Turing a big green monster into a blue pearl

[Lombaardcj]

Hi Everyone,

I'm a first-time pool owner but grew up helping my dad with pool maintenance and house sitting neighboring swimming pools in vacation time.

It did not prepare me for my current challenge. I took ownership about 6weeks ago of a pool after moving into new house and I'm desperate for advice on what to do next.

Tried for three weeks to clear pool of green algae with no apparent effect. Water condition is a cloudy bright green color at the moment. Can't see my hand when I take a water sample. It all got worse after several days of heavy rain and thunder three weeks ago. The water clarity before the rain started was already cloudy with algae present.

This afternoons water sample test at the local pool maintenance shop shows:
FC - 0.9 ppm
TC - 1.2 ppm
PH - 6.9
TA - 80
CH - 550
CYA - 55

FC, PH and TA corresponds to my home test kit results

I've tried to shock the pool with 4x maintenance dose of chlorine (5kgs over three days) with two bottles of algaecide treatment after reading the SLAM article through a few times, but I've run out of dichlor and left with cal-hypo. Started shock on Saturday morning.

After seeing no improvement in the color of the water or the clarity improving, I finally opened the sand filter to inspect this afternoon to find that it is very dirty with leaves trapped into layers. There is no calcification present. The previous owner replaced sand 14months ago. The leaves are spine shaped from a nearby tree and seem to have passed right through the filter baskets unhindered due to the size and shape of the needle-like leave.

The pool cleaner and pool skimmer are in good working condition. No floating debris in the pool water or on the floor of the pool, fortunately.

Question time:
1) Should I try cleaning the filter sand by washing it or rather replacing it?
2) The pool agent suggested I try using Peroxide after the current FC & TC goes to zero to "try" and kill the algae. Is this a waste of money exercise if I've already tried such a high shock treatment?

Kind Regards,
Chris


My Pool
19K Gal (75K ltr), IG(20+years old), Plaster, 1hp motor, 350lb Sand filter, 1 Skimmer, 2 return jets. No filter pressure guage.
Filled from borehole and rainwater.

 

[Texas Splash]

Hello again Chris! In your intro thread you stated that there was no presence of iron/copper, however I believe you mentioned that some algaecides were used in the past correct? Algae will turn a pool green or even close to black in color if it sits too long. But when someone describes their pool as bright green, I still wonder about metals. Any chance you could post a pic for us?

I don't see a need to do much with the sand - yet. Perhaps a good deep cleaning may be in order as seen on the TFP Deep Cleaning a Sand Filter page, but that in itself won't remedy algae. The SLAM will do that. But remember these key facts for the SLAM:
1 - You MUST have a test kit that will allow you to verify your current CYA and be able to test FC over 10ppm, in many case upwards to 20-30ppm of FC. The FC testing will need to be performed frequently each day to ensure the proper SLAM FC level is maintained.
2 - If you do have some iron/copper in the water, an elevated Free Chlorine (FC) level may aggravate the metals and cause the color to get brighter or even try to stain the pool surfaces. It's just something to be aware of.
3 - You'll need to find a good source for chlorine locally. A SLAM can take several days to even a week or two to complete when done properly. There simply is no magic 1-2 day formula. Chlorine (aka bleach, sodium hypochlorite) is the best remedy for algae.

If we were to accept the pool store results above, which we are hesitant to do, your pH is a bit low and should be closer to 7.2 to perform the SLAM. Aeration should help with that if you have a fountain or way to stir-up the water. If your CYA truly is 55, we round-up to 60 making your SLAM FC level a "24". This is why the proper test kit is so important. I'd slow down on the cal-hypo as your CH is starting to get elevated.

I'm sure more replies will follow. Lots to grasp at first, but let us know as you continue and have questions.

 

[Lombaardcj]

Hi Texas Splash (Like the handle),


I've attached a photo or two to show the water condition as well as the filter sand.


