Aerate to raise pH with compressor on return line

[slackerUH]

I am trying to come up with an easier solution to handle the poor source water we have at an older hotel with a small water park. The water park has two small pools and a hot tub.


16,000 gallon pool with water slide
12,000 gallon pool with play feature
1,000 gallon hot tub

The main problem is the source water has an alkalinity of 250. I would like to come up with the easiest way to get the pH and alkalinity balanced. We have had turnover with maintenance staff and it is difficult to get an already busy maintenance person to understand a complicated procedure to balance the pool.

I have read quite a bit about lowering the pH and alkalinity with acid and then aerating to raise the pH.

My idea is to have an air compressor connected to the return line somehow and then connect it to some sort of timer. For example, dump in the proper amount of acid to lower the pH to 7 and then start the timer on the compressor which will be blowing air into the return lines from inside the equipment room. After some trial and error, I will know how long the compressor needs to run to raise the pH. Then repeat this process until the alkalinity is at a more favorable level.

I have read some posts mentioning lowering the pH to 6 and then aerating but I would like to avoid lowering the pH too low because of potential damage to the heaters.

I'm not sure exactly where or how I should connect the air compressor to the return line or how to trigger it. I would assume at some point after the heater.

Any suggestions would be greatly appreciated.

 

[mknauss]

Welcome to the forum! :handshake:

I would be sure to put the air inlet after all filters, heaters, etc. Last thing before it goes to the pool. A fountain also works really well.

Please add a signature. Read Pool School - Read This BEFORE You Post
Information in your signature will show up each time you post and it makes advice more accurate as we know what equipment we are dealing with.

If you are interested in learning more about TFPC, I suggest you read Pool School - ABCs of Pool Water Chemistry and consider reviewing the entire Trouble Free Pool School book.

- - - Updated - - -

Also, do not lower pH below 7. It will damage your heat exchangers.

 

[duraleigh]

Welcome to the forum

You certainly have grasped the process very well.

I am not sure you gain much by introducing air in the return line as opposed to submerging a hose in the pool water body. If you decide to do it in the return line, I agree with mknauss, it should be last in the sequence.

 

[Richard320]

How do you propose keeping the 90 psi in the compressor from overcoming the 20 psi in the filter and backwashing the filter through the pump and back out the skimmers? If you put a check valve before the air inlet, you will get no water circulation as long as the air pressure is greater than the pump pressure. So if you do get any flow, it will be under tremendous pressure and you won't get any bubbles anyway -- you'll get filtered water shoved into the air tank.

If you want to aerate seriously, use the search box for aerators. Here's one to get you started. Scroll through and look at the pictures Best Method to Aerate

 

[duraleigh]

The 90 psi in the compressor is quickly released out the returns and cannot be maintained in the return pipe as long as it has an outlet into the pool.

 

[slackerUH]

Thanks for your response and I want to add some real world example to your update. Our hot tub at the property I am referencing in this post just had a heat exchanger last 3 months before it was destroyed by assumed bad chemistry. New maintenance person and outdated chemical controllers which I am pretty sure led to very low pH and ruined the copper heat exchanger. I am set on using closed loop boilers with titanium heatswapper exchangers to prevent chemical damage from inexperienced maintenance staff.

Also, I will need to read into the rules and signature. I personally have a simple pool at my house in Hawaii with a Hayward Tristar 950 pump and Hayward 36 sqft DE filter but I help support the pools at several different small hotel properties in the midwest. I have been reading posts on tfp for years and this is just my first post.

 

[slackerUH]

The 90 psi in the compressor is quickly released out the returns and cannot be maintained in the return pipe as long as it has an outlet into the pool.

duraleigh I believe what you are saying here is what I was assuming. If the air compressor is connected at the last part in the plumbing before it returns to the pool, the path of least resistance would be for the air to go in the direction of water flow and out the jets. I would prefer not to make any external modifications like what Richard320 mentioned. We do have a water feature and a water slide in the two different bodies of water which I would assume could do the aeration process however, that requires a lifeguard or someone to be there the entire time they are running. My ideal setup would be to push a button or turn a dial for a set amount of time that triggers an air compressor in the pool equipment room.

My goal is to create a very easy process for maintenance staff to lower pH and alkalinity with acid and then raise pH with aeration to solve our high alkalinity problem at this one specific property.

I have asked multiple pool companies (but I think the smartest pool people are on this forum). Some think my idea is crazy and some think we should just have ecolab deal with the water.

 

[mknauss]

What is special about the fill water at the one property with the high TA? I would think high TA water in Hawaii would be difficult to have since you get large amounts of rain.

 

[slackerUH]

What is special about the fill water at the one property with the high TA? I would think high TA water in Hawaii would be difficult to have since you get large amounts of rain.

You are correct about the TA in Hawaii. I add Sodium Bicarb weekly in my home pool. The Location with high TA is in Brandon, South Dakota at a small indoor water park. When I asked my friend that has a Culligan store, he told me that he assumes the City of Brandon adds Lime to the water. Several people have told me the water quality is poor there.

 

[mknauss]

Color me confused. Your location says Hawaii and you are dealing with a pool in South Dakota ----- I would pick Hawaii!