About to SLAM the pool for mustard Algae - help with chlorine

[Eug]

Hello gang - looks like I've got mustard algae on my walls. First I've got to drain some of the pool to lower my CYA. CYA is currently over 100, and from reading some of the info on here I'm guessing it's gotten higher due to the chlorine pucks I'm using. Also wondering if the shock bags we use are raising the CYA also.

So first, where do you get the liguid bleach/chlorine to us to shock the pool? Also sounds like I should be using liquid going forward anyway instead of the 1 lb. bags.

 

[woodyp]

If the 1 lb. bags are dichlor...yes....it has CYA. 10% bleach can be had at Walmart.

 

[Eug]

Thanks woodyp! Just found another thread that helped answer a lot of questions about the liquid bleach. Headed to the store now to load up!

 

[Chasscos]

As I compared across stores, homedepot is the cheapest on liquid chlorine. But if kroger runs promotion, it is even cheaper than home depot. I have fry's(under kroger) in Arizona and have been using it for a while.

 

[Eug]

Haven't slammed just yet. Leaving on Saturday morning for a 5 day trip and don't think I'll have enough time to finish. But there is a teenager who'll be present I may leave to finish up if I do go ahead and start tonight. Which I think I am because I don't want things to get worse. So I'm going to lay out where I am as best as possible. If any of you have additional questions please ask.

Have really high CYA, I'm guessing from my chlorine pucks. Need to do some research on that soon as well. Emptied out about 18" of water and then used a bag of Bio-Active 2 days ago and it has helped lower my CYA. Currently I'm at CYA 140. I'm thinking about slamming the pool starting tonight with the Pool Essentials Chlorinating Liquid (10% Sodium Hypochlorite). That's all I've been using since realizing I have high CYA and also reading this forum. Then when I get back in about 6 days, maybe continuing to lower the pool and refilling until I get to the desired level of CYA. May also just add another bag of Bio-Active and refill as the sun burns it off.

Here goes - Current Levels:
FC = 0
TC = 0 (it was 1.5 two days ago)
CC = 0
pH = 7.2
TA = 120
CH = 270

Here is where I'm getting stuck. Just how much of the product do I need to start this? It looks like I want to be at a minimum 46 on my FC reading to start the shock process? The Pool Treatment product tells me 1 gallon for each 10,000 gallons of water will yield 5-10 ppm of chlorine residue. At 25,000 gallons (not 30k as previously mentioned), I looking at adding a minimum 15 gallons of product tonight. Below is how I got to that number:

Average of 5-10 chlorine from one gallon is 7.5
46 minimum chlorine level needed / 7.5 = 6.13 gallons for 10,000 gallons of pool water.
6.13 x 2.5 (for 25,000 gallons of pool water) = 15.325 gallons

Am I even close here? Or just totally spanking up this entire process? I may just go into a corner of the house, lie in a fetal position sucking my thumb, and give up!