New care for my old pool

[i86time]

Hello all. I'm new to caring for my 17,000 gal plaster pool/hot tub, though I've owned it for almost 9 years. When we moved in, we kept the previous owner's pool service and just rolled with it; having someone else do the work was the one luxury I allowed myself (besides paper towels). However after the sale/transfer of our contract to two others, the monthly cost rose to double what it originally was. Last year I looked into a new pool co and thought I found a good deal, but he just isn't panning out, so I've decided to take it on myself. I'm slowly learning the basics....

The pool has always looked good (except for the floor which our newest pool guy infrequently vacuums/sweeps), but this past year I've noticed the water does not feel as nice as it used to. Over the past couple months I've also noticed that dark spots have formed on multiple areas of the floor. From above, it appears like small stones/dirt or dark debris has settled, but when swept it does not move, so it's on the plaster (I'll get a better look soon when it warms up just a bit more for a trip to the bottom). Any idea what could cause this?

I've also been considering a switch to a SWG for a while and believe I will move ahead with it. I asked the local shop, who seem very helpful, if anything special needs to be done with the chemistry before installing, and they said no. Is that the case?

I purchased my first chem test kit (Taylor) and took readings a couple days ago (water temp 72 degF):
FC - 10 ppm
TC - 10 ppm
pH - 7.8
TA - 150 ppm
CH - 350 ppm
CYA - 100 ppm (I redid this using the half sample/mix w/ tap water and then got between 70-80 ppm)
Salt - 600 ppm (I did this to estimate startup salt needed)

Looking at the Pool Math calc, using TFP and trichlor (current setup), those numbers seem off. Should FC and CYA be that high? Being in So CA, we don't close our pool (open to opinions on if we should) and we haven't yet been using the pool this season. The pool guy uses trichlor in the skimmer basket and I've seen him add both a clear liquid and blue liquid at various times, not sure what either are. TA is also high, correct? Should I go through with adding acid to lower TA prior to install of SWG? Thanks for any tips and info, looking forward to learning a lot here and maintaining the pool on my own.

 

[PoolStored]

Welcome to TFP!!!

You have quite a bit going on....

1. Do not put pucks into the skimmer (tri-chlor) It is acidic and will damage the skimmer and equipment. Remove all pucks for now.
2. With a CYA of 160 (2x diluted 80), it is not possible to sanitize this pool.
3. The dark spots are likely algae.
4. You should not have pool maintenance people adding clear and blue liquids, or anything else to the pool.

You need to replace about 70% of your pool water to reduce CYA to around 50. Read "no drain water exchange", section 1.6.

Draining - Further Reading

www.troublefreepool.com

I would start the process of replacing water.

After that, we will start this process...print it out, read it three times, keep in your back pocket. Link-->SLAM Process

 

[Texas Splash]

Welcome! Good job taking control of your pool and testing. A whole new world has just opened up and now you can see exactly what has (or has not) been getting done with that old pool service. Your situation to exchange some water is very common to new TFP members who simply followed someone else's advice. Once you get this under control, pool like will be MUCH easier. Once you exchange enough water to lower the CYA, post back with a new set of test results and we'll go from there.

Be sure to bookmark our Pool Care Basics and let us know if you have any questions along the way.

 

[i86time]

Welcome to TFP!!!

You have quite a bit going on....

1. Do not put pucks into the skimmer (tri-chlor) It is acidic and will damage the skimmer and equipment. Remove all pucks for now.
2. With a CYA of 160 (2x diluted 80), it is not possible to sanitize this pool.
3. The dark spots are likely algae.
4. You should not have pool maintenance people adding clear and blue liquids, or anything else to the pool.

You need to replace about 70% of your pool water to reduce CYA to around 50. Read "no drain water exchange", section 1.6.

Draining - Further Reading

www.troublefreepool.com

I would start the process of replacing water.

After that, we will start this process...print it out, read it three times, keep in your back pocket. Link-->SLAM Process

Thank you fort the welcome and quick reply. RE: your points
1. We had a chlorine basket, but it cracked a couple weeks ago, though the pool guy was putting pucks in the skimmer basket long before. I'll be supplementing with liquid CL once the SWG is in, per recs here.
2. To clarify, the adjusted CYA on the 2nd test (2 days after the first) was 70-80 ppm (about half way between the 30 - 40 ppm mark on the diluted sample), so definitely not 160 ppm. I read this was high for trichlor, but should be on the OK/high end for SWG.
3. Will the algae go away with corrected chemistry? It is not coming up via brushing so far.
4. I don't think he's done much of anything recently. I only found out about the blue stuff because he splashed it all over the concrete deck and it was stained for a few days.

