New Old House, New Old Pool....

[Oly]

And possibly old water.....

Great site, thanks in advance for the brain power.

Recently we bought a custom home built in 1950 which has an older rectangular 30,000 gallon concrete/plaster pool that was resurfaced with fiberglass 7 years ago.

It has a Pentair48 diatomaceous earth filter and supposedly a copper return line but this is not verified yet. I have replaced the grids and purchased a suction side Rebel sweeper with an inline leaf canister. I remove debris from the surface daily with a leaf net and the water is clear and water temps are approaching the high 80's.

I ran water tests to the local pool supply but had varied results coupled with bad advice and misspent money on my behalf, oh well.

I stepped up and upgraded my test kit to a Taylor K2006 and the numbers were as follows:

Free Cl 1.4 (morning test with night treatment)
Combined Cl .6
pH 7.4
TA 130
Ca Hardness 325
CYA 160


Previous owner and hired pool guy used trichlor tabs in a floater.
I have released the pool guy and use 10% bleach from Home Depot and upped the nightly rate to 1 gallon from the 80 ounces I started with. The pool will use half the chlorine over night it seems.

I found the pool math calculator and have determined I need to drain my pool 80% to get my CYA levels down. My recommended free Cl level calculated to a minimum 11 with a liquid chlorine requirement at over 2.5 gallons. Ouch $6.50+ a day for a minimum level free Cl and no possibility of a SLAM. I do intend to add the 2.6 gallons after sunset tonight and monitor the Chlorine so I will update this post. I also will begin to research the pool draining process as I would like to get the CYA down and enjoy new water and cooler water temps for a bit.

Now my lying eyes see a clear pool, not crystal clear but clearly see the bottom of 9' deep end and only tiny floaters at night with the pool light on. There is some bottom debris each morning, what I assumed to be pollen from a 25' flowering Privit tree up wind of my pool. After reading the mustard algae topic I am uncertain if it is pollen but it is not adhered to the pool, not on the pool sides and not limited to the shade side. The small opaque bb sized globs do settle on the bottom, are easily disturbed but readily vacuum up. The fiberglass pool surface is much smoother than plaster, is very nice on the feet and does not allow adhesion of any debris.

Any thoughts?

Also how do you apply liquid chlorine when you are away for vacation?

I suppose getting my CYA levels down would allow me to use the tabs when on vacation but conditioners with CYA appear to be a one way problem in the long run. Why no tabs without CYA?

Thanks again for the site.

 

[PAGirl]

What are you dosing to at night, and how much are you losing by morning? If your pool is slightly cloudy, you're losing more than 1 ppm of chlorine overnight and you see silt in the morning, you would need to perform a SLAM. (It would be advisable to do so after the reduction in CYA.)

You are correct about the vacation use of tabs. If you lower your CYA enough, you have a little wiggle room. It's good to find the sweet spot for your pool, not too low that you lose a lot of chlorine to the sun, not too high that you need to use a higher level for your chlorine to avoid algae.

 

[Oly]

OK realized my liquid Cl is 10% not 12.5%.

So last night added 3 gals 10% and Free Cl tested at 8ppm. I added another gal. Checked in AM and Free Cl was 6ppm with combined Cl at 0.5ppm.

No material precipitated out to the bottom and the wind was calm so now I am thinking pollen not algae, but not certain yet. The water is clear maybe a bit of haze at night with the pool light on but very slight.

Following the calculater I should be keeping the FCl at 11ppm. Have I just been lucky because I have kept the FCl between 3ppm and 0.5ppm for months without any greening using only 80 oz of 10%. When temps rose in July I upped the 10% to 1 gal each night and after 24 hours the levels dropped to 0.5ppm.

So I will attempt to keep my free Cl higher and work toward a drain and refill to lower the CYA.

Is there a dry chlorine that does not have CYA or calcium?

How do you folks maintain Free Cl using liquid when on vacation? Is there an injection system that allows bulk use?

