Need to drain & refill, unsure about procedure & have some concerns

[klylor]

Hi there,

I'm in new pool owner & new forum user with an in-ground gunite/plaster pool, and my calcium levels and TDS are quite high, so I understand it's time for a drain & refill. I do not know when the pool was last drained, but it's been at least 4 years.

That being said, I have a feeling it's not as simple as just attaching a submersible pump and letting rip. I am hoping for guidance on potential pitfalls.

My concerns are twofold:
How much of an issue might hydrostatic pressure resulting in a pop be? I live in Tucson, AZ where the water table is low and the rain infrequent. We have had a rainy winter though, and I'm unsure of how long to wait after a rain. I can't exactly dig down to check for water, cause the soil is essentially rock!

Are there any considerations to prevent cracking plaster? Do I need to keep it wet throughout the drain & refill? I have read that I can't drain a pool above 85 degrees.

Anything I'm forgetting?

Perhaps I am overthinking all of it, but wanted to get some advice from y'all. Thanks so much for your time.

 

[ajw22]

@JoyfulNoise can reassure you about Tucson pools popping out of the ground.

Draining - Further Reading

www.troublefreepool.com

 

[JoyfulNoise]

As long as the daytime air temps are below 85°F the plaster should be fine for draining and refilling. Pools don’t float around here, the water table is way too far down. You can drain the pool, LIGHTLY power wash the surface (do NOT use a gas powered high pressure washer or you will regret it), and then refill.

Do not drain and fill before March or else you will negatively impact your sewerage rate with Tucson Water. They calculate sewer rates based on the average uses of the Dec/Jan/Feb water bills.

 

[wireform]

How are you testing the water.

 

[Bperry]

Hi there,

I'm in new pool owner & new forum user with an in-ground gunite/plaster pool, and my calcium levels and TDS are quite high, so I understand it's time for a drain & refill. I do not know when the pool was last drained, but it's been at least 4 years.

That being said, I have a feeling it's not as simple as just attaching a submersible pump and letting rip. I am hoping for guidance on potential pitfalls.

My concerns are twofold:
How much of an issue might hydrostatic pressure resulting in a pop be? I live in Tucson, AZ where the water table is low and the rain infrequent. We have had a rainy winter though, and I'm unsure of how long to wait after a rain. I can't exactly dig down to check for water, cause the soil is essentially rock!

Are there any considerations to prevent cracking plaster? Do I need to keep it wet throughout the drain & refill? I have read that I can't drain a pool above 85 degrees.

Anything I'm forgetting?

Perhaps I am overthinking all of it, but wanted to get some advice from y'all. Thanks so much for your time.

There’s no need to drain a pool because of TDS, but maybe there is if the calcium is super high. I grew up with a pool in CA that was never drained, except when it was replastered 30+ years later. If you got your tests from a pool store I’d get a reliable TFP recommended kit to get more reliable test results. You may not need draining at all.

 

[proavia]

Anything I'm forgetting?

Test results from one of the recommended test kits.
Test Kits Compared

Without quality test results, no telling if a drain/refill is necessary or not.
Since you mentioned high TDS, the results and advice you received are from a pool store.
Pool store results and advice inaccurate and inconsistent at best.

Are you using a SWG for chlorination or another method to properly chlorinate your pool water?
Pool Care Basics
FC/CYA Levels
PoolMath

Inspiration
How Clear is TFP Clear?

 

[dfwnoob]

Don't make any moves with your water until you test it with a proper kit. Pool store testing doesn't work.

Pick up either a Taylor K2006-C or a TFTestKits.net TF100/TF-Pro. Same test reagents, but the TFTestKits models are a much better deal for a residential owner. Get those results and we'll help you craft a plan of attack.

 

[klylor]

Thanks, all! Been unable to get to these replies.

You called it, had my pool water tested by a pool store. But it has not been drained/refilled in at least 5 years and we have really hard water here so I fear calcium deposits. Will order a test kit and go from there. I've got a small window of time before it gets too hot to do it, I think. Temperatures here are creeping into the high 70's. Will order now and hopefully test this week!

Thanks so much for the help.

 

[klylor]

Hey friends,

My test arrived, and just tested this afternoon. I have been paying some folks to handle the chemicals while I deal with all other cleaning/maintenance, but after these tests am thinking it may be smarter (and cheaper!) to do things myself.

Here are my numbers, I used a TF-100 kit:
pH: 7.5
Free Chlorine: 20
Combined Chloramines: 0
Calcium: 1,075 ppm
TA 90ppm
CYA 100-115 ppm (was below the 100 line on the cylinder when I couldn't see the black dot anymore, so am guessing a bit).

What do y'all think?

Again, really grateful for your help & knowledge!

 

[Newdude]

90+ CYA is sketchy to try to decipher. Mix up a batch of 50/50 pool and tap water. Use that as your sample and run the rest of the test as normal. Double the result.

