Hi. I'm new to the forum and have appreciated all of the helpful advice and tips. I need to lower my TA and am going to try the aeration method I've read on this forum. Does anyone know how long you need to aerate to raise the PH? I have a 23,000 gallon plaster pool.

John,

It depends on how much aeration you can create. More bubbles=faster process.

Impossible to predict....it's a pool by pool basis.

Remember to lower pH first.

Thanks. I'll keep trying. So far I've blown air into the pool using a shop vac for 2hrs and the P hasn't gone up at all.

I turn the jets on in my spa and that creates lots of bubbles. If you have a spa don't forget to do that.

For about $40, my local Home Depot has a floating fountain by Poolmaster. It connects to one of your return lines. Looks good and aerates your pool while the pump is running. Don't want to burn up the ol' shop vac.

Great idea! It's shown here.

I lowered my TA from 180 to 90 this week, just using a 1.5 HP well pump and a PVC manifold that has 3 threaded outlets for hooking up water hoses. I just left the hoses off and let the water shower back into the pool, while the intake side was rigged to suck water from near the bottom of the pool. Crude, but effective. It took 3 days and I had to keep adding acid to bring the ph back down to around 7. I only let the pump run overnight once. My wife was bothered by the noise so I just ran it during the day the last 2 days.

The ph would rise pretty quickly the first couple of days, with little change in the TA. I would use the pool calculator to determine how much acid to add to drop the ph to 7 and then let the pump aerate all day. By then end of day 3 the ph was back up to 7.4 and the TA had dropped to 90.

Yesterday I did this process. I lowered the pH to 6.8, and then ran the the spa (therapy jets). To go from pH 6.8 to 7.3 took 10 hours.

I built a sprayer from PVC with an adapter for half inch pipe. Put a cap on the pipe, used a 45 degree elbow for directional purposes, drilled three small holes in the cap then screwed the whole thing to one of the returns. Makes a fairly nice fountain too!

I use what they call a jet air fitting. Works great with or without the solar cover on.

http://www.poolsupplies.com/cgi-bin/Com ... add=action





It replaces the eye ball in the return.

This sticky might be useful.

The sticky waterbear posted above outlines the procedure for lowering TA, but I want to throw in my recent personal experience.

The likelihood is that you will not see any progress in two hours. The amount of time it takes to lower your TA is a function of many different variables:

1. The size/volume of your pool
2. How effective your aeration method is
3. How consistently you are lowering the PH in response to rises in PH as the TA comes down

I have been fighting a very high TA in my 24' AG (approx 13,500 gal) for the past few days. Last Wednesday (5 days ago), I took my initial reading of TA at 300ppm. I have been aerating by pointing my return eyeball up to cause a strong ripple effect on the surface of the water. The pump has been running 24/7 since then, and as of this morning I have a TA of 180ppm. During this entire process, I have been checkin my PH twice per day. Each time I checked it, the reading was over 8 (which is a sign that the aeration is working). After each test, I would use the pool calculator to calculate how much acid I needed to add to lower PH to 7.0, and add acid accordingly.

So in 5 days, I've managed to lower my TA from 300 to 180, and in the process consumed just over 2 gallons of muriatic acid. The most important thing I can recommend is to keep retesting your PH at least every 12 hours during aeration process. The more often you recorrect your PH down to 7.0, the faster the process will be. If you have to keep adding acid to keep the PH down, you know its working. Don’t expect to see instant results; it’s a long and tedious process.

I just recently brought mine from 180 down to 60. My observations.

1. My ph would go from 7.0 to 7.2 really fast, then would slow down from 7.2 onward. I started checking my PH every 3-4 hours and when it hit 7.2 I would add enough acid to get it back to 7.0. This significantly sped things up for me, not sure if there is any science to back it up.

2. Aeration for the first portion, about 48 hours, I ran my pump so that the waterfall was running and the slide was running. This worked OK, but when I figured out that I should turn on my spa jets, that was like a turbo boost. I definitely saw a vast improvement after turning on the spa jets.

My total outlay of acid was ~4 gallons I believe. It matched chem geeks pool equations spreadsheet pretty closely.

I did get it down to 60 for a week, it is now back up to 80. I have a mystery pool that has a continually increasing TA, but that is another story. . .

The science behind it is shown in this chart where you can see that a lower pH makes a HUGE difference in the rate of outgassing. The effect of pH and also TA on the outgassing rate may be even more than shown on the chart due to some effects I've just been reading about in a book of pool water chemistry articles I recently received. At some point, I'll incorporate some of the concepts into my spreadsheet and update the chart and post the results in the Advanced Chemistry section.

Richard

Thanks to all who have posted for the great ideas and comments. This airjet fitting may do the trick. I don't have a spa or jets that can be turned up to aerate the pool. But, I do have a Polaris water fountain that I hook up to my pool cleaner return. However, I have been using that on a limited basis during the day because it's still relatively cold here in PA and I want to keep the solar cover on the pool to retain the water temp.

Thanks again

Good I wasn't imagining things then.

Maybe I'm missing something, but why bother lower your TA? Mine is 130 and my PH is stuck right between 7.2 and 7.4 without adding acid. Then again, I have a very old plaster job.

High TA levels combined with aeration will tend to raise the PH. Perhaps you don't have much aeration.

I have a high CH that I manage by keeping a low TA. A lower TA also lower my acid demand.

I have been working on the same situation for 8 days now. I started at pH 7.6-7.8 and TA 210. This AM I had pH 7.0 and TA 110. I have had my pool uncovered approx 15 hours per day with the return jets (3) pointing up and the spa blower or jet pump on. As soon as the pH is 7.2 I add another gal. of muratic acid (10 gal. and counting).

Shouldn't there be a jug of TA down that would make this process much faster?