Given the above correction on CYA, according to the Pool Match calc, I need to replace 38% (6400 gal) to get down to 50 ppm. Again, to clarify, since I'll be installing a SWG, do I want to get CYA that low?

 

[PoolStored]

Thank you fort the welcome and quick reply. RE: your points
1. We had a chlorine basket, but it cracked a couple weeks ago, though the pool guy was putting pucks in the skimmer basket long before. I'll be supplementing with liquid CL once the SWG is in, per recs here.

Get them out and use liquid for now.

2. To clarify, the adjusted CYA on the 2nd test (2 days after the first) was 70-80 ppm (about half way between the 30 - 40 ppm mark on the diluted sample), so definitely not 160 ppm. I read this was high for trichlor, but should be on the OK/high end for SWG.

Whew!!!! That helps.

3. Will the algae go away with corrected chemistry? It is not coming up via brushing so far.

No, we are going to follow this process. Link-->SLAM Process

Print it out, read it three times, keep in your back pocket!!

4. I don't think he's done much of anything recently. I only found out about the blue stuff because he splashed it all over the concrete deck and it was stained for a few days.

Cool. Don't let him do anything or add anything to the pool.

Given the above correction on CYA, according to the Pool Match calc, I need to replace 38% (6400 gal) to get down to 50 ppm. Again, to clarify, since I'll be installing a SWG, do I want to get CYA that low?

CYA is easy to add, have to replace to get it out. CYA is not hard and fast number. You can run it at 50 - 80.

Yes, I would replace the 6400 gallons. Will help with the slam. Read section 3.5, no drain water exchange on how to exchange water. After the exchange is done, start the SLAM process.

Draining - Further Reading

www.troublefreepool.com

 

[i86time]

Thanks again for the reply. I've ordered a utility pump and will start draining.

I was able to get in the pool today and the discoloration is not algae (makes sense given the high FC). There are 4 different stains/discolorations. The first appears to be the concrete under where the plaster lining has dissolved/worn away. When we purchased, the pool had a half dollar sized area like it. That doesn't appear to have gotten much larger, but there are now at least two other similar, smaller areas that I notice. I do notice many small plaster pieces on the floor and areas on the wall where it is wearing away, but does not appear to be down to the concrete.
Then there is at least one spot that is a dark blue, like an ink stain. Not sure what caused it.
There are multiple small areas that look like rust, a brownish-red dark outline with a slightly lighter center or just an outline alone.
Multiple areas with small dark brown/black spots, like freckles. Many are on the steps, which I have noticed for a while, but now I am seeing them deeper in the pool.
I took a brass wire brush to all of these and nothing came off.

According to permits, the pool was built in 1985 and I'm not sure if it has ever been re-lined. Guess it's just old.

Oh and on the SLAM link you provided, the CYA/FC table is no longer linked, it's just a widget that asked for sanitizer type and CYA level and returns min and target FC levels, but not FC shock level.

 

[clambert1273]

Thanks again for the reply. I've ordered a utility pump and will start draining.

I was able to get in the pool today and the discoloration is not algae (makes sense given the high FC). There are 4 different stains/discolorations. The first appears to be the concrete under where the plaster lining has dissolved/worn away. When we purchased, the pool had a half dollar sized area like it. That doesn't appear to have gotten much larger, but there are now at least two other similar, smaller areas that I notice. I do notice many small plaster pieces on the floor and areas on the wall where it is wearing away, but does not appear to be down to the concrete.
Then there is at least one spot that is a dark blue, like an ink stain. Not sure what caused it.
There are multiple small areas that look like rust, a brownish-red dark outline with a slightly lighter center or just an outline alone.
Multiple areas with small dark brown/black spots, like freckles. Many are on the steps, which I have noticed for a while, but now I am seeing them deeper in the pool.
I took a brass wire brush to all of these and nothing came off.

According to permits, the pool was built in 1985 and I'm not sure if it has ever been re-lined. Guess it's just old.

Oh and on the SLAM link you provided, the CYA/FC table is no longer linked, it's just a widget that asked for sanitizer type and CYA level and returns min and target FC levels, but not FC shock level.

