Help trying to keep preventing a SLAM every few weeks

[tuxedy]

Clarifier isn't good for your filter and shouldn't be necessary. You can add a cup or so of DE to your sand filter after each backwash to increase your ability to filter smaller particles...enough to raise the filter pressure by 1 psi, no more.

I wish I could get DE powder, can't here in Rwanda.

Million dollar question still is, when the pool turned teal and partially cloudy with no apparent overnight chlorine loss, is that purely the result of a huge bather load and contaminants requiring the filter to work extra hard, or is it indicative that I have algae and need to slam?

 

[skimmerswimmer]

Usually a cloudy pool or color change is indicative of an algae bloom, which is contradicted by your lack of FC loss. So either the FC loss measurement was incorrect or something else is going on.

 

[mgtfp]

Green colour can also be a sign of metals in the pool. But usually water is more turning green then when FC and pH get high. In your case, a SLAM clears up the green, that doesn't fit with metals.

You might have some algae lurking in the pool somewhere, and FC is just controlling that. But after a pool party, or being away for a week with no chlorine top-up, the algae takes aver again.

Have a look at spots where algae can hide, like behind pool lights, skimmer weir door, pool cleaner, hoses, etc.

 

[kellyfair]

Another thing, be sure you aren’t backing off of a SLAM too early. And I think you said that when you were between SLAMs, you weren’t checking FC daily, and it got a bit low. I would check every day until you are consistently showing that your additions are keeping FC where it should be.

 

[tuxedy]

Is it enough that the kids leave water guns in the sun (big super soaker reservoir ones), that algae could be growing in those?

A bunch of kids that time had just come back from swimming in the lake 2 weeks before. I forgot to tell them to wash their clothes detergent prior. Perhaps that was enough to cause a bloom, but again, I am so surprised that my FC never dropped lower than 10ppm during that party and I had dosed up afterwards as well. Can algae still bloom when FC is kept in check with CYA?

 

[mgtfp]

Could that here be an option to get more reagents?

For the test kit, some other international members have had success using MyUS.com. They are a package forwarding company. No idea if it will work for you in the EU.

At least Rwanda appears in the list to calculate postage for.

 

[mgtfp]

Is it enough that the kids leave water guns in the sun (big super soaker reservoir ones), that algae could be growing in those?

A bunch of kids that time had just come back from swimming in the lake 2 weeks before. I forgot to tell them to wash their clothes detergent prior. Perhaps that was enough to cause a bloom, but again, I am so surprised that my FC never dropped lower than 10ppm during that party and I had dosed up afterwards as well. Can algae still bloom when FC is kept in check with CYA?

Theoretically yes. But if FC is high enough, then Algae should get killed pretty quickly.

Depending on water circulation there can be areas with locally lower chlorine where algae could grow even if the average chlorine level is high enough. But that leads usually to algae patches at the floor, walls, lights, etc, not to green bulk water.

Maybe you are overestimating your chlorine with the small sample volume that you have to use until your new supplies arrive. You might overestimate your FC by up to 4ppm. Maybe don't count the last drop that actually turns the sample clear, so that you rather under- than overestimate you r FC.

 

[tuxedy]

I've never seen algae on my pool, at least what appears to be mucky stuff, it's only been the tinge of green (and at one point a super deep tinge) - but the walls are usually okay, there may be sediment that even with a flick of motion of water it flushes off.

 

[kellyfair]

I've never seen algae on my pool, at least what appears to be mucky stuff, it's only been the tinge of green (and at one point a super deep tinge) - but the walls are usually okay, there may be sediment that even with a flick of motion of water it flushes off.

Technically you have indeed seen algae in your pool.

 

[mgtfp]

Just edited my post above: Wanted to say over-, not underestimate.

 

[mgtfp]

What doesn't fit is your chlorine demand. When as green as in post #18, it should have a very significant chlorine demand, but that doesn't seem to be the case. Maybe there is a copper problem, but here I would expect turning green more when you go up to slam level. Did you ever use algaecide? Some contain copper, which can create green tinges and even staining later down the road. Can you test your water for copper? Any chances of buying a kit or getting the water tested for metals somewhere?

It could be helpful to start logging water colour and cloudiness together with pH and FC. Maybe we'll see a correlation that makes sense when looking more systematically. You could use the PoolMath app to log your test results and add notes how the water looks like. PoolMath logs can be made visible to the forum members, which will make it easier to help you.

 

[tuxedy]

Pool is nice and blue, clear, I started last Thursday night. To be honest I was getting a bit inpatient and bumped the concentration to 38ppm for Mustard Algae (I did this once in the past and the color immediately changed in 8 hours) for one dosage, and then drifted back to 26ppm. Here's a photo from yesterday.



Now to be utterly honest, I can't test for OLCT accurately now as I don't have enough reagent until beginning of June when my precious visitor is coming with goodies from Amazon. I was testing a sample of 2.5ml with each drop equalling 2ppm. If I try testing 26ppm overnight loss with even a 5ml sample I will have used up almost all my remaining reagent. I decided to pump it up to my shock level and run the pump all night long again. This morning I tested 24ppm with no CC but that test can't really be tested. Just gonna have to wait and see how things do when I let them drift back down to manageable FC levels that I can test with what I have remaining.

I'm used to things running out all the time in Africa. One pool store. They were out of Acid for 2 months, and Cal Hypo for several months too. Just gotta learn to stock up - I do the same with Oreos and Cheese!

