Pool calculator to get rid of ammonia

[DIY]

Hi... this forum is sooooo helpful, but I cannot find the exact answer I'm looking for. I am confused about how much chlorine is needed to rid my pool of ammonia.

I live in Southeast PA, so pools must be closed for the winter. Last summer, had a problem holding chlorine and determined I had sky-high CYA (from years of tri-chlor and di-chlor). Partially drained in August and refilled. Closed the pool in September to approx. 90ppm CYA. Opened 10 days ago to zero CYA and sky-high pH. Everything I've read seems like an ammonia problem, and the test confirmed 6+ppm (highest reading available was 6, so it may be higher...)

My questions:

1. I cannot find a calculator to determine just how much chlorine is needed to get rid of the ammonia. All I read is "A LOT," but that tells me little
2. Can I do this gradually, or must it be big-bang/all-or-nothing?
3. Can I use cal-hypo or di-chlor to do this, or must it be liquid chlorine?

My stats:

• 22,500 gallons, white plaster
• Currently pH neutral (7.4)
• CYA = close to nothing!

THANKS!!!
Jen

 

[JoyfulNoise]

There isn't an exact number to put on it because the ammonia/chlorine reactions can be a little complicated (multiple different reactions, each with their own rates and equilibrium values). The best rule of thumb is that it takes approximately 10X the amount of ammonia concentration in FC to neutralize the ammonia. So, if your pool does indeed have 6ppm ammonia (did you measure it with an aquarium test kit?), then it is going to take a minimum of 60ppm FC to neutralize it. You can use Pool Math to figure out how much bleach that is.

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Best to use liquid chlorine (as strong as you can get it) to do the neutralization. Dichlor or cal-hypo will add too much stabilizer and/or calcium to your water.

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I calculate to go form 0ppm to 60ppm FC in a 22,500 gallon pool, you will need ~ 13 gallons of 10% LC. I would add it at a rate of 4 gallons at a time and then check 10-15mins after adding each batch to see if your FC is holding at all. Make sure your pump is running (high speed is best if your have a variable speed pump) and be sure to really brush the pool well to ensure good mixing.

Add all chemicals in front of the deep end pool return, never into the skimmer.

 

[Richard320]

Somewhere I know there's the chemical explanation but from memory, it's something like 10X chlorine to Ammonia. If you've tested the ammonia using an ammonia test (aquarium store) and it says 6, that means 60 FC just to eliminate the ammonia and who knows how much more to kill any algae.

To raise 22500 gallons of water from zero to 60 FC will take 16 jugs of bleach. That's like fifty bucks. What if the ammonia is 10? There's a hundred bucks' worth of bleach just to get to neutral! Plus how much more to treat the algae?

It will probably be cheaper to drain than to treat if indeed you tested ammonia with an ammonia test kit. You'll still need to SLAM when it's refilled to get rid of any residual algae, but that will be some reasonable amount of bleach that can fit in one shopping cart, not this: