just drained my pool from last year...where to start?

[wverbest]

Last year I had algee bloom somthing terrible. I closed down the pool in disgust without treating it. Just refilled it put in a ton of bleach 6%. Approx 7.5 gal. So now what
Info
27000 galon free form pool
Hayward cartridge filter
Fc reading 0
Ph 6.9
Algee in the water dying...blueish color but still a bunch on the sides. What next...tired of paying pool companies a ton of money with no good result.
Thanks
Wendy

[Watermom]

Hi and welcome to the forum! We will need a complete set of water testing results to be able to do a good job of helping you. We recommend the Taylor K-2006 or 2006C. You can order it from Amazon through the link in my signature, and by doing so, the Pool Forum makes a little money, too!

Most important, is to raise your pH. Any reading below 7.0 is acidic and can damage your pool. Test kits cannot differentiate below 6.9, so your pH may actually be lower than that. You can use 20 Mule Team Borax (laundry aisle at Walmart) to raise the pH. Start with adding a half a box slowly into the skimmer while the pump is running, breaking up any clumps. After a few hours, retest and redose as needed until you get to 7.4-7.6 although anywhere from 7.2-7.8 is ok.

To clear the algae, test as many times a day as you can, a minimum of twice and three times or more is even better, and each time, add enough bleach to get back up to shock level. If you have no CYA as I assume since you have just freshly filled your pool, a shock level of around 12ppm should be fine. In a 27K pool, each quart of 6% bleach will add approximately 0.5ppm of chlorine. Once you can go from sundown one evening from sunup the next morning without losing more than 1ppm of chlorine, you can assume the algae is dead. Run the pump 24/7 while you are trying to clear the pool and allow your filter to do its job of filtering out the dead algae. You may need to clean your cartridge periodically as it filters out the dead algae.
(By the way, it is OK to add doses of Borax and bleach at the same time with no problems. I do so all the time.)

What type of pool is this -- vinyl liner, gunite, fiberglass?

Another idea -- you could use dichlor powder to shock with for awhile if you currently have no CYA. Dichlor will add CYA at the same time as chlorine. But, keep an eye on the CYA level if you do use it. You will want around 40ppm of CYA and once you get to that level, you'll want to either switch to bleach or maybe Cal-Hypo for your source of chlorine.

Repost if you have further questions.

[CarlD]

Since you said it's free-form, I'm guessing you have a hard liner--concrete/gunite/shotcrete/plaster or tile. In which case, your pH won't hurt your pool. If it's vinyl, you need pH to be at a minimum 7.0.
When you added 7.5 gallons of 6%, you would have added 16 2/3ppm of free chlorine. If your CYA is 60ppm or higher, that won't be enough. Your FC dropped to 0. That tells me you probably have no CYA and lots of algae (algae WILL consume CYA after a couple of months of no cleanup).

So, follow WaterMom's advice.

FYI: for your 27,000 gallons, one gallon of 6% adds 2.2 ppm of chlorine. Figure accordingly. If you use 12.5% LC (Liquid Chlorine), each gallon will add 4.6 ppm of chlorine. Regular 5.25% bleach will add just under 2 ppm per gallon.

[wverbest]

Yes gunite pool...
New numbers
cl:15
Ph:7.2
Alk: 100
Hardness:170
Cya:less than30 as the black dot did not disappear

[Watermom]

Ok, good. PH of 7.2 is just fine. The key to clearing up algae is sustain the high cl reading. Try and test and add chlorine in some form several times each day and keep the pump running to filter out the dead stuff. Keep us posted with how it is going.

[wverbest]

Thank you so much..I will keep you posted

[CarlD]

If you use Dichlor powder or Tri-chlor tablets, watch your pH. Both tend to push it down. But bleach and cal-hypo won't have that effect, and cal-hypo will add calcium, which you, with a gunite pool, want to be between 200 and 400ppm--you are a little low. Calcium protects the walls and keeps calcium carbonated from leeching out. Useless on vinyl and probably useless on fiberglass.

[wverbest]

So far so good...pool completely clear in just two days...all green killed. ..your method works...thank you thank you thank you

[CarlD]

Always good to hear! Thanks for letting us know!

Carl