 

[tuxedy]

The color doesn't seem to correlate to pH levels. At one point of time 2.5 months ago the surrounding grass wasn't sloped properly away from the pool and we had issues of big rainfalls and runoff going back into the pool. That hasn't happened since. So the teal does go away with slamming the pool. But in the past it never lasted more than 3 weeks - but I've only had my reagents to test from the beginning of April (which I'm almost finished my titrating DPD drops!)

 

[tuxedy]

One other caveat - my pool has no lower drain. Just two returns on opposite corners and one skimmer. I suspect I don't have the greatest circulation. I've considered leaving the manual vacuum facing up in the deep end, but with frequent power cuts I dread the idea of the hose losing pressure and then floating to the top and when power kicks in I'm getting air into my pump.

 

[mgtfp]

So the teal does go away with slamming the pool

You're doing a pretty good job with the resources you have available. Let's hope that your supplies come in as planned.

Really doesn't sound like it's a metal problem when slamming clears it up - that would be a feast for metals, esp mustard slam level.

Best you can do until able to do an OCLT is to keep FC on the high side. I'd recommend to try to stay above target-FC after the mustard slam, that might help to maintain what you won with that slam.

 

[mgtfp]

One other caveat - my pool has no lower drain. Just two returns on opposite corners and one skimmer. I suspect I don't have the greatest circulation. I've considered leaving the manual vacuum facing up in the deep end, but with frequent power cuts I dread the idea of the hose losing pressure and then floating to the top and when power kicks in I'm getting air into my pump.

I also don't have a lower drain (or main drain), but I have a suction side cleaner. Even though robots tend to do a better job cleaning, I quite like the fact that my cleaner helps to mix the water layers, esp in winter when the pool stays open but doesn't get used.

Mixing the water is also a nice side effect of brushing and of trying to get every single leave with the net - great tea spoons.

Once you have enough reagent, you could take a few samples around the pool and test FC. That will show how good the circulation is.

 

[tuxedy]

The benefit of living in Rwanda is cheap labor, so I have my guard brush the pool daily and vacuum every other day. He even adds my 4ppm every two days (predissolve and walk around). But when I start pulling out my test kits and titrating all is lost in translation

 

[mguzzy]

I've been following this and wanted to chime in.. It sounds like you are following the FC/CYA Levels as best you can and you understand how that works. And using smaller sample sizes is a great way to save reagents. Especially if the higher precision isn't needed. And you continually pass your OCLT test. But the thing that stuck out was you said you raised your CL and the cloudiness went away after 8 hrs. or shorter hmmm. I wonder if there is something else going on chemically. And that cloudiness you are seeing isn't algae but a precipitate of something else that is going in and out of solution as the water conditions change. @JoyfulNoise whaddya think? If you are chlorinating with exclusively with CalHypo I'm surprised your CA is only 225. The other thing is your water looks very similar to natural water sources that have high CA.. Like Pamukkale or Agua Azul.

 

[tuxedy]

In terms of continually passing OCLT test, I wouldn't be 100% on that. Until I get more reagent I will assume that it has in the past but not since my most recent SLAM.

It was the color that changed dramatically after adding the mustard algae level (I had the pool at 3 days of regular slam level). The clarity took 48-72 hours to improve after that addition.

Our water here is super soft. 50ppm coming from the tap. Also barely any alkalinity and pretty basic (>8). When I filled my pool it was clear light green - someone posted about how that is likely from CCs in the tap water.

So we chlorinated with CalHypo 65 granular since we installed the pool Jan 2021. I added stabilizer but it never showed up in my strips so I was chlorinating like 1ppm day, if anything. SLAM/shocked 3x since January, of which one time I used trichlor to do so and really regretted it.

Since the pool is painted CH should be kept really low?

I have kids so splash out happens quite a bit, it's rainy season so getting some dilution and I was backwashing every 10 days before that. So that's possibly why CH has kept low.

 

[tuxedy]

So an update.

Pool has never been this clear for so long. After doing my CYA levels testing several times I'm in the ballpark of 65CYA, which means 8-10FC ideal. I've been adding 4ppm of Cal Hypo granular dissolved every other night. It usually is either at 10ppm or 11ppm when I add it, so my usual Chlorine consumption per day is about 1.5-2.5ppm per day. I've also noticed that it hasn't made a huge difference if its super sunny or cloudy or sometimes raining. If kids are swimming less than an hour there isn't much change to that either. I have been testing only once per week now. Interestingly, after all my shocking with Cal Hypo, the CH is still at 225. We've received quite a bit of rain and draining out of pool a bit, but not oodles. Regardless I guess I'm lucky that my water refilling sources are so soft.

Another interesting change I've done. I searched on the forum here about pump time needed. My filter is about 10,000L/hr, and my pump is slightly overpowered but that would mean I would need 6 hrs of pump time to run my water through 1x a day. I've done that for the last 5 months of ownership, but since I don't have a SWG, I've reduced it to 3 hours only. 1 hour during the day to mix things up then 2 hours at night when I add my chemicals. I am tempted to reduce down to 2 hours. I've not noticed at all any change in clarity.

I use a solar cover that covers 1/3 of the pool only, but since our high temps here average 24 degrees these last few months my problem is primarily the pool being too cold. Averages about 72 I think. (22 C?) When the pump was on more the pool was definitely warmer throughout. Now I feel the top layer being warm and everything else frigid.

Thanks everyone for their advise during this time! I will be getting a 16oz titrating dpd fas liquid in 2 weeks so I don't need to skimp much more on my testing!