That is a lot to take in so I'm breaking it down:

1. I do have a home test kit but it only goes up to 3ppm on Total Chlorine. Getting hold of a test kit that can be delivered to me in ZA is difficult and seem to work out very costly due to the exchange rate to my local currency from USD. I know from reading the SLAM article that this is a must, but it could take months before I can test chlorine accurately above 10ppm? So what is my alternative?
2. I've stopped any chemical treatment except for adding Alkalinity until I know I'm prepared to do a proper SLAM and finding the right chlorine and enough of it.
   1. What type of Chlorine should I be shopping for if using Cal-Hypo will increase the hardness? Should I buy Di-Chlor or look for an alternative3)
3. I have just completed deep cleaning the filter sand by removing it completely and washing out the organic debris as far as possible before returning it to the filter unit. From the video on the TFP Deep cleaning article, my sand looks okeyish.
4. Considering the CYA level at 60 and Hardness of the water over 550ppm, should I not consider replacing some of the water. If this is an option, can I use a floculant to get rid of algae suspended in the water to the bottom and vacuum it out. I've got the hoses and vacuum extension to do this. I have the option to refill from municipal water instead of borehole to avoid calcium hardness problem.
   1. I want to CYA to lower to between 30-40
5. I checked the active ingredient used in the algaecide and the chemical compound is Didecyl Dimethylammonium Chloride (C₂₂H₄₈ClN). No heavy metals information provided on packaging,
6. I wanted to know in my first post if Peroxide could be used as an alternative option to chlorination?

Thanks for the guidance. I wanted a blue pool for Christmas day, but that seems to be all but a dream now considering no one can swim if chorine is above 3ppm.

The below chart in taken from the other article is very good guideline thank you.

Non-SWCG Pools

 

[Texas Splash]

Okay, a few responses to your latest questions:
- For a test kit perhaps ether this one: Kits Clear Choice Labs or this one: Taylor FAS DPD Test Kit Chlorine - SERVICE SIZE K-2006C $144.99
may work for you? The Taylor K-2006C kit is what you want over there. They will test FC as high as you need it.
- Stick to pure (regular) bleach, chlorine, liquid shock. The main ingredient is Sodium Hypochlorite. Stay away from dichlor as it will increase your CYA, and cal-hypo will increase your CH - neither of which you need at the moment.
- Definitely don't use any floc at this time as it could gum-up your filter and make a mess of things if allowed to get there. With your sand filter, you probably have a multiport valve for backwashing to waste which is what you would do with floc, but still, not needed at this time.
- That tint in the water seems a bit bright to me - more than just algae. Probably copper from algaecides or other pool store products. For that reason, I would recommend a water exchange. As much as you can do at a time without leaving the plaster totally exposed for too long, and never go lower than 1 foot or below the lowest step. Once you refill, you will have removed much of the metals, lowered your CYA and CH, and will be in a good position to start a SLAM at and (hopefully) an ideal CYA of about 30.
- Peroxide has been known to reduce excessive chlorine levels, but that's not an issue for you, so I wouldn't try to use it. Your biggest advocate right now will be regular bleach/chlorine once you complete the water exchange.

 

[kimkats]

First off want to tell you I love, love, love your pool and area! So pretty! Once this is over I would love to see more details of that wall at the far end. Looks neat.

Okay lets see if we can get you a test kit. Please give these folks a call:

Kits Clear Choice Labs

Next up is the chlorine aka bleach..........from now on you will only be using LIQUID chlorine (bleach). They are the same thing. The only difference is the %. Yes the bleach you use in your home to clean with. Just make sure it is does not have extra stuff in it like pretty smells or low splash.

Peroxide is a big nope it will do NOTHING to clear your pool.

Bore water---if that is what I would call well water in my area there is a chance it does have metal of some sort in it due to it's nature. Is there ANY pool water testers in your area? If so you could get them to test the water for metals. If you do have metal from the bore water we will go from there.

Don't do anything until Pat checks back in. He has lead you very well so far.

Kim

 

[Lombaardcj]

@Pat, Thanks,

I'm going to start the water exchange now and keep to the recommendation of not going too low. Read the articles and risks with groundwater and exposure to air.

Posted a question on the availability of test kits in my area. Unfortunately, I'll need to make due with what I currently have access to.

-Not going to use Peroxide.
- Need to find a supplier of regular bleach/chlorine. All the shops have Cal-Hypo in stock. They do stock bleach, but for domestic in-door use only in 500ml bottles.

@Kim,
Thanks for the referrals. Most places are closing down this time of year for annual holiday break. The best advice I can find at the moment is from you guys.

Your mention about the well water I think might have triggered a lot of problems thinking back to where I started 6weeks ago after moving in. Will avoid it for now.

 

[Texas Splash]

They do stock bleach, but for domestic in-door use only in 500ml bottles.

Take a look at those. As long as they are regular bleach (not scented or splashless - just regular), and the main ingredient is sodium hypochlorite, you can use it. I use regular bleach from the grocery store in my pool.

 

[Lombaardcj]

Thanks a million! Will rade the grocery store on the weekend. .

Got about 3'' of water out so far. Will post back once the refill starts with new water.

 

[Lombaardcj]

Update:

Ph 7.8
TC 0
Alkalinity 70

Can't test any other numbers like CYA. Pool shop closed until new year.

1) Replaced 30% of the water with tap water. No more borehole water until I know what's in it

2) Deep cleaned sand filter
3) Sucked out algae on the bottom while draining the pool yesterday and this morning
4) Took a good part of the afternoon to refill 22.5Kl or 31%

5) Water condition still green but less cloudy (Probably because the pump was not circulating)

6) Water was foaming slightly before water replacement with algaecide chemical smell. This is now gone

What's my next step? Get the Alkalinity up and the Ph down?

Then get liquid chlorine to prep for SLAM?

Any other advice?

 

[kimkats]

Take the PH down ot 7.2. The TA is fine where it is for right now.

It is going be hard without knowing your CYA but at least it is lower than before. Keep working on getting a good test kit. Until then.....get some chlorine/bleach. You cart should look like this:

I would pretend your CYA is 30 for right now. Your FC is going to be 0 right now is my guess. Use this chart:

Pool School - Chlorine / CYA Chart

Then this neat tool:

PoolMath

to see how much FC to add to get your pool up to SLAM level. Now comes the almost impossible part...........you have no way to know how high your FC is because your test only goes to 5. I GUESS you could add plain water to your pool water then double what the FC test you have says to see where your FC is at. This is NOT the proper way to do it but might be better than nothing while we wait for a good test kit.

Try to add FC at least 4 times a day. Take a pic looking down at the steps at least once a day to we can see what it happening.

Kim

 

[Lombaardcj]

Hi Kim,

Thanks for the suggestion to start buying. The local bleach brand says on the packaging 3.5% m/v - Sodium Hypoclorite and Aqua. Does this mean 3.5% weight percentage referring to the Poolmath calculator. I don't want to make a mistake here.

When I punch in the numbers the calculator suggests 25litres to go from 0 to 12FC. How do I know how much I need to maintain it once I start with the SLAM?

Numbers from calc:
Size 72500liters

Measure	Now	Goal	Recommendation
FC	0	12	Add 25l 0f 3.5% or add 1.5kg of di-chlor or add 1.35kg of cal-hypo 65%

I'm trying to attach a before and after water replacement side by side photo of today vs 2days ago. Looks much the same. How can I attach more photos? Attachment manager says I reach my quota and it does not seem I can remove the old attachments.

 

[Texas Splash]

the packaging 3.5% m/v - Sodium Hypochlorite and Aqua. Does this mean 3.5% weight percentage referring to the Poolmath calculator.

Yes. Whatever % is listed on your bleach containers, that's what you will enter manually in the "WEIGHT" field.

How do I know how much I need to maintain it once I start with the SLAM?

