Lap pool neglected for 7 years - DIY re-opening

[volcano]

Hi all! I've used these forums and Pool School in the past for seasonal Intex (in my signature block), but my parents just moved into a house with a lap pool that has been covered and neglected for seven years. Hoping to DIY the resurrection of this pool.

The pump/filter is currently off and the lines are capped. It's a cartridge filter (can get specs on that a bit later, not at the pool right now). I'd like to turn that on ASAP but need to make sure all lines are uncapped etc. first.

This morning I pulled off the cover for the first time and as fully expected, it's very green

1. Volume estimate (~45.5 ft long, ~12 ft wide, ~5 ft deep) is approximately 20,000 gallons (maybe closer to 18,000-- I need to get a better depth profile) 16,000 gallons.
2. Vinyl liner.
3. We stirred the pool a bit with the skimmer net-- I'm assuming it's pretty stratified at the moment.
4. After stirring, tested using the reagents I bought last year: FC = 0 (no surprise), CYA = 0 (bit surprised by this?), pH = 7.2 (I assume this will increase once we aerate the pool).
5. I'm nervous about adding CYA until I confirm the CYA = 0 result. Hoping to purchase a CYA test kit at the local pool store (otherwise I'll order one, but would like to do this today)-- my reagents sat all winter in the (unheated) garage; not sure how well the CYA reagent (from TFTestkits) can handle freeze/thaw cycles?
6. I assume the priority should be to add multiple gallons of chlorine to at least start killing what's currently growing-- that's my first plan for today. PoolMath says ~3 gallons will bring us to 10 ppm FC if we had 40 ppm CYA, but I know the chlorine will be consumed nearly immediately by the algae (and if CYA really = 0 then we need to fix that ASAP too).
7. Simultaneously, I'll look into starting up the pump.

Any advice as we embark on this adventure? Thanks!

 

[V___25]

Typically, a good test kit and adding liquid chlorine and cya would be job 1 based on test results. But before you start adding chemicals, is the liner is good shape? Being it sat for 7 years unmaintained, I'm wondering if it's still even good. Liners typically last 10-15 with good maintenance and who knows when it was put in. Clearly it's holding water but is it still soft flexible or dry and brittle? I'd hate to you go through the whole process if the liner isn't sustainable. It looks ok from the picture, but just checking.

 

[volcano]

Typically, a good test kit and adding liquid chlorine and cya would be job 1 based on test results. But before you start adding chemicals, is the liner is good shape? Being it sat for 7 years unmaintained, I'm wondering if it's still even good. Liners typically last 10-15 with good maintenance and who knows when it was put in. Clearly it's holding water but is it still soft flexible or dry and brittle? I'd hate to you go through the whole process if the liner isn't sustainable. It looks ok from the picture, but just checking.

Thanks for checking! Pool company came out yesterday to measure for a new liner for next year, and they said this one looks totally fine for this year. Ultimately it'll need replacing, but they saw no reason we can't squeeze one more year out of this one.

 

[IceShadow]

First step is to get the equipment running. Without that you are going to struggle to keep the water well mixed.

Next step is to make sure you don't have ammonia. Add enough FC to take it to 10ppm, mix for 15 minutes, test. If it has any FC, you're probably good to add CYA. If it's 0 FC (and likely higher CC) then you have ammonia in the pool and potentially the bacteria that converts CYA to ammonia. Then you have to keep adding FC until it holds, at which point the ammonia has been burned up by the FC and the bacteria should be dead from the FC level as well.

Before doing all of that, if the FC doesn't hold after the first addition, it might be worth it in a pool that's sat that long to get an ammonia test, likely from an aquarium store. Then you'll have an idea of the ammonia ppm in the pool. If it's elevated enough, you might decide it's better to exchange the water instead of trying to get rid of all the ammonia with FC, depending on how much FC it would take to get rid of the ammonia.

My understanding is that the CYA reagent is the most stable out of all of the reagents, but it will still have a shelf life.

 

[kul]

Wow that’s a super yucky situation. Following because I want to see you bring it back to life!! I love these drab to fab threads! Good luck!!

