How can I tell if I have algae?

[FormerBromineUser]

Been thinking.... Can you bite the bullet and get your FC up to 30? ChemGeek has recommended that your shock level be 40% of your CYA. That would put you at 48. Yikes. Lots of bleach. So I am thinking 30, rather than 25 would help a little. Also, rather than only adding once a day, do it twice a day.

[RaceAngel88]

Yes, I can definitely do that. I was tempted to put more bleach in this morning when I found it was only at 22. I'm willing to put bleach in 2 or even 3 times a day if necessary to get rid of any potential algae. Once I've got it at 30, and can maintain that level, how many days do I keep it there? I assume it's safe for me to get in the water to vacuum it, etc. at 30, correct? I think it just has the potential to make clothing fade at that level.

[FormerBromineUser]

Yes, it would safe to get in as you would still actually be below "shock level" for your CYA. Old swim suits are always advised when FC is above your "max" level on the best guess chart.

Testing and adding chlorine to maintain that 30 level 3 times a day would be great! You need to keep at it until the water is clear, there are no signs of algae, and you can pass the overnight test. Do you know how to do that?

[RaceAngel88]

Yes, I know how to do the overnight test, but with the CYA that high am I still looking to make sure there is not an FC loss of 1 ppm or greater?

[FormerBromineUser]

Maybe not, but let's see how it goes. I followed a thread where we stopped a high shock level slam at 2ppm loss, but that was after watching all other numbers very carefully. Again, let's see how it goes.

[chem geek]

Regarding chlorine oxidation of CYA, see Degradation of Cyanuric Acid. It take about 2.5 ppm FC to oxidize every 1 ppm of CYA. Lowering the CYA by 150 ppm would take 375 ppm FC so maintaining a high chlorine level over quite an extended period of time. It's not usually a very cost-effective way to lower it particularly if water replacement is not too expensive. In 12,000 gallons, 375 ppm FC is 35 gallons of 12.5% chlorinating liquid which at $4/gallon would be $140. 12,000 gallons is 16 ccf so water replacement would be comparable in price if it were $8.75 per ccf.

[FormerBromineUser]

I have horrible well-water too. I try to harvest rainwater as much as possible for my refills. But, I also purchased an expensive Hydropure MetalTrap which fits on the end of your hose. It does help. I then add the water into the skimmer so that the filter can trap a little of the metals too.