Here ya go

 

[PoolStored]

I was able to get in the pool today and the discoloration is not algae (makes sense given the high FC). There are 4 different stains/discolorations. The first appears to be the concrete under where the plaster lining has dissolved/worn away. When we purchased, the pool had a half dollar sized area like it. That doesn't appear to have gotten much larger, but there are now at least two other similar, smaller areas that I notice. I do notice many small plaster pieces on the floor and areas on the wall where it is wearing away, but does not appear to be down to the concrete.
Then there is at least one spot that is a dark blue, like an ink stain. Not sure what caused it.
There are multiple small areas that look like rust, a brownish-red dark outline with a slightly lighter center or just an outline alone.
Multiple areas with small dark brown/black spots, like freckles. Many are on the steps, which I have noticed for a while, but now I am seeing them deeper in the pool.
I took a brass wire brush to all of these and nothing came off.

I would not worry about the stains at the moment, I would focus on the slam. Why? You will get rid of the immediate problem, algae. Second, the slam may help some of those stains if the are organic. Third, you can't fix any of the staining with Algae in the pool.

When you are ready for stain identification...we got you covered.

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

 

[i86time]

Here ya go
View attachment 500393

Thanks for that. I found a post here with a table with the SLAM level, but wasn't sure if that was the currently recommended one.

 

[i86time]

I would not worry about the stains at the moment, I would focus on the slam. Why? You will get rid of the immediate problem, algae. Second, the slam may help some of those stains if the are organic. Third, you can't fix any of the staining with Algae in the pool.

When you are ready for stain identification...we got you covered.

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

Thank you for the reply. Just to be clear, I see no algae in the pool.

 

[PoolStored]

Thank you for the reply. Just to be clear, I see no algae in the pool.

Let's reboot the narrative. At first, maybe my mistake or communication, your CYA was 160. Cleared that up. CYA 80. Check...

You have spots on the pool. Stains can be organic, iron, copper, shells in the aggregate...lots of options...

A good guide to get you started:

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

Can you post pictures?

Should FC and CYA be that high?

Your CYA is 80. 10FC is great for CYA of 80...always follow this...Link-->FC/CYA Levels

Should I go through with adding acid to lower TA prior to install of SWG?

Not necessary. SWCG is pH neutral. You can lower before or after, or leave it alone. The only thing that high TA does is increase pH rise, requiring muriatic acid additions. Manage your pH (keep it in the 7s). TA will come down over time.

 

[i86time]

Let's reboot the narrative. At first, maybe my mistake or communication, your CYA was 160. Cleared that up. CYA 80. Check...

You have spots on the pool. Stains can be organic, iron, copper, shells in the aggregate...lots of options...

A good guide to get you started:

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

Can you post pictures?

Your CYA is 80. 10FC is great for CYA of 80...always follow this...Link-->FC/CYA Levels

Not necessary. SWCG is pH neutral. You can lower before or after, or leave it alone. The only thing that high TA does is increase pH rise, requiring muriatic acid additions. Manage your pH (keep it in the 7s). TA will come down over time.

OK, glad things are clearer, this is all still new for me. I see from the TFP FC/CYA widget, a FC of 10 ppm and CYA of 80 ppm is OK, but what was going through my mind is that it's not the 3ppm/50 pmm the Pool Match calculator indicates for the TFP suggested levels. Again, since I'll be going to a SWG, I'll just leave it be. Should I still do a water exchange, as that may effect all this? We've never done one in the almost 9 years we've owned the pool and the pool store claimed it should be done every 7 to 9 years.

 

[i86time]

Attached are photos of the stains. The first is of the top entry step. The light brown larger "blotches" have developed over time, the smaller, darker spots are the ones that are more recent. I can start a thread in a more appropriate subforum if needed, I was just unsure if the pool chemistry was causing any of these. I am seeing the plaster wearing away in multiple spots, but only a few are down to the concrete.

 

[PoolStored]

I see no algae in the pool.

For insurance, especially with a CYA of 80, I would do an Overnight Chlorine loss test for grins...cheap couple tests...Link-->Overnight Chlorine Loss Test

what was going through my mind is that it's not the 3ppm/50 pmm the Pool Match calculator indicates for the TFP suggested levels. Again, since I'll be going to a SWG, I'll just leave it be.