 

[volcano]

First step is to get the equipment running. Without that you are going to struggle to keep the water well mixed.

Next step is to make sure you don't have ammonia. Add enough FC to take it to 10ppm, mix for 15 minutes, test. If it has any FC, you're probably good to add CYA. If it's 0 FC (and likely higher CC) then you have ammonia in the pool and potentially the bacteria that converts CYA to ammonia. Then you have to keep adding FC until it holds, at which point the ammonia has been burned up by the FC and the bacteria should be dead from the FC level as well.

Before doing all of that, if the FC doesn't hold after the first addition, it might be worth it in a pool that's sat that long to get an ammonia test, likely from an aquarium store. Then you'll have an idea of the ammonia ppm in the pool. If it's elevated enough, you might decide it's better to exchange the water instead of trying to get rid of all the ammonia with FC, depending on how much FC it would take to get rid of the ammonia.

My understanding is that the CYA reagent is the most stable out of all of the reagents, but it will still have a shelf life.

This is super helpful, thanks! Will try this today. Yesterday was mostly dealing with hardware rather than chemistry.

• Removed all winterizing plugs (black rubber expansion plugs, darn near impossible to remove!)
• Reinstalled the four cartridge filters (there were two sets of filters; I used the set that looked least-bad). Filter assembly is a Hayward Super Star C-3000.
• Ignoring the heater for now. It's a StaRite SR200NA (natural gas) and appears to be toast (or at least the electronics board is toast-- missing buttons, exposed electronics, etc.). No obvious way to bypass the heater/remove it from the flow path, so I figured water could just flow through it (unheated) for now.
• Turned on the pump, a Magnetek Century Centurion 1081- it's turned right on and purred nicely, but no water started flowing. I read that it was self-priming, but maybe "self-priming after seven years" isn't a thing
• The pump has its own small skimmer basket (adjacent to the pump); filled that with water to try priming the system and turned the pump on again.
• Water started flowing! And then started gushing out of the heater, which is apparently missing two plugs (one from the bottom of the heater pump (a booster pump?) and one from the bottom of the heater itself).
• Closing the knob labeled RETURN stopped the flow to heater (but water was still moving through the pump and filter, so clear that's not the ONLY return).
• Let everything run for a bit and the pump/filter seemed to be operating well. Pressure on the filter held steady at 15 psi, I kept checking it with the plan to wash the filters when pressure rose 7-10 psi.
• Found another valve labeled "MAIN DRAIN" and opened that one-- presumably this is a drain at the bottom of the pool? Pressure on the filters rose from 15 psi to 20 psi with this opened.
• With everything circulating, added 2.5 gal of 12% Cl (will add much more today! and do the NH3/FC test that IceShadow recommended).
  Water now flows out through the two skimmers (presumably also out of the floor drain) and back into the pool via two of the return jets. No water is flowing through the other four return jets. I'd like to open the knob labeled RETURN and see if that helps, but can't do that until we find appropriate plugs for drains in the heater and heater booster pump.
• Pressure rose a few psi after a few hours of running, turned everything off when we went to bed since we wouldn't be monitoring pressure overnight.
• Plan for today: rinse the filters, turn the system back on again, add more Cl, do the FC/NH3 test, keep adding Cl and rinsing filters as needed! And try to figure out what plugs are needed for the heater assembly. Also, buy some frog logs...

Pics attached - stubborn winterizing plug, top panel of heater, cartridge filters, and water from one of the two functional return jets-- very bubbly at first but eventually bubble-free).

Again, all advice and suggestions are greatly appreciated!

 

[volcano]

Chlorine update:
Big surprise, we've still got some FC this morning!
Seeing 10 ppm FC (higher than I expected) and 1 ppm CC (way lower than I expected).
Based on that and what IceShadow said above, I think we're good to add some CYA. Pool volume is a bit lower than I thought (around 16,000 gallons). PoolMath suggests 64 oz of dry CYA will bring us to 30 ppm, so I might start with that and see how it goes.

