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I've been reading several threads about removing metal based stains from our pool. Since I would like to do this soon (and try to not wait for a shipment of ascorbic acid). Has anyone used something like this instead?
http://www.intheswim.com/Pool-Chemic...Stain-FreeTM-/
Also, what do I use to reduce the chlorine level to 0 first?
Thanks!
Stain Free by NaturalChemistry IS ascorbic acid....just VERY EXPEN$IVE ascorbic acid. It's almost 3x as much as buying it from the chemical supply.
Thanks Waterbear,
I'm not sure what order to go do things in now. Yesterday I posted our numbers in the "Testing and adjusting pool chemistry" section. There is also staining everywhere, and it responds to vitamin C, so it looks like we have metals. Here are the numbers.
Fc: 14.8
CC: 2.2
PH: below lowest level (when we did the Base demand test we needed 95 drops)
CYA: >100 (since 100 is the first mark, we are guessing ~110)
TA: 30-40
At first I thought we should get the PH up, but maybe we should only get it up a bit, get the chlorine down to 0, and get the stains out first. What do you think?
I don't think I can convince my parents to drain to get the CYA down, at least not yet. Is this high CYA possibly the result of using stabilized chlorine?
Thanks!
You need to get the CYA down first. The high CYA is the result of using staiblized chlorine...no possibly about it! The low pH is also from the trichlor tabs...they are very acidic! I hope you do not have a vinyl pool because you are ruining the liner with the low pH (not so great for plaster either!)Quote:
Originally Posted by illinipdx
CYA can't be accurately measured above about 90 ppm so I would dilute a water sample with an equal part of distilled water and test that then multiply the results by 2.
The first thing I would do is use soda ash to raise both your pH and TA to protect the finish of your pool...Then I would drain and refill to get the CYA down to 30-50 ppm.
Once that is done you can attack the stains. You need to let the chlorine level drop to 1 ppm and get the pH down to about 7.2 before using the ascorbic acid...filter for an hour and then add 1 bottle of seqesterant like Jack's Magic or Metal Magic per 10000 gallons and filter for 24-48 hours until the staining is gone. Then raise your FC with bleach poured into the skimmer 1 ppm per day until the FC is holding (the ascorbic acid will destroy it at first) and then bring it up to about 5 ppm (1 ppm increase per day!)
DO NOT SHOCK THE POOL FOR 2 WEEKS or you risk the staining coming back.
Hope this helps.
it is a vinyl liner pool :(
When you say drain and refill, how far? We can't drain too far, can we?
without a vacumn behind the liner you will have to drain to just a bit below the skimmer and refill repeatedly to dilute the CYA
illinipdx,
I have used Stain Free several times and it works great. Evan is correct that you can get the same thing for $8.50 per lb if you order the 9lb pail through the chemistry store http://www.chemistrystore.com/Ascorbic_Acid.htm. I ordered the 2llb pail last time thanks to Marie (mbar) and it worked great. I'll never buy the Stain Free again unless I'm in a real bind due to its high price.
Now, since you have started the this thread, I have another question that fits within the topic so I'm going to piggy back your thread. Maybe Evan or Richard can help.
How about Oxalic acid? Is it any more dangerous than ascorbic? Does it work for stain removal? Here is the info: http://www.hydropool.com/cgi-bin/hyd...d_chem/pst.htm I recently picked up a 2 lb jar for $15 and thought I might give it a try but I guess I'm a little partial to the ascorbic since I know "it's just vitam C.":)
Dave
From what I know oxalic acid is more toxic than ascorbic acid (if you read the caution statements on the bottle of oxalic acid product that are absent from the ascorbic acid product you will see what I mean) but works in much the same way. It is extremely effective on iron and to the best of my knowledge is the only thing that really works on cobalt staining in fiberglass pools. (Someone please correct me if I am wrong on that!)
Yeah, I noticed that. It did say it was still safe to swim but it definately seems more toxic.Quote:
Originally Posted by waterbear
Do you have any idea what color cobalt stains would be and what would cause them?Quote:
but works in much the same way. It is extremely effective on iron and to the best of my knowledge is the only thing that really works on cobalt staining in fiberglass pools. (Someone please correct me if I am wrong on that!)
Dave
cobalt staining looks like greyish or black spots on the fiberglass. Not sure of the cause but some things I have read seem to point to low calcium levels in the water.