Help trying to keep preventing a SLAM every few weeks

tuxedy

Well-known member
Jan 16, 2021
50
Rwanda
Hello everyone, new here. Been following TFP very closely and recently got my Taylor K2006 kit.

My pool is a 15000 gallon new concrete pool (since Jan 2021) with acrylic paint. I run a 0.6kw pump 6 hours a day, which in technicality filters my water 1x through my sand filter.

Recent readings:
CH: 225
TA: 70
CYA: 65-70?
pH: 7.5
FC: 10ppm
CC: 0.5ppm

I've had a lot of problems in the past few months with algae and cloudiness, mainly because I added CYA as a conditioner first by itself and my test strips were not registering it. I continued to use granulated 90 trichlor for a while, even to shock based on the store's advice, and that led to my CYA level higher than I would like it. But the sun, when it is out is very intense, UV is usually registering at a level of 12.

Test strips were all I had before I got my Taylor test kit a month ago. Also I live in Rwanda so the abundance of chemicals and test kits are difficult, I depend on people bringing them over here for me.

Most recently, about 3 weeks ago I thought I nailed it with getting my pool under control. I kept the pool at 38ppm with Cal Hypo 65 (it's all I have) to maintain Mustard Algae SLAM level, and did manage to get OLCD of 0 and 0 combined chlorine. I allowed the pool to drift to about 21ppm before letting people swim. It was clear as day, light blue as day as well. I started measuring daily loss, which would be 2ppm on a very sunny day with no pool cover, and 1-1.5 on a cloudy day with little to no activity.

I use Cal Hypo on a regular basis, adding 4ppm every two days and keeping my pool above the recommended range of 8-10ppm for my CYA level.

We had the largest pool party so far, 4 men, 11 kids, from a staggered period of 10am to 4pm, full sun. The pool was at 12ppm, CC 0 before the party began, and then it dropped to 10ppm. CC 0.5ppm after the party. I dosed up 12ppm at 5pm and by 9pm it was back down to 10ppm again. Next morning it was like 9.5ppm. But I noticed already after the party that the pool was cloudy (expected from so many kids and sunscreen) but it was changing to that slightly teal color, which gives me trauma that it would sometimes get out of control. I don't want to pump it up to shock level of 28ppm unnecessarily. I've had the pump running all night and day so far, the cloudiness has improved some (which isn't too bad, I can see the deep end, it just isn't as sparkly and crystal clear as I was getting it to become).

My questions are:
1) After a pool party, I've read that cloudiness takes a few days for the filter (sand takes longer) to get rid of the organics. However, the slight tinge color change, is that expected? I've brushed and vacuumed today (and we backwashed the filter before the party). Does it mean I need to SLAM again when there seemed to be a low overnight loss? The color literally changed in the last hour of the pool party but the chlorine never dropped below 10 to my knowledge.

2) Is daily chlorine loss a percentage or fixed amount per day? Meaning, at a higher amount of 21ppm, it was dropping 2ppm on a sunny day. Would I expect that if it were at 10ppm it would also drop an equal 2ppm or more of a ratio of the FC? (like 2ppm is 10% of 20ppm, and 1ppm would also be 10% of 10ppm?) To keep pool maintenance easy, would I be safe to add 3 days of chlorine (6ppm) every 3 days? Should I expect chlorine consumption to be

Thanks guys! Trying to keep on top of this!

BTW: Cal Hypo has been working well, we usually dissolve it and then walk it around the pool for daily chlorination (or every 2 days). Also with the CYA level, given our high UV I am okay with maintaining a higher FC level, I just don't like the idea of putting in so much chlorine when we have a problem! Also, our water here is super soft, 50ppm hardness so the Cal Hypo works wondrously in our context.

Thanks!
 
How sure are you of your CYA level? Could it be higher than you think? Also, when you last slammed, did you brush/clean out all the hiding spots of potential algae (like ladders, behind light, etc.)? To prevent algae, you need to make sure you never fall below the minimum FC level on the FC/CYA table, but you absolutely have to have an accurate and repeatable CYA number first. You should probably be adding chlorine every day until you have this figured out.
 
tested CYA level several times. I know it is within range because I added about 40ppm or so with dissolvable conditioner and then about 4kg of chlorine 90 over several weeks, which with my calculations brings me to about 37ppm. That brings the total possible CYA to be about 77. But with splashout, backwashing and rain, I wouldn't be surprised it dropped back down to 70. Tested twice with the dot test 1 week apart, and practiced several times the second time and found it was about 65-70.

