Algae - HELP!

[Lshannon]

Hi!
I just joined this forum/website- don't ask why I haven't found it before! So, I'm a first time poster!!

We are in desperate need of some help....we have a huge algae problem!

Here are the details:
Vinyl Liner pool - in ground
Around 3 feet deep in shallow end, about 8 feet deep in deep end
Just under 30,000 gallons
I had a chemical test done today at the local pool store and below is the read out:
CYA: 86
Total Chlorine: 7
Free Chlorine: 5.7
PH: 7.6
Total Alkalinity: 120
Adj.Total Alkalinity: 94
Total Hardness: 100

We just added some "filtration aid" to the skimmer line. We have a Hayward Sand Filter system.

As you see from the pic, it is BAD. I asked the people at the pool store how to "kill" the algae - they claim my high chlorine should be doing it (adding super chlorine) on Saturday.

can anyone help? Of course we are having a heat crazy now, and it is predicted to be near 100 for the next 7 days in good 'ol Iowa.

Thanks in advance!

 

[jblizzle]

Welcome to TFP!!!

The short answer is that you need to get yourself one of the Recommended Test Kits because pool store testing is notoriously bad and not accurate enough. And you need to SLAM the pool. [slam:34peeax0][/slam:34peeax0]

I would recommend getting the TF-100 with the XL option because you have a good bit of SLAMing to do.
While waiting for the kit, you should read the articles in Pool School (at least the first few) to start to understand the chemisty, the most important being the relationship of CYA and FC which 99% of pool store employees do NOT understand. For example, if (big IF here) your CYA is really ~90ppm, the minimum you FC level should be to prevent algae from starting is 7ppm and once algae has started you need to maintain the FC shock level of 35ppm for the SLAM process. Your FC is WAY WAY WAY too low to kill the algae off.

You need to verify your CYA with your own test kit. Then likely replace water to lower the CYA into the 30-50ppm recommended range. Then SLAM away.

 

[pwrstrk]

Welcome to TFP !!

+ 1. That was good advice jblizzle gave you. The TF100 kit is a must have to clear your pool. When you get the kit post a full set of results and we can get you started on SLAMMing.

 

[BayScoutTim]

Welcome to TFP!

You have come to the right place to get this resolved. I recently went through the same thing but mine looked worse. The "Doctors" will be by shortly but I can start with a few pointers.

You need a test kit to test yourself. The Taylor K-2006 or the better bargain is the TF-100 Test kit. This will allow you to perform all the test necessary in a timely manner.

Read through the Pool School to understand the proper way to SLAM your pool. This is a process to raise the chlorine high enough to kill the algae in your pool. Vacuuming and brushing all the while to keep algae from building up.

As a side note, I bought 2 packs of filter socks to collect the dead algae. This prevents it from collecting in your sand filter and reduces backwashes. When the filter sock get clogged you can just dry it out in the sun and brush the algae off. You will go through 4 or 5 socks in the beginning.

Other members will be along shortly to give you some great advice. Your pool will be sparkling in no time.

Best reguards

 

[Lshannon]

OK, thanks for the info. Question though: or help me with the equation at least: how much chlorine (if bought as liquid chlorine from the grocery store), in gallons, would I need for my 30,000 gallon pool? Can someone walk through a "mock' equation so I can better understand this formula? Thanks! I noticed that 1 gallon of bleach is based on it's percentage of bleach (IE, 6%), and it states that the percentage of bleach raises your FC about the same PPM. Do I have this right? Can someone walk through an example? Thanks!!

 

[Lshannon]

One other question: You mentioned my CYA should be in the 30-50 range, but I've also read reports that if our pool is "mostly" under direct sunlight, we could have a higher range of CYA. I would venture to say that our pool is in direct sunlight about 60-70% or more in direct sunlight each day. Does that matter? Thanks!

 

[jblizzle]

Check out poolcalculator.com that will calculate the amount of bleach needed for a certain FC rise based on you pool size.

Easier to add CYA than remove it. So start around 40ppm and add if needed. Rarely need more than 50ppm.

 

[Swami]

Greetings Lshannon,

Last week my pool was as green as yours. So, I just joined TFP too. I don't yet have the FT-100kit, it is on its way. My pool is about the same size as yours. I poured a gallon of chlorine every hour. A total of 20 gallons. No more green. The pool is milky. I understand it takes a week to clear up. Now I vacuum it in the mornings and backwash till the white is all gone. If I had the kit I would have monitored the Free Chlorine. I found these articles from the Pool School to be very helpful: Defeating Algae and SLAMing your pool.

Best wishes, Swami

 

[Tanner M]

That pool does not look any where near 30,000 gallons. If the depths you mentioned are correct and your pool does not go much further back from what the photo shows I would estimate that pool to be closer to 18,000-20,000 gallons.

 

[RobbieH]

Agreed. 30,000 is an unusually large pool.

To answer your question the best I can about how much bleach... a LOT. The store, Costco, and Sams are going to think you own a laundry.

Since you are already green, I'd do a partial drain and fill, about half your water, to get that CYA down to half what it is now. And, even better, get the TF-100 and measure it yourself - pool stores are notorious for getting the CYA measurement wrong.

 

[Lshannon]

Thanks for the info!

To clarify my pool size: it's 18x36. 3 feet deep in shallow end and 8.5 feet in deep end. According to my calculations, that would equal about 27,000 gallons. Correct me if I'm wrong?

 

[jblizzle]

That is probably closer than 30k. The tough part is coming up with the average depth.

 

[Bama Rambler]

I get about 25,000 gallons. Actually a little shy of that.

 

[Jeetyet]

Using the depths in your first post (3' and 8') I get...... 26,659 gals
Using the depths in your later post (3' and 8.5') I get... 27,870 gals

All of the pool volume calculations here and other places are just estimates to get you in the ballpark anyway because you'd have to have detailed measurements of the trapezoidal hopper in the deep end to get anywhere near accurate results. In other words anywhere from 25k to 28k will give you a "close enough" estimate for making most adjustments as you can change the doses up or down a bit as you go along if your results aren't spot on what you were expecting.