Preparing to start Ascorbic Acid treatment

[Katygreys]

Link to previous post where I used vitamin C to confirm iron staining, complete with before/after pics of spot treatment:

Previous Post

I plan to drain and refill. I have no desire to add sequestrant and fumble around with more chemicals. Leslie's super-accurate iron testing (sarc) says I have zero iron in fill water. More details in previous post. We have had a lot of rain in Katy lately, so plan to drain about 30% to get a head start (somewhat scared of pool popping out of ground), then do a no-drain-water exchange to get as close as possible to a 100% drain and fill. Questions:

• Do I need to remove my cartridge filters since I am not using sequestrant and will do a drain and refill?
• Current CYA is 50ppm. I plan on using CYA as a measure of how much water I have exchanged. As such, should I bump my CYA to 100? I am thinking this will give me a more accurate scale to determine percentage of water that has been exchanged. Example: Should be easier to determine via CYA test a reduction from 100 to 20 than a reduction from 50 to ~10...know what I mean?
• Since I am not using sequestrant and therefore am not concerned about high pH post-AA treatment causing iron staining, and considering that adding AA will lower my pH...where should I get my pH to before adding AA? Just stick with the 7.2 as recommended?

Thanks!

 

[ezchief]

Not an answer but I know when I converted to liquid chlorine 3 years ago with cya at 80, I calculated and did a 50% water change. At the end my cya was at 40. It made it easy for me to measure. Don't see why not in your case.

 

[ezchief]

When I started the drain, my sump was moving out 4 gallons per minute from one end of the pool. My fill was coming in at 5 gpm using a 5 gallon bucket and timing it. So I waited x minutes/ hours before turning on the fill water to the other end. My level dropped about an inch or two below the tile line before turning on fill water. Real easy to figure out.

 

[Bperry]

Link to previous post where I used vitamin C to confirm iron staining, complete with before/after pics of spot treatment:

Previous Post

I plan to drain and refill. I have no desire to add sequestrant and fumble around with more chemicals. Leslie's super-accurate iron testing (sarc) says I have zero iron in fill water. More details in previous post. We have had a lot of rain in Katy lately, so plan to drain about 30% to get a head start (somewhat scared of pool popping out of ground), then do a no-drain-water exchange to get as close as possible to a 100% drain and fill. Questions:

• Do I need to remove my cartridge filters since I am not using sequestrant and will do a drain and refill?
• Current CYA is 50ppm. I plan on using CYA as a measure of how much water I have exchanged. As such, should I bump my CYA to 100? I am thinking this will give me a more accurate scale to determine percentage of water that has been exchanged. Example: Should be easier to determine via CYA test a reduction from 100 to 20 than a reduction from 50 to ~10...know what I mean?
• Since I am not using sequestrant and therefore am not concerned about high pH post-AA treatment causing iron staining, and considering that adding AA will lower my pH...where should I get my pH to before adding AA? Just stick with the 7.2 as recommended?

Thanks!

The CYA test has a big error tolerance so don’t go adding CYA just to use it for that. The pH should always be in the 7’s unless the AA treatment specifically calls for something different.

 

[Katygreys]

Thanks @Bperry . If I may challenge a bit...so yes, CYA for sure has a not-too-insignificant error bar, as it's a rather subjective measurement. But, my ultimate aim is to get the iron into solution and the drain as much of the dissolved iron out of my pool as possible. If i was not afraid of popping the pool outta the ground, I'd just drain it 100% and fill it, end of story. But with the no drain water exchange, I'll have some uncertainty about how much "old water" (water with dissolved iron) I have actually removed form the pool. Whether I start from 50 CYA or 100 CYA, my intention would be to exchange water until the test water after adding the CYA test solution is crystal clear. So yes, maybe bringing up to 100 before the exchange it pointless...I was just thinking I'd be able to monitor the decline (and hence exchange percentage) "more accurately" on the way from 0% exchanged to 100% exchanged.

 

[Bperry]

Thanks @Bperry . If I may challenge a bit...so yes, CYA for sure has a not-too-insignificant error bar, as it's a rather subjective measurement. But, my ultimate aim is to get the iron into solution and the drain as much of the dissolved iron out of my pool as possible. If i was not afraid of popping the pool outta the ground, I'd just drain it 100% and fill it, end of story. But with the no drain water exchange, I'll have some uncertainty about how much "old water" (water with dissolved iron) I have actually removed form the pool. Whether I start from 50 CYA or 100 CYA, my intention would be to exchange water until the test water after adding the CYA test solution is crystal clear. So yes, maybe bringing up to 100 before the exchange it pointless...I was just thinking I'd be able to monitor the decline (and hence exchange percentage) "more accurately" on the way from 0% exchanged to 100% exchanged.

If I can suggest an alternate way, if you’re really that concerned about the pool popping out I’d check the local water table and make sure there’s actually a concern. I had mine drained for months during a remodel but I was confident there was no risk.

You might consider draining it half-way before starting the no drain exchange. Then you can be quite confident you got 50% of the existing water out.

 

[Katygreys]

Yea, that's a good point. I mean honestly, there is all this paranoia about pools popping out...but I wonder how the heck pools are BUILT in the first place. Do contractors have to wait till there's a drought?!? Thanks for the feedback.

 

[Bperry]

Yea, that's a good point. I mean honestly, there is all this paranoia about pools popping out...but I wonder how the heck pools are BUILT in the first place. Do contractors have to wait till there's a drought?!? Thanks for the feedback.

If you’re on top of a hill, it’s probably super safe. If you’re on the coast or very close to a natural body of water, maybe want to look into it. Pools can pop out of the ground so it’s not a totally unreasonable thing to consider since penalty for guessing wrong is pretty expensive to fix.

 

[Katygreys]

@jesse-99 Thanks for your replies to my previous post last year (linked in first post of this thread). Hoping I can find an answer to my first question in this new thread:

• Do I need to remove my cartridge filters since I am not using sequestrant and will do a drain and refill?

Thanks!

 

[Newdude]

.but I wonder how the heck pools are BUILT in the first place.

They find water with the backhoe if they don't already know it's there. They sink a well point in each corner to dewater it until the pool is full.

It was a real concern at my last house because we had a 4 ft deep basement for ground water concerns and needed to dig 8 for the pool. If they hit water it was going to add $4k and that was 12 years ago. Everything's gone up a skootch since then.

 

[Katygreys]

Starting AA Tuesday. I bought 3lbs for my 18,000 gal pool from one of the websites listed in the AA Further Reading article. It took several days to arrive. Now starting to get nervous that I may not have enough if the stains are a bit stubborn. I can get the below overnight from Amazon. This should be the exact same thing right?

Amazon.com

a.co

 

[Apsuhead]

I just added AA 2 weeks ago. My pool is similar size and last time and used 3 lbs and it was overkill. I just used 2 lbs this time and it removed everything, although it did take longer to work overnight. I am going to try to remove iron with polyfill in the skimmer so I won’t have to keep buying expensive Metal Magic.