I have no ladders, but honestly our pool paint was done very poorly by my contractor (done over several days, with a rain in between and then the guy painted the last coat in the middle of the heat direct sun) so its bubbling everywhere. Like EVERYWHERE. Some places the bubbles have popped a bit and perhaps algae is hiding there but there's nothing short of draining the whole pool and painting again- my contractor said he would do it for free, but then again he hasn't replied to any of my calls or texts since finishing ...

But these bubbles do make it hard to brush well, sometimes I feel like I'm rubbing off the bubbles and getting streaky marks of the concrete underneath. So perhaps the algae is hiding in those places.

Would one expect the color to change even though there has been no OCLT and religiously keeping on top of the recommended FC / CYA levels after bather load?
 
You can run your pump a little longer and bump up the chlorine a little higher on days when the pool will see more use. When you see a little cloudiness, that is the first visual indication that the chlorine demand is getting away from you. I used to have a sand filter prior to getting my DE filter and I remember the water took a long time to get clear after opening each season. I also run my pump 12 hours per day, but it is a variable speed model so a lot cheaper on electricity. There may be issues with the paint and bubbles, but I don't have any experience with painted pools. Hopefully someone comes along with some additional info and suggestions for you.
 
Appreciate the advice. The color is kinda coming back to being blue again, I dosed according to my usual schedule. The clarity is improving slightly 2 days later but kept pump usage on day 2 to normal.

Does anyone know if FC loss is a percentage or fixed amount per day? Like my previous example of the pool being at 20ppm and losing 2ppm per day or at 10ppm and also losing 2ppm per day?
 
FC-loss due to UV is is a percentage of the FC-level.

If you have organics in the pool, then they will just keep consuming chlorine, until either the organics are all gone, or no FC left. At higher FC, this process will be faster.

Your 2ppm loss at 20ppm FC and CYA 70 sounds nearly too good for being practically at the equator. Are you sure about these numbers? Do you get a lot of shade on your pool, or do you have a cover?
 
Just thought about your numbers a bit more. Here in Melbourne, the UV-index goes up to about 11 in summer. On a sunny day, I loose about 2ppm (maybe a tiny bit less, hard to tell within the test resolution) of chlorine per day while maintaining FC around 9ppm with CYA 80ppm (i.e. about 20% loss of my FC-level per day). Your UV-index seems to be a bit higher (12, you say). On the other hand, your daylight hours are shorter, around 12h that close to the equator. In Melbourne, we get nearly 15h around Christmas, that probably compensates to a certain degree for the slightly lower UV-index. So, around 2ppm loss at an FC-level around 10ppm probably sounds reasonable, But I would expect about double of that at FC 20ppm.

10% loss per day sounds very optimistic, unless you have shade on your pool for big chunks of the day.

But I might be completely wrong in my thinking. Would be great to see more testing data on this, very curious...
 
Mind you, I've only had my pool for a few months and recently been testing this last month only.

Daylight hours are very consistent, 6am-6pm. Sun when out is intense, but we are in a "rainy season" with a chance of rain daily, though that doesn't always happen. Summer here is very dry, barely rains for 2-3 months. That will be the ultimate test to see what the FC loss is. I use a cover but that was a cover given to us from an above ground pool, it barely covers 1/3 of the pool. It receives full sun in the morning until 3pm when the pool gets a bit of shade from our 1 story, but I would say that 2/3 of the pool is in full sunlight all day.

Noticed that if it's sunny and minimal swimming, I was getting 2ppm at that high level per day loss. Partly cloudy or a little rain maybe like 1.5ppm.

Recently after our big pool party, I dosed up to 12ppm, and 2 days later it was down to 6ppm , cc is 0.5, (3 loss per day with no swimming, 50% sun during the day) - I was surprised, perhaps it was because it was still trying to fight stuff off in the pool from Saturday the 24th. I dosed back up to 12ppm tonight, going to do a OLCT test tonight and see if the pool has organics or algae it is still fighting that would cause the recent increase of daily consumption.

Again, I would love to resist doing a SLAM if it just takes time for the pool to "rebalance" after a big party like that. I know about Algae needing to be slam'ed to be removed, but what about all the organics of human skin, saliva, sunscreen?
 
Normally, you don't need to slam after a pool party. FC in target range will take care of the bather load, low level of CC should disappear quickly. You can speed things up by increasing FC a bit higher. But if you leave FC too low for too long after a heavy bather load, that can turn into an algae problem.

You can increase FC a bit above target before a pool party. Anything up to SLAM-FC is safe to swim in.

OCLT is always a good idea when you are unsure.
 
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Even covering just 2/3 of the pool will safe a lot of chlorine.