Higher CH can be managed but the CYA requires draining so we need to know exactly how much to drain. Doing so will lower the CH as well. Run a CH test with your fill water too and report back.

Do you have access to softened water ? Many by you tap into it for the pool fill so they don't have to drain every couple years.

Again, really grateful for your help & knowledge!

We still have remnants of the last snow storm on the ground by me. I'm living vicariously through folks like you. THANKS.

 

[klylor]

Thanks Newdude!

Fill water Calcium level is 200ppm. Unfortunately I do not have access to water softening at the moment, thought it looks like there are water softeners that hook onto hoses. Would it be worth getting one of those for filling?

Redid the CYA test as you recommended with half pool/half fill. Got a 60, so doubled would be 120. High!

We still have remnants of the last snow storm on the ground by me. I'm living vicariously through folks like you. THANKS.

And I'll live vicariously through you folks up there when it's 110 here in a few months! Hah!

 

[ajw22]

Thanks Newdude!

Fill water Calcium level is 200ppm. Unfortunately I do not have access to water softening at the moment, thought it looks like there are water softeners that hook onto hoses. Would it be worth getting one of those for filling?

Redid the CYA test as you recommended with half pool/half fill. Got a 60, so doubled would be 120. High!


And I'll live vicariously through you folks up there when it's 110 here in a few months! Hah!

@mknauss uses a portable RV water softener.

 

[Newdude]

it looks like there are water softeners that hook onto hoses. Would it be worth getting one of those for filling?

The hose attachment things don't work and even if they did, you'd go broke spending $30 every 300 gallons. Marty will be around to explain his system shortly.

Got a 60, so doubled would be 120. High!

Ok so a 50% drain would get your CYA to a still high but manageable 60, but with 200 CH in the fill water, would only lower your CH to the 600s.

A 75% drain will get you down to 30 CYA and low 400s CH. If you overshoot that on purpose, to ensure you hit the target, there's not much left to just start over from scratch. But be sure of your water table being low enough and pick a couple of clear days to do it.

 

[mknauss]

Once you get into March, drain the entire pool volume. Refill with regular tap water. That will give you about 250 ppm CH. Then, if you wish to manage your CH rise, you need to use softened water for the bulk of your make up water due to evaporation. I use a RV water softener. It will manage about 16000 grains. Or about 800 gallons of 20 gpg water. In the summer, I regenerate the softener every two weeks or so. You manually regenerate.

I plumbed my water softener into my autofill. I could not put a normal household softener at my equipment pad as I had no where for the regeneration effluent to go.

 

[klylor]

Wonderful, thanks for all the advice everyone. I will do a full drain & refill in the beginning of March while temps are still low. I've got a pump rental squared away, figured out the closest cleanout & checked with the city regulations for drainwater. Will wait until at least a day after it rains, and give a gentle pressure wash.

I have a few spots where plaster has chipped off, I am thinking of applying Patch-it to those spots when it's drained. I also have a few rebar stains, but from my understanding those are a lot more involved to deal with.

Any words of advice for a novice drainer? Things you wished you'd known?

 

[ajw22]

Draining - Further Reading

www.troublefreepool.com

 

[Bperry]

Wonderful, thanks for all the advice everyone. I will do a full drain & refill in the beginning of March while temps are still low. I've got a pump rental squared away, figured out the closest cleanout & checked with the city regulations for drainwater. Will wait until at least a day after it rains, and give a gentle pressure wash.

I have a few spots where plaster has chipped off, I am thinking of applying Patch-it to those spots when it's drained. I also have a few rebar stains, but from my understanding those are a lot more involved to deal with.

Any words of advice for a novice drainer? Things you wished you'd known?

I wouldn’t touch the plaster with any kind of power washer. If the plaster is already failing, even low power pressure washing can pop more of it off. I have experience with that.

 

[klylor]

Thanks again everyone! Will provide some updates after I drain.

 

[klylor]

Updates:

Pool is currently filling back up! Draining process was largely uneventful.

I took the opportunity to patch a few spots where the gunite was showing through plaster, and also in the process found a small spot that sounds hollow when tapped but from my reading on here it sounds like that isn't a big issue unless the de-laminated section breaks off or cracks further. It still seems sound so I decided to leave it for now.

I've previously been using a pool company to do chemicals, but after feeling confident testing/draining/patching I am thinking it makes sense to take over the chemical balancing. That being said, I've been doing some reading on the forums, but just want to confirm: in terms of balancing new fill water, it's primarily CYA (brought up to 30ppm) and liquid chlorine I need to add, right? (Assuming alkalinity is okay).

Any tips on calculating volume to determine chemical amounts? My pool is a bit oddly shaped.

Appreciate the support from everyone, you gave me a lot of confidence to proceed!

 

[ajw22]

Calculators - Further Reading

www.troublefreepool.com