Pool sitting for a friend with algae

[wmwinn]

First of all, I'm a solid believer in the BBB method. In fact, I was bragging about my ability to clear up troubled pool water, when a good friend of mine left town - and challenged me to help him out with his pool water.

I know he's been frustrated with light green algae the last few weeks, and he's been throwing a bunch of di-chlor shock into the pool to try and clear it up. I went over tonight, in anticipation of adding some bleach and testing every 30min or so. But, after these test results, I'm a bit confused what to do next.

temp=78
FC=34
CC=0
pH=7.4
TA=130
CH=170
CYA = 120


I immediately jumped on the high CYA reading, and was all ready to dilute with fresh water, but then I remembered his water is pretty cloudy already. That should drive a higher than actual reading for CYA, correct?

He's got enough FC - maybe it's just gonna take a long time to clear? Any other recommendations?

thanks,
- Mark -

 

[JohnN]

It takes very cloudy water to affect the CYA test. To see if it is skewing the reading, fill the tube up with just plain pool water and see if you can see the dot all the way to the top. If you can, then do the diluted test and go from there.

 

[wmwinn]

Good advice, John. I'll try that tomorrow and post the results.

 

[duraleigh]

It takes very cloudy water to affect the CYA test.

Exactly correct. I would even say VERY VERY cloudy to make any difference.

 

[Donldson]

I know he's been frustrated with light green algae the last few weeks, and he's been throwing a bunch of di-chlor shock into the pool to try and clear it up.

Friends don't let friends use dichlor

Odds are your CYA reading wasn't skewed by the cloudiness. If you can see 3 inches in to the water then it's plenty clear for the test. You do need to do the 50/50 test, depending on what "a bunch of dichlor" is it could be far above 120 (because of the logarithmic scale of the CYA test it becomes impossible to read over 100, that's why it stops there). So redo the test, get ready to drain him back to 50 ppm if you can, and show that boy what BBB can do!

Remember: You aren't just doing this for yourself. You are fighting for the honor of all TFP members everywhere! Do us proud

 

[zea3]

Try diluting the pool water with an equal part of tap water then run the CYA test again and double the result. That should give you a ballpark estimate of how high the CYA really is.

 

[wmwinn]

When filling the CYA tube with pool water, there was NO issue seeing the black dot very clearly at bottom. So, that tells me I can trust the CYA reading. Since it was past the maximum scale (logarithmic), I tried the 50% tap water dilution method and got a reading of 80, so the actual CYA level must be 160. WOW!!

Looks like I'll be draining half the water, and refilling with tap water to try and hit 80ppm. (And convince my friend not to use di-chlor again)

The algae looks to be yellowish, but I'm not entirely sure it's Mustard. There are a lot of pine trees surrounding the pool that are losing most of their needles due to the drought. Might be pollen from that?

thanks for your guidance - will continue to post my results so that others may benefit from this.
- Mark -

 

[wmwinn]

OK - Yesterday, I drained half of the murky water, and replaced with tap water. CYA was reduced from 160 to 70ppm. Yay!

To battle the mustard algae (if that's what it is), I adjusted pH to 7.2 using Muriatic Acid, and then added bleach to bring FC from 15ppm up to 37ppm after sundown. At sunrise this morning, the FC hadn't reduced much - still sitting at 36ppm. (all FC measurements are using FAS-DPD)

Since FC wasn't reduced overnight battling organic compounds, Do these results indicate this is NOT an algae problem?

The more I read about spruce tree pollen, I'm wondering if that's what my friend has in the pool. I'm gonna try a skimmer sock and see what that shows.

Other ideas?
- Mark -

 

[Charlie_R]

What was the CC on your latest test?

I'd still leave it at SLAM levels for a day or two, with OCLT every night.

The skimmer sock is a good idea with trees nearby.

 

[wmwinn]

Sorry, forgot to include that info.
Night: FC=37 CC=0.5, Morning: FC=36, CC=0.5

 

[techguy]

The pine trees produce a lot if yellow pollen that's likely to turn green/brown and clumpy on the floor. Sounds like if you vacuumed it to waste, you will save yourself headaches. I am basing my comments on the amount of yellow pollen that coats my truck at my office where we have rows of pine trees I n the parking lots and the way it doesn't wash off the windshield easily.

 

[sreil1]

Hello!
I am the friend that wmwinn was pool sitting for. This is the perfect place to thank him for his work on our pool while we were on vacation! The pool is just about "sparkling" blue. The kids were very excited to swim again when we got back.

I tried the BBB method for a short period last year with not very good results. But this wasn't due to the method, but to my lack of following it very well. We don't cover our pool very often, only with the solar cover when we want to raise it above the 80-82 it normally sits at. This was an issue last year because I didn't keep track of my CYA so my chlorine didn't stick around. So, I have ordered my TF Test Kit and will do a better job monitoring all of my chemistry (not just ph and FC through my DPD kit from my pool store). I will keep a better eye on my CYA this time. I am going to read and learn more about the BBB method and start next year fully on the BBB plan. For the rest of this year, I am going to burn through my tub of trichlor tablets and shock with bleach from Costco. I figure the trichlor will help keep my CYA up without adding too much through the dichlor "shock" I've been using. If I need a CYA boost I will put a sock in the skimmer as needed.

Thank you to all those who replyed here and especially wmwinn for his help getting our pool back to a swimming state!

 

[anonapersona]

How long is the swimming season there in Albuquerque? You might be better off to hang on to the trichlor tablets to use when you are on vacation and go to bleach for daily chlorination now, since your CYA is still too high even now.

 

[Donldson]

Welcome to TFP.

You seem to be under the impression that CYA goes away over time, am I right? If so you are in for a shock! (pun intended ) It doesn't go away and you don't need to "keep the CYA up". You are really on the upper end of manageable to begin with, raising it more is asking for trouble.

If you want to keep using the tablets you need to drain a few inches from your pool and refill every week while testing your CYA weekly as well. This will help keep things in check and prevent the pool from going green again. You could also switch to bleach and avoid having to drain any water. Each has it's pros and cons, it's your call.