Quick SLAM done - Thank you guys!

[RicardS]

Hi all,

I had a rough introduction to algae last year and that's when I discovered TFP and the SLAM method. It took me a bit to get the hang of it, but I managed to get my pool water back to crystal clear again.

I've been maintaining my pool clean all through the fall, winter and spring with no problems but in the past few weeks I've noticed that I'm getting an algae blossom once again. I had been noticing that the water was not totally clear for the last few days so I did a complete test.

My levels on Friday were:


So a high FC level but on target with my 100 CYA. (I don't know why it went from 50 last summer to 100 this summer when I've only been using chlorine pucks.)

On Friday evening the water was even more cloudy:



And you could even see a film of "dust" on the surface:



I skimmed it with a white cloth to see what it was and:



And once the filtration started working I could see on the skimmers the dreaded green muck



So with no time to loose, I started the SLAM process before the situation escalated and I brought my chlorine level to 39 and filtration 24/7.

Water looked much, much better on Saturday and on Sunday it looked like this:



Yes, there's water in the pool

I stopped adding bleach on Sunday evening and I hope this killed the algae. I know I should run a overnight test to see if I'm losing chlorine, but I ran out reagents for my Taylor K-2006 on Sunday morning and I need to get replacements. (Reagents vanish when you have to get to FC 39!) But I think I comply with the other two conditions of the test, right? I can see the bottom and the water looks clear

So I want to thank everybody for all the knowledge shared in this forums that has helped me to do such a quick turnaround for as little as $15 in bleach.

Next steps will be to adjust PH levels, but my question is: what's the chlorine level I should get for the PH test to be reliable? And then I will need to lower my CYA level, but I'm going to need the reagents first.

Any more tips?

Greetings from Barcelona!

 

[setsailsoon]

Ricard,

Glad to see you have made this improvement even at such high CYA levels but I'm afraid you missed an important point. The high CYA is coming from the pucks. They are about 50% CYA and the CYA persists for a long time. You will continue to build up CYA if you keep using them. This is why we recommend using liquid chlorine or bleach for disinfection and not pucks. You should stay in the 30-50 ppm CYA range. 100 CYA is not recommended because it will require very high chlorine levels for effective disinfection. Also, the limit of the test is 100 so your level could actually be much higher. Please dilute the sample water with half tap water and run the test again. Then double the result. Don't be surprised if the test result is actually much higher than 100 so you may have to replace over half your water to get within the recommended range. Also don't waste chemicals attempting to adjust pH at these high chlorine levels. FC above 10 makes the pH test inaccurate.

I wish I had better news for you and hope you are able to correct the CYA level soon.

Chris

 

[kimkats]

I've only been using chlorine pucks.

Just like Chris @setsailsoon said this is where your CYA is coming from. The best thing you can do is use pool math PoolMath to see how much water you need to remove and replace to get to a CYA of 50 to start with.

While you are doing that look around your area for the best and easiest place to get the liquid chlorine and use that ONLY! Now you can use the pucks for overnight trips and such but when you get back take the un used part out and let it dry out until next time.

Now if you want an easier way to add chlorine you need to look into a SWG as seen here: SWG How It Works - Further Reading Talk about making your pool truly Trouble Free!

Kim

 

[RicardS]

Thank you for your replies.

I know, I know. I'm well aware that I have to lower my CYA level to a reasonable figure. I just need to make go until I have the refills. I'm just surprised that the pucks added so much CYA during the winter. The only solution is to drain part of the pool and refill with fresh water. I don't think that the Pool Math app calculates the exact amount of water to be replaced, but it seems only logical that to go from 100 to 50, I would need to replace half of the water.

 

[setsailsoon]

Ricard,

That could be correct. Or that could be not enough water. I would perform the CYA dilution so you know exactly how much before you start. What is the volume of your pool and how many pucks to you use?

Chris

 

[RicardS]

Chris,
The volume of the pool is 44,000 litres and I use two pucks, one in each skimmer. They last a lot in the winter and probably about a week now.

I’m planning to go and pick cya reagent today and see where we are now since I did vacuum to drain and refill a couple of times.

 

[setsailsoon]

Ricard,

Right now two pucks per week (assuming they are 7 oz and trichlor) are adding 5 ppm per week or a little over 20 ppm per month to your CYA level. So you can build up pretty quickly. CYA doesn't naturally occur so the only way it accumulates is by adding it.

Once you complete the water exchange will you be able to switch to liquid chlorine? If not you have two choices. Plan to drain/refill more frequently or switch to a salt pool for chlorination.

Chris

 

[RicardS]

Hi Chris,

Thank you so much for your reply and explanation. 20 ppm per month in 8 months is a 160 bump to the CYA level. That's a lot and I wasn't aware of that. In a way, I was expecting to keep it at bay by backwashing and topping the pool as I've been doing. So thanks for letting me know.

Right now the CYA level is at 100 and I think my strategy is going to be to work around that level and if I get algae again, draining and refilling half of the pool to SLAM it again. I can get liquid chlorine around here (I bought a 10% chlorine 5 gallon bottle for around $45) or I can get bleach (3.7%) for around $1/gallon. But it's always a hassle to keep carrying bottles.

Once the summer is over, I will look into switching it into a salt pool if I can convince the wife. She's not too keen to have salty water. We have some friends with a salt pool and it was too salty for her liking. But maybe it's not always the case. I will investigate a bit more.

Thanks!

 

[setsailsoon]

Glad to help Ricard. Most people like salt pools much better but there are a few that do not. There isn't a "right - wrong" decision on this. It's just dependent on what your family prefers. We live near the ocean and swim there a lot. Would not like our pool that salty either. But the pool is only 10% of the level of salt . More like spa water.

If you want to try salt there is a way to try it without committing to the high cost cell. Just raise the salt level to the required level and continue using liquid chlorine to maintain FC. Normal chlorination actually produces salt which remains in your pool. After a year or two it's very common that you have over 1000 ppm salt already. The amount of salt required varies by manufacturer and most common is about 3500 ppm. Sea salt is about 35,000 ppm. Definitely do test your salt level before you add salt so you don't accidentally add too much. The best way to test is a Taylor K-1766 kit. It's way more accurate than any other way available to you. Test strips are +/- 500 ppm. If you like salt then order the cell and install it. If not, just replace water until you are back at the previous level. I used this approach since my wife has very sensitive skin and I wasn't sure she'd like it either. Good news for me was she loved it and won't ever let me go non-salt.

Fingers crossed that it works for you. I will say if my wife didn't like it we'd have switched back very quickly.

Chris