Poolmath. Make sure you are logged in the the same ID/Password as TFP. Go to the home screen, click on the gear in upper right. Scroll to the bottom and we can see your logs, helps with troubleshooting.

Suggested levels. Enter your CYA of 80 and your FC suggested levels should change (PoolMath). 80ppm in a liquid chlorine pool are not recommended for a number of reasons. It is harder to SLAM. SWCG makes chlorine all the time, Liquid Chlorine, people usually dose once a day...easier to let your FC drop into Algae land.

Should I still do a water exchange, as that may effect all this? We've never done one in the almost 9 years we've owned the pool and the pool store claimed it should be done every 7 to 9 years.

There are few reasons to exchange water, time is not one of them. High CH (not you), Bacqucil (not you), Metals (not you at this point), HIGH CYA (you...IF you have algae...if don't have algae and can keep your FC up through SWCG startup, 80 is a nice place to be. Do the OCLT and see what your result is.

 

[PoolStored]

Attached are photos of the stains. The first is of the top entry step. The light brown larger "blotches" have developed over time, the smaller, darker spots are the ones that are more recent. I can start a thread in a more appropriate subforum if needed, I was just unsure if the pool chemistry was causing any of these. I am seeing the plaster wearing away in multiple spots, but only a few are down to the concrete.

Maybe...was Abalone shell used in the plaster mix? (pic 1)
Maybe rebar rust. Take some vitamin C pills, put them in a sock and crush them up...see if that takes those 2 spots in pic #2.
Pic 3 looks like a tooling mark...are the indents in the pool? Pic 3
Same with pic 4
Pic 5 looks like pic 2.

I would do the vitamin c sock on all the spots and note if you see a change.

 

[i86time]

Maybe...was Abalone shell used in the plaster mix? (pic 1)

I'm not sure, the pool was here long before we were

Maybe rebar rust. Take some vitamin C pills, put them in a sock and crush them up...see if that takes those 2 spots in pic #2.
Pic 5 looks like pic 2.

I would do the vitamin c sock on all the spots and note if you see a change.

OK, I'll try that.

For insurance, especially with a CYA of 80, I would do an Overnight Chlorine loss test for grins...cheap couple tests...Link-->Overnight Chlorine Loss Test

I'll give that a shot. Only issue is, the Taylor test kit only has color samples for 1, 2, 3, 5, 7.5 & 10 ppm. I take it if I'm @ 10ppm for the first test, as long as the color doesn't dip to the 7.5, that's still OK? It could be more than a 1 ppm drop, but I wouldn't be able to detect it.

 

[PoolStored]

I'll give that a shot. Only issue is, the Taylor test kit only has color samples for 1, 2, 3, 5, 7.5 & 10 ppm. I take it if I'm @ 10ppm for the first test, as long as the color doesn't dip to the 7.5, that's still OK? It could be more than a 1 ppm drop, but I wouldn't be able to detect it.

The only way to reliably do the OCLT is with the FAS-DPD test included with the K-2006 test kit, or with the independent K-1515 kit. I'm sorry I didn't notice you had the K-2005. The only difference between the K-2005 and K-2006 is the FAS-DPD test.

 

[PoolStored]

I take it if I'm @ 10ppm for the first test, as long as the color doesn't dip to the 7.5, that's still OK?

You might try it. If the colors are a bit off, get the K-1515. I'd still opt for the FAS-DPD to be sure.

You might review this...Link-->Test Kits Compared

 

[i86time]

OK, I've ordered the K-1515. Just so I understand, if the OCLT shows no loss, then I should not do any water exchange? So basically I am good to go for the SWCG install at my current levels? Even though my FC was @ 10 ppm, it'll fall down to 3 ppm with sun degradation/pool use. And if it doesn't fall, I just lower the SWCG production or turn it off until it does, monitoring properly of course?

 

[PoolStored]

OK, I've ordered the K-1515. Just so I understand, if the OCLT shows no loss, then I should not do any water exchange?

Yeah.

So basically I am good to go for the SWCG install at my current levels? Even though my FC was @ 10 ppm, it'll fall down to 3 ppm with sun degradation/pool use. And if it doesn't fall, I just lower the SWCG production or turn it off until it does, monitoring properly of course?

That is the beauty of SWCG. It doesn't fall. SWCG makes chlorine anytime it runs. My CYA is 70 and my FC stays a nice 8,9,10...just turn up or down a bit as needed