Before getting bulk ascorbic acid for pools, you should first make sure that ascorbic acid would help with the stain in the first place so you can try a vitamin C tablet locally.
If that works, then a broader treatment should work and if it doesn’t the first time then you should re-do it, again, this time with an even higher dosage.
Note: Chlorine and ascorbic acid cancel each other out so ensure your pool FC levels are small before trying this. Or else, they’d cancel each other out.
Although iron stains can be removed with ease by ascorbic acid, copper stains can prove to be much more harder. Even, stains that aren’t metal, such as organic stains won’t be affected much by ascorbic acid (organic stains do fade from chlorine with time, including a Trichor puck rubbed on them for plaster pools — do not ever rub Trichlor pucks on vinyl).
Where to Buy Ascorbic Acid for Pools
You can buy ascorbic acid (in large quantities) from Amazon, but you MUST properly follow procedures for treating the pool including lowering the FC level and Ph before using the ascorbic acid.
Here are two links to buy ascorbic acid:
How to Treat Pool with Ascorbic Acid
To treat your pool using ascorbic acid, do the following:
Bring Down Chlorine Levels
Reduce your chlorine down to 0 and PH down to 7.2. High chlorine in the water in the water won’t hurt, it will just cancel out the ascorbic acid, so you end up using more to get rid of the stains. You can add poyquat 60 per directions on the bottle to avoid getting algae while the chlorine is low.
You will need about a half to one pound of ascorbic acid per 10,000 gal. I like to go lighter on it and see if all the stains lift off before adding more.
Put the filter on circulate.
Using a cup, you need to around the pool’s perimeter and drop it down the sides as you go.
Then allow the acid move around the pool for ½ hour. It will surprise you how quickly the stain will just disappear before your eyes.
If the stains don’t go, then you should leave the filter to circulate and add more ascorbic acid close to where stains are still present. Next, let it circulate until all the stains are no longer visible.
You should repeat the process if stain still continues to exist until you get your desired result.
Once the stain has been completely eradicated, add enough sequestering agent for the volume of your pool – adding more is better than not enough.
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Put the filter back on filter and leave it on 24/7.
Remember, ascorbic acid may bring your alkalinity and PH down so once a whole day has passed. You should begin attempting rebalancing your pool’s water.
Bring your PH and alkalinity up – Try Arm and Hammer washing soda (CHECK ON AMAZON) first, that should raise both Alk and PH UP.
Next, test in between since you don’t want your PH to reach heights higher than 7.2. If your alkalinity is in range, and you still need to raise your PH, then use Borax to take it up no higher than 7.2.
Bringing up chlorine should be done slowly. It will eat up lots of chlorine – so I recommend using bleach only at this time, and try to take it up to your minimum chlorine for your cya according to the Chlorine / CYA Chart – Trouble Free Pool.
Once you begin to gradually raise the chlorine, watch out for stains that begin to form. If you see any, ensure the PH is no higher than 7.2, and add more sequestering agent. You should see the stain lift in a couple of hours. Avoid shocking! Do not shock for at least 14 days! Ensure your PH is low (7.2) for 7 days or 14 days – It won’t be difficult since the sequestering agent and ascorbic acid will help it remain low.
Once your chlorine starts to hold, it means that you have used up the ascorbic acid in the water and it will be easy to rebalance the pool back to your regular parameters.
Note: High PH plus high chlorine will precipitate any remaining metal that is not sequestered out of the water and on to the surface of the pool again. If such is the situation, you’re in, then take the PH back down to 7, or 7.2 and add extra sequestering agent. That should lift the stain off.
You can only add polyquat 60 to the water before starting the stain treatment to avoid getting algae while the chlorine is low.