You will simply change your "NOW" number. At first, the NOW number will be zero, but later today it may be "6", so the calculator will know to adjust the bleach results based on a NOW number (6) to a GOAL number of (12).

So stick to just bleach and avoid any other chlorine products if you can. Bleach (regular bleach) contains just chlorine, water, and small amounts of sodium which are fine for the water. Good luck!

 

[setsailsoon]

Lombaard,

I did a little searching and there's a company called NCP Chlorchem that is a chlor alkali producer with a plant in S Africa. They manufacture 15% liquid chlorine but appear to sell in commercial quantities, probably to local manufacturers of cleaning products and mining companies for their waste treatment. You may want to contact Chlorchem (27-11-921-3111) to see if they will give you contact information of a local distributor or other customer that will sell you reasonable quantities. Could be a good long-term supply for you.

I hope this helps.

Chris

 

[kimkats]

PIctures-you can become a supporting member CLICK HERE to Become a TroubleFreePool.com Supporter!! This will help us keep the lights on and it gives you more pic storage. You can also try to use an outside pic hosting. Do NOT use photo bucket as they have started charging for it We are worried the others will follow suit.

Kim

 

[Lombaardcj]

Got the chlorine today.

So I'm ready to SLAM. I've adjusted the PH to 7.2 and retested now just after sunset to make sure.

TA 60
PH 7.2
CYA 30 (Approx based on pool math calculator and replacing 33% water)

I'll pour in 25liters 3% m/v now and retest in the morning and let the pump run 24/7. Filter is backwashed. The only thing I dont know is how much I'll need to add after first 12hrs because I cant test over 3ppm at the moment.

I'll sweep the sides and the bottom 2-3times a day and backwash once a day.

 

[mknauss]

Unless you can get a test kit to measure CYA and FC above 10 ppm, a SLAM is really difficult to do without a large waste of resources and time. There is no way to get a better test kit?

You can give it a try. But unless you keep your FC elevated to at or above shock level, this can take a very long time to be successful.

Good luck.

 

[Lombaardcj]

So: In the middle of hyper chlorination.

Started 24hrs ago with 25l at 8h30pm
Followed up with 15l this morning at 11:30am.

Then again 6liters at 16:30 this afternoon.

Ph now at 7.4

Noted that no chlorine at 11:30 this morning.

Then at 16:30 their was high free chlorine which tells me that it is starting to work right?

Keeping on with brushing.

Watching a few YouTube videos the water in almost all examples goes from dark green to light green to Grey/white cloudy to clear blue.

I'm not yet seeing a colour change but this is expected because the chlorine has to first kill off algae which takes time.

Some pics of what the pool looks like now and last night when I started:
https://drive.google.com/folderview?id=1Y9y6FBhQEW8doGn39F83dPwKfInG1ZSd

 

[Texas Splash]

If you are able to accurately test FC (free Chlorine) at the proper SLAM level based on your current CYA, and the FC is holding (not total chlorine - only FC), then that is a good thing. But I'm still concerned about the tint of the water. As I mentioned above, if there is too much copper/iron in the water, no amount of chlorine will make that go away. It will only make the metals more green, brown, and/or possibly cause staining, so keep a watchful eye on that. Do your best to monitor the FC level to keep it consistent at the SLAM level for best success against any algae. Once you pass all 3 SLAM criteria, then you can address the best way forward to manage copper/iron in the water. Also, assuming you lowered the pH to about 7.2 before starting the SLAM and increasing FC, the higher FC level will cause your pH to look higher. No need to test pH during the SLAM.

Hope that helps.

 

[Lombaardcj]

Thank you. Tested the FC this morning and it's at 0.5. So adding back 25l.

We had two big thunder storms the past two nights.

Is their more information on if and why this could affect the FC.

Not ideal during SLAM I guess

 

[kimkats]

Rain events have almost not bearing on a SLAM. Get and keep the FC up to SLAM level is the number one priority.