration which increases pH right?
Welcome to tfp, hey 
What is your current cya level?
Careful with that trichlor, it is adding cya to your pool. Cya is easy add but drain/refill to remove.hey said:
What is your current cya level?
Oh mostly I've been using liquid chlorine, but after several back-washes my CYA was depleted from 40 to 20 or less. So since I needed to lower my pH and add some CYA, I figured trichlor would work well in the situation.
Yes, trichlor will raise cya and lower ph, but you don't go from 40 to 20 doing backwashing. How are you testing?
Really? Back-washed like maybe 5 times for it to drop to 20. Using the CYA test from the Taylor k-2006, maybe I didn't shake the mixture well enough?
If you figure you can lower CYA by half, if you drain half your pool...
Yeah, 5 backwashes would not lower it that far. Unless you backwashed half your pool in those 5. ???
It's not how well you shake it, it's how long you shake. (seriously, your shaker's gotta be wonked if the mixture isn't shaken well enough, lol.). Personally, I find 60 seconds to be a much better wait/shake time for CYA. Actually I shake for 30-40, and let it rest for another 20. Then test. Multiple times (pour and re-pour).
I like the idea of trichlor lowering pH if that's what's needed. I just don't like the side effects of it. It stinks (pool smells funny), and makes black rings on my blue parts. Yuk. It's also unpredictable. I do like how it gets holes in it though as it dissolves. That's cool.
Yeah, 5 backwashes would not lower it that far. Unless you backwashed half your pool in those 5. ???
It's not how well you shake it, it's how long you shake. (seriously, your shaker's gotta be wonked if the mixture isn't shaken well enough, lol.). Personally, I find 60 seconds to be a much better wait/shake time for CYA. Actually I shake for 30-40, and let it rest for another 20. Then test. Multiple times (pour and re-pour).
I like the idea of trichlor lowering pH if that's what's needed. I just don't like the side effects of it. It stinks (pool smells funny), and makes black rings on my blue parts. Yuk. It's also unpredictable. I do like how it gets holes in it though as it dissolves. That's cool.
Frog is right, if you were to drain 1/10th of your pool 5 times (leaving time between to mix), then you would go from 40 ppm to ~25 ppm cya. On my pool (11000 gallons), that 1/10 volume backwash would be 5 inches of water, would take 22 minutes and 1100 gallonsfrogabog said:
That would be quite a backwash...my typical is more like 2 minutes and 100 gallons.Make sure you testing with your back to the sun (the sun should be out) and the vial at waist height. Here are the extended kit directions: http://www.troublefreepool.com/extended-test-kit-directions-t25081.html#p206397hey said:
Yeah sorry the min was actually 30 or less not 20 my bad. I also retested as per the extended directions and still couldn't get a reading. So I added 20 ppm CYA.
How exactly would you measure muriatic acid, is a plastic measuring cup fine or will it melt the plastic?