 

[PAGirl]

With a loss of 2 overnight, you really should perform a Pool School - SLAM - Shock Level And Maintain

Pool School - Chlorine / CYA Chart

 

[CJadamec]

There are bulk liquid chlorine injection systems they are often referred to as stenner pumps.

The other option to automatically chlorinate a pool is to add a salt water chlorine generator. Once you have a handle on the rest of your water chemistry a salt water system is very easy to maintain.

Both a stenner and a SWG will maintain chlorine while you are on vacation. There are some on here who have been away as much as a month with a SWG and returned to a clean and clear pool. To get results like that you will need to work on that CYA.

Priority one for you is to lower your CYA and get the algae issue you currently have under control. I know being in CA makes that much of a water exchange difficult and expensive but with a CYA of 160 your pool will be very hard to maintain and keep clear.

 

[Oly]

OK thanks PAGirl and CJadamec for the information. Yes I now realize there is no work around for a very high CYA level. With this high CYA getting free chlorine sanitation levels to the desirable level is expensive and attempting a SLAM near impossible it seems. So I will bring down the CYA the old fashioned way.

Working toward a drain and refill now.

Questions as I look forward:

What CYA level should I shoot for living in sunny and hot central CA? Will 30-40ppm work here? How fast do trichlor tabs raise the CYA levels if say I use them for vacation use and long weekends away only?

Any tips regarding pool draining for a newby? Have no water table issues here but it is hot out. I can rent a pump at Home Depot. How long to drain a 30,000 gal pool you think?

Thinking of changing out my pool light with and LED during this process, good idea? Any tips?

Thanks again for following along and here are a couple of pictures.

Thankfully I have avoided the green bloom and not sure if these "balls" are algae or pollen but know enough now to get a drain and refill underway.

 

[Flying Tivo]

If your filter has a drain to waste setting, then you could drain using your pool pump. If not, then you will need to rent a submersible pump and start draining. The bigger the pump the faster it will go. Poolmath says you need to drain at least 81% of your pool, so aim for that. Make sure you dont overburden your drain pipes and create a problem further down the line with neighbors, or you can water your lawn or neighbors lawns, they will appreciate it. LED light are great for energy bill, you will notice it.

Felipe

 

[Oly]

Thanks Flying Tivo.

No drain to waste setting for me. In fact I will be renting a pump and pushing the water down the driveway and into the street. Have the OK from the City Public Works and Flood Control District. Green lit for Friday now just have to talk with the down-stream neighbors and assure them the plant watering is free.

 

[CJadamec]

Only word of advise I have for you is to have everything lined up and ready to go for when the pool is dry. If you are doing lights have them on hand and ready to install. If you plan on scrubbing the pool have your brush and a supply of chlorine ready. Try to keep the pool empty for as little time as possible.


Use pool math and stock up on enough CYA to get to 30ppm and have bleach ready to add FC to your new water. Once you get your pool filled and pump running start dissolving your CYA and add the bleach (based on a 30ppm level of CYA) to the pool. Do a full set of water tests and then work on getting your pH dialed in and make sure your TA and CH are in line. When changing the pH and TA take it easy and go slow until you get a feel for how your pool responds there will be a delay between adding the chemicals and the final result in water change. Its a good idea to only use half as much chemical that pool math suggests when making the first big adjustments to pH and TA.


There are a lot of folks around here who use trichlor tabs in a floater when they are away for a weekend to maintain FC. The tabs aren't inherently an evil thing so long as you understand that the tabs are adding CYA every time you use them. With the pucks for every 1ppm of FC you add you will get about 0.6pmm of CYA. So if your pool is using 2-3ppm of FC a day which is pretty normal. If you use pucks to keep up with that rate of FC loss you will add 1.2-2ppm of CYA each day you are on pucks. So for a long weekend you will add from 4-6ppm of CYA. If you are testing regularly with a good test kit and you know the proper FC level for your current CYA then you will do just fine.

 

[Oly]

Thanks CJadamec, good advise.

Why not have a trichlor tab without the CYA or at least at a much lower level?