Just keep track for a while, write down your FC levels, how much you add, weather conditions (if you have an internet source for the current UV-index, then you could use that), bather load, cover on or off, CYA level. After a while you will get a feeling for what to expect.
 

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So I have a question here. If I am maintaining my FC always to the proper FC/CYA ratio, why would my pool turn teal and slightly cloudy?

I've been following my pool 1 week post big party. I've kept my chlorine levels nice and high (8-12ppm) and never letting it dip lower than 8ppm (70cya). After the party it still hasn't cleared up, as it literally was turning this teal color and slightly cloudy. I've run the pump longer than usual (18 hours on the first and second day after) and still no improvement. Overnight loss was 0, and small amount of CC. Is the only thing I can do at this point is to SLAM the pool again? I just cringe at raising the pool to 28ppm at my CYA level unnecessarily.
 
Hey tux !!! After a party you raise the FC a bit to account for leftover bather organics. Then the filter needs to filter. There are no 2 ways about it. I stink at metric conversions but sand filters generally take longer to clear stuffs and a small sand filter takes even longer (if yours is).

You can get a lot of the floating body/suntan oils and sweat before they hit the filter with a couple of tennis balls in each skimmer. They are amazing at sucking stuff up. The added bonus is the kids will find them like a treasure, play with them a bit and they’ll float right back in the skimmer once the novelty wears off.
 
Have you cleaned out your filter recently and added some DE to the sand filter to catch the smaller stuff? If you're not losing a lot of FC and your CCs are low, it could just be a filtration problem...or you could have algae hiding behind a light or inside ladders, etc. Make sure you're brushing the walls and floor as well...every day until it clears up. This will help get any residual contaminants into the filter. There is also no harm raising your FC to SLAM levels unless you are swimming.
 
Being in Rwanda, I don't have access to DE Powder. But I slammed it anyways today to 26 ppm (CYA of 65)- I'm also running really low on reagent, someone is bringing some for me in June from the states. I've had to try to use 1.25ml - making each drop register 4ppm. I know it's inaccurate but it's giving me ball park measurements. I am more concerned that the teal goes away, as last time this happened we lost control of the pool.

That is the magic question. I haven't noticed much chlorine consumption, making me wonder if there truly is algae, but today the clarity was getting worse. Mind you I can still see the deep end, but it's hazy - (I have all these bubbles in my paint, and when it is slightly cloudy my pool paint looks great!). If the pool starts to get cloudy, does it usually start turning teal? I was considering using flocculant today to get the Crud to the bottom and be done with it instead of slamming

What an idea on tennis balls. Does that soak up all the oils and then you wash them separately?
 
Are you sure the cloudiness is not the paint disintegrating? Pool paint does not last long.
 
I doubt it. Other than the small bubbles that occasionally rub off, it's not becoming sediment.

Is Teal color always a sign of algae? I doubt I have phosphates in the water, I can't test for them unfortunately.

Here are some pictures of where I've been with my pool. I am still a brand new pool owner - 5 months only.
IMG_1374.JPG
This was the pool at it's worst - March 22
I slammed this thing to the best of my ability without a test kit at the time for mustard algae - my test strips didn't show any CYA and I made the mistake as per local pool store to use trichlor to do so.


IMG_1380.JPG
March 23 - color change was great but cloudy, continued to run pump 24h brushing etc

IMG_1386.JPG
March 26th, clarity improving dramatically, still no idea what the chlorine levels were as didn't have good kit. But this clarity and color are what I try to shoot for. Best judge of "blueness" is in relation to the pool cover.

We left for a week trip and when we came back it started turning teal color again and slightly cloudy.

63992674170__083C85C0-C3C4-4A5F-B6C7-22E8916CC5FB.JPG
This is when I got my Taylor test kit and was able to determine all my CYA levels and FC levels. Slammed the pool to mustard algae again, 38ppm. It dropped to 30ppm over night, added 8ppm in the morning, and the color instantly improved and clarity by that afternoon, but it dropped to 21ppm. I didn't bump it back up to 38ppm, but noticed the water being super clear and no OLCT with no CC. That is when I allowed it to drop back down to normal- it kept super clear and clean, with 1.5-2ppm loss per day.

IMG_1542.JPG

This is the clearest and nicest our pool had ever been, in the shallow end while underwater you could see clearly the deep end when someone dove underwater.

IMG_1624.JPG
Teal and cloudy again after the huge pool party we had last weekend. This photo is from this morning after I began slamming at normal slam levels - 26-28ppm. I've maintained 28ppm (just started yesterday at 5pm) - it lost about 2ppm overnight.

Am I doing everything properly?
 

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