So hot! So much CYA!

[bnesheim]

Hi everyone,

Thanks for all the good info. I've been fighting with algae since mother's day and a few minutes on this site convinced me I need to do a partial drain/fill to reduce the CYA from 100ppm. Shooting for 40ppm, but it's not like my pool is graduated so I'll have to guess.

Also looking at adding boric acid once I get everything else under control. Does ~50lbs sound reasonable for 20,000 gallons with a 0 borate level and a 50 ppm target? I've done the numbers a few times but it sounds like so much to add and so much to order.

Thanks again,

Bob

 

[bmoreswim]

Hi Bob! Welcome!! If you do want to add borates, yes, 50 lbs is the correct amount for your pool. You will be our next candidate for a Pool Math guest teacher! My question first would be if you can post up a set of test results, just to make sure we are all on the same page regarding recommendations.

FC
pH
CH
TA
CYA

 

[bnesheim]

This is old data (5/23), I've added 384 fl oz 6% grocery store bleach over the past week (1 gal every other day) and 32 fl oz muriatic acid right after this test.

FC = 2.5
pH = 8.0
CH = 250
TA = 160
CYA = 100

Will start draining tonight and scrub some pesky black algae when it's exposed. At some point that feels like 2/3 drained I will refill and re-test.

I've ordered the boric acid and can get the 10% sodium hypochlorite at lowes. I'll keep the thread alive and post updates.

A little history, bought this house 4 years ago off probate. Pool was a swamp, pump was bad, DE filter was a pain. Replaced pump, filter, and heater. Local company did some maintenance the first season. Did it myself since and started using pucks against all the advice here (got a good deal from someone selling their house). Looks like I'll be starting over. Which is fine, a chance to reinforce the idea of ratios and percents with my kids.

Thanks for the help.

 

[mknauss]

Be sure you read Borates in pool - Further Reading before adding borates.

You will need to lower your TA substantially before adding borates.

 

[bnesheim]

Sure, I've read that. I was concerned with supply chain for the boric acid so I wanted to get it on order.

 

[Wobblerlorri]

Have you done a dilution test on your CYA? The limit of the test is 100, but your actual number may be higher than that.

Get a sample of your water and dilute it by half with tap water. Shake this dilution then test it for CYA. If it still reads 100, dilute it again. You get the actual level by multiplying the first dilution by 2, and the second dilution by 4.

Hopefully you'll get a good number with the first dilution. If you get something like 120, a 50% drain and replace will give you a CYA of 60. If it's much higher than that, you'll need to do two drain and replaces.

 

[bnesheim]

Thanks, I was just reading this in another thread. I'll do that when i get home from the essential business of keeping market share.

 

[PoolNewb2020]

Sure, I've read that. I was concerned with supply chain for the boric acid so I wanted to get it on order.

I ordered 30lbs of boric acid though Walmart online store, which incidentally is fulfilled by Duda industries. The price is the same as ordering straight from Duda. Just make sure to select 10lb, granular crystals bag. It did take almost a month to arrive though.

10 lb Granular Boric Acid H3BO3 99.9+% Pure Orthoboric Acid - Walmart.com

 

[bnesheim]

Cool, thanks. I found it on amazon in 25# bags. It comes out to about $2.25/#. What was the walmart per pound price?

Duda Energy 25 lb Granular Boric Acid H3BO3 99.9+% Pure Orthoboric Acid

 

[PoolNewb2020]

Its $2.37 per pound, if you go with 10lb bags and free shipping. Not every package size from Duda has free shipping.