When I first started with this pool in the early spring (before I found this site) I could not get the FC to register using the pucks and I was stuffing 3 of them in my floater and checking it after 3-4 days to keep it full. I did shock the pool a couple of time using the dichlor powder but the FC levels did not rise much above 5ppm. I had to use at least 1# of the shock powder (dichlor) in addition to the pucks to get any reading on my cheap test kit. I rarely had the FC above 2 and it was at 0.5 or less by the end of 24 hours and this went on for over a month. I am amazed the pool did not go green and looks as good as it does. I transitioned to using 10% but kept the FC levels at what I thought was in the ideal range before I understood the association with CYA. Once educated I upped the FC to 12+ for several days and brushed the walls but I am still experiencing the opaque gelatinous balls that settle on the bottom when the pump is off for some time although the amount has been reduced. Regarding the water clarity it seems to cloud a bit after I add the 10% at night with the light on but by morning it looks pretty clear although I can see some particle suspension when underwater with a mask. I know from my FC loss overnight that I am burning though the FC although the CC is always at 0.5ppm.

So I suspect I do have an active algae situation that has not been eradicated fully and the high CYA limits my SLAM options. The fiberglass surface over the old plaster is very smooth and does not seem to allow the growth to get a purchase onto the sides or the bottom so it is easily brushed and the opaque balls (assume this is dead algae cells) is easily vacuumed up if careful not to stir it up too much.

I will drain the water do some brushing with chlorine as the pool gets low and inspect potential hiding places before I start the refill. I will take your advice regarding the fresh water balancing and attempt to keep my CYA to a manageable level. I need to be able to utilize a SLAM to keep ahead of the algae when it starts to get going.

I always enjoyed chemistry and used to have a set long before I had the classes at college so I do enjoy my Taylor K-2206.

 

[CJadamec]

If you are going to scrub the pool with some bleach and water when it is empty when you refill most of your algae will be gone. You will have some in your lines and filter but you will be way ahead of the game. Part of getting started for the SLAM is to get your pH to around 7.2 you will want to get that taken care of and adjust your TA to buffer pH changes. Another thing you should try to find out is if the water you are filling with is high in iron.

If all goes well your SLAM after the fill should not last very long.

 

[Oly]

Started the pool draining Friday at 10am and I expect the pool to be filled this morning Saturday by 10am, so far so good. Did not use an electric submersible pump but opted for the gas powered 2" pump and it pulled about 5,000 gallons per hour and I was drained after 6 hours.

Here are my first numbers with the water not quite to full:

FC 0.6
CC 0
pH 7.4
Ca Hard 100
TA 160
CYA less than 30 (none detected)


I am going to double check the TA and Ca hardness but if correct I will have to get my Calcium numbers up. The CYA levels were below the range to be tested by the Taylor kit as the mix of pool water and reagent did not cloud the water at all it seems. I did drain all but perhaps 300 gallons of the old water so I assume my CYA is very low now and I want to reach a target of 30 to start. I will be safe and assume my CYA is 10 and reduce the calculated required applications as I work to my goal.

I also cleaned the filter grids and sanitized all the areas of the pump, skimmer box and bottom drain. I brushed the walls as the pool drained but did not get aggressive with the sanitizers as I did not want to damage the fiberglass seal. I have learned that the plaster was coated with Fibre Seal seven years ago. I am happy with the condition of the surface after inspecting it during the draining process. I did not see any algae adhered to the pool surface and the top coat is in good shape and smooth throughout. I did not change the light, no time, no leaks and if it works......

So I will get the filter back together and have it running by the time the pool is full.

Any suggestions besides following the PoolMath Calculator at this point?

 

[CJadamec]

There is no CYA in municipal water so you should have 0. Pool math is the easiest way to figure out the dose of CYA to get 30ppm. If you are confident in the 30k number for size of your pool you can start dissolving the full 30ppm dose recommend by pool math it will take a day or 2 for the cya to fully dissolve. Chances are being in the strong sun all day you may end up wanted a CYA of 40-50 to manage FC loss from sunlight. 30 is a good starting point.

Other than that it looks like you have some great water to fill with and you should keep going with what you have planned. I think you are going to be shocked at just how easy it's going to be to take care of your pool after this. At some point in the near future you are going to be asking it can't be this easy I must be missing something.