 

[volcano]

Visual update, I know the appeal in these threads is in the pics

 

[volcano]

There's an in-line "chlorine feeder" (see pic) for tri-chlor pucks. Aren't these a problem because they result in sky-high CYA? Should we just remove this thing and cap the lines to/from it?

 

[V___25]

Tabs as an ongoing method of chlorinating your pool aren't recommended because as you said, they result in high CYA and based on the FC/CYA chart, the needed FC becomes unmanageable when CYA is that high.
Tabs have their place if you're going on vacation or something and want throw a few in a floater if your CYA can take the hit so they aren't all bad. But it's up to you what you want to do with that thing. We just removed ours this past weekend because it was leaking but for the past 2 years, we just ignored it. You can cut it out and run new plumbing, or just bypass it.

 

[Flying Tivo]

You could remove the filter cartridges for now, until you are in SLAM mode. Unless you dont mind cleaning them every 30 min. Make sure you remove all large debris with the net. Very careful while scrubbing the liner as to not create a tear. Stock up on liquid chlorine, 20 gallons at least.

 

[volcano]

You could remove the filter cartridges for now, until you are in SLAM mode. Unless you dont mind cleaning them every 30 min. Make sure you remove all large debris with the net. Very careful while scrubbing the liner as to not create a tear. Stock up on liquid chlorine, 20 gallons at least.

If I remove the cartridges, though, there won't be any filtration happening right? Other than the skimmers, which are only grabbing big stuff.

 

[Flying Tivo]

Exactly, which is what you need for right now, big things. Until you start the SLAM Process and the pool turns BluishGray then you can start filtering Dead algae. Live algae can not be filtered.

 

[volcano]

Exactly, which is what you need for right now, big things. Until you start the SLAM Process and the pool turns BluishGray then you can start filtering Dead algae. Live algae can not be filtered.

Depending on what you mean by "big," we might already have that covered! The pool was covered with a tight-fitting safety cover and there are virtually no twigs/leaves in it. Yesterday we scooped out a few large plants (looked like milfoil or something in that family). Everything that we stir up from the bottom now is just big plumes (presumably dead algae?), small enough that most of it flows right through the pool skimmer. No longer getting big chunks in the pump skimmer, either.
We put some skimmer socks into the skimmer baskets (waiting on hair nets).

 

[volcano]

Complicating factor: the pool will need to be left unattended for the next two days (unavoidably). Not going to leave the pump running while we're gone since we won't be able to monitor the system. We'll put the safety cover back on before leaving. How high can we safely bring the FC, assuming that it will be mostly consumed over the next two days? Got about 20 ppm CYA in here at the moment.

 

[Flying Tivo]

SLAM levels but not higher.

 

[volcano]

We'll keep working on maintaining SLAM levels and bringing up the CYA (dissolving slowly in cold pool water!).

Next priority seems to be pH and alkalinity.
Current conditions:
pH = 7.2
Total alkalinity = 20 ppm (SUPER low! 7 years of rainwater, I guess).

My understanding is that we want TA to be 80-120 ppm; PoolMath suggests 14 pounds of baking soda to bring this to 80 ppm. That seems like a lot!

 

[MITBeta]

I would go slow on the baking soda because A. I see you don't seem 100% sure about the volume, B. you want to see how your pH reacts, and C. you may not need to go to 80.

Aim for 50-60 to start.

You also can't measure pH accuracy at SLAM FC levels, so I would be cautious of doing things that will alter it during SLAM.

 

[volcano]

I would go slow on the baking soda because A. I see you don't seem 100% sure about the volume, B. you want to see how your pH reacts, and C. you may not need to go to 80.

Aim for 50-60 to start.

You also can't measure pH accuracy at SLAM FC levels, so I would be cautious of doing things that will alter it during SLAM.

Thanks MITBeta, this is really helpful! Maybe we toss in one (two? three? more?) pounds of baking soda just to get started, and then see how the test results change. Or should we ignore everything everything except FC (and a bit of CYA) for now?

 

[IceShadow]

You don’t want the pH to crash so if you’re getting 20 for TA I would go ahead and add some baking soda. Maybe then let FC drift down to 10 and test pH, adjust the pH as needed, and go back to SLAMming.