This Algae is killing me

[jverhage]

I rescued my pool at the beginning of the year from an algae bloom that occurred right before closing, using the SLAM method. I have been using the TFP liquid chlorine method(10% HTH liquid chlorine) of maintaining my pool all summer. The sand in my filter is 2 years old. My water has been clear, but not crystal clear all summer, but I have needed to vacuum algae and/or debris off the bottom almost every day. I have SLAMed the pool twice. The first time removed the algae growth for about a week or two. This time I have algae re-growing overnight at chlorine levels of 16 PPM - 19 PPM with no FC loss overnight. I've been reading all of the Algae articles, and I'm baffled. Do I have regular algae, mustard algae, pollen???

FC - 10
CC - 0
TA - 90
PH - 7.6
CYA - 40

Can someone please help me figure out this problem? Thanks in advance for any assistance!!!

 

[woodyp]

Got a pic? Is sounds like you never, ever, truly passed the 3 criteria for a SLAM to me.

 

[S1ngram]

There are three requirements to passing OCLT: no more than one ppm fc loss overnight, cc of .5 or less and clear water (can read heads or tails on coin on bottom of pool). Since you say your water is clear, but not crystal, it's possible your SLAM was not quite done when you stopped.

Since I don't know where you live, it's hard to say if pollen might be affecting your pool. Look around at other surfaces near the pool. Are they covered with dust or pollen? If so, your pool is too.

How are you testing your water? Do you have one of the recommended test kits from this site?

With a CYA of 40, you are keeping your fc awfully high. My fc is 40 and I shoot for fc 7 and don't let it go below 4.

Your sand is fine at 2 years old. There are instructions for deep cleaning a sand filter in pool school. Also, you might consider adding zeofiber or DE to your filter to help filter out smaller particles. I do that with my filter after I add well water to my pool.

Just some ideas/suggestions to get you started. I'm sure more folks will post soon with additional info for you too.

 

[GarlicCity]

Your sand is fine at 2 years old. There are instructions for deep cleaning a sand filter in pool school. Also, you might consider adding zeofiber or DE to your filter to help filter out smaller particles. I do that with my filter after I add well water to my pool.

^^^^^^This^^^^^^

 

[BuckeyeChris]

If you had the pump running overnight, tested well after adding bleach, and have no OCL then it's hard to say it's an algae problem. Have you taken some out and felt it, smeared it on some white paper?

 

[jverhage]

Yes, I am using the FAS-DPD Chlorine test kit. During the original SLAM I only passed 2 of the criteria, the water was cloudy, but it was due to Iron. Once I put metal remover in, the water cleared. My water is clear enough to read heads or tails on a quarter, but it has a very slight haze to the water. I'm not sure how to describe this better. I was only keeping my FC that high for slamming. At other times, I was keeping it at 3-4. It would routinely drop to 1.5 or 1.0

 

[bobodaclown]

If your FC level drops below the level recommended for your CYA level Pool School - Chlorine / CYA Chart then algae can take hold. You should start the SLAM all over again until you pass ALL criteria. You can choose not to follow the advise and lean my trial and error, the choice is yours.

Pool School - SLAM - Shock Level And Maintain

 

[jverhage]

I appreciate all of the advice, and will follow it. It sounds like I made 2 major mistakes.
1) Initial SLAM not completed properly. (I think that I was "Pool Stored" with the Iron in the water reading)
2) I was not maintaining my chlorine levels above the prescribed minimum.
I was trying not to keep my chlorine level too high because I read that levels above 4 PPM is harmful to humans. But it seems that everyone who knows a LOT more than I do about pool chemistry keep their levels higher than 4.
I will re-SLAM. Once I pass all 3 tests, maintain my chlorine at 6-7. If I have misinterpreted anything, please let me know.
Thanks to everyone for all of their help!!!

 

[bobodaclown]

No worries. If you had no CYA (stabilizer) then it would be a concern. We're here to help and we've been where you are. Stay strong.

 

[Beens]

As bobo said, it's all about the cya.
All the talk of chlorine at 1-3 always ignores the existence and effect of cya.

The chlorine/cya chart and the levels recommended here are all based on the fact that cya protects and buffers chlorine. It makes it less harsh.

So as long as you're following the chart and you don't go crazy over the recommended SLAM levels, the chlorine level will be safe for you and your pool equipment.

I don't recall all the exact formulas except that without cya even low levels of chlorine are significantly more harsh than a pool with cya and much higher levels.

My cya is 30 and for regular maintenance I dose to 8 every day. (it usually tests at 5-6fc and I raise it from there). I want to make sure it never goes below my minimum.

 

[kimkats]

I keep my FC at 7 daily! The levels TFP uses are scientifically proven to be safe and effective for a pool and the people who enjoy them. Use our levels and your pool will be the jewel of the neighborhood!

Kim