 

[Oly]

Thanks CJadamec for hanging with me on this project and I look forward to being shocked to learn how easy pool care can really be. This site is a gold mine and I look forward to helping out as I get more experience and do intend to donate some of my savings to keeping this forum operating.

Using pool math I need to add just over 100oz of CYA that is 6 and 1/3 lbs to go from 5 to 30ppm for a pool of 30600 gallons. I will start with 5# in a sock in the skimmer and watch it after a few days.

To get my calcium hardness into the range it says I will need to add 34#s calcium chloride, seems like a lot. I may research that a bit more as the pool walls are coated with fiber glass with no exposed plaster. I do have grouted tiles.

Getting ready to fire up the pump now. Any reason why I can't use up a few extra bags of CaHypo 48% now while I am getting things dialed in?

 

[CJadamec]

The Cal hypo is fine read up on it in pool school and see what extra effects it will have on your water.
Remember to treat your water like it has a CYA of 30 while it is dissolving. Use pool math to figure out how much you need to get to about 4 FC.

When making large changes to TA, pH, and CH start with half the amount pool math recommends. See how you balance out with a half dose and go from there.

For CYA and FC pool math is pretty spot on for the amount you need to get where you are going.

 

[Oly]

The Cal hypo is fine read up on it in pool school and see what extra effects it will have on your water.
Remember to treat your water like it has a CYA of 30 while it is dissolving. Use pool math to figure out how much you need to get to about 4 FC.

When making large changes to TA, pH, and CH start with half the amount pool math recommends. See how you balance out with a half dose and go from there.

For CYA and FC pool math is pretty spot on for the amount you need to get where you are going.

 

[Oly]

Update, going good. The water is significantly clearer and actually feels different (nicer on the skin) than before. The temperature drop is a fantastic side benefit also but I expect that will not last long with air temps in the low 100s.

FC 5.7
CC <0.2
TA 160
CaH 130
CYA ? <30 (dissolved 2# yesterday will add another 2# today) Calculated need at slightly over 6# for 30ppm.

Adding CYA slowly now to reach 30ppm but still below. Is there a method to get a lower CYA reading than 30ppm with the Taylor K2006? The top of the site tube is 3-ppm and I would like a bit more resolution of the low numbers, I don't want to burn through my CYA reagent too fast and for sure do not want to get CYA too high to fast. I have been adding the dry CYA at amounts 1/3 the calculated and know it will be a couple of days for the full effect. I assume also I should see a FC drop during the day if my CYA is too low correct?

I brought my FC up last night to 6ppm and checked this morning and am at 5.7 with little to no CC 0-0.2ppm.

The Ca Hardness is still low at 130ppm and I am going to bring that up slowly as well to target 200ppm. Calculated amount is now 22# of CaCl.

TA was 160ppm out of the tap so not going to change that.

 

[CJadamec]

With CYA we don't really get any more specific than 10, 20, 30 ect. Unless your pool is indoors we don't really care about anything under 30. You will still probably want a CYA between 40-50 for the sun demand.

In general the only numbers we need single digits resolution for are FC and CC. All the other numbers we deal in rounded 10s. Remember it's the trouble free method we like to keep it as basic and simple as possible. You are getting closer to that "it can't be this easy" moment.

As for CH I would shy more towards the plaster scale to protect the plaster under the fiberglass.

It seems like you were blessed with beautiful fill water if you are already maintaining FC overnight there is no need to SLAM at this point.

 

[Oly]

And I thought I had clear water before this process. No more debris on the pool bottom each morning now. Good thing I did not cut down that tree thinking I was dealing with pollen.

Working up to my target CYA and CH levels and should be there in a few more days.

Keeping FC levels at 6-7 each night with 1 gal 10%. By morning I have lost 1ppm FC and after 24 hours my FC is at 3-4ppm. CC is always below 0.5ppm and pH at 7.4.

Zen and the Art of Pool Maintenance. Getting into the zone now.

 

[CJadamec]