View Full Version : Removing iron in solution
Lademers
05-18-2014, 02:25 PM
The pool water turned brown when I brought the chorine level up to 1pp. Metal out cleared to pool water over night, a little oxalic acid removed the stain from the steps. Is the iron in solution? Will it precipitated back out when I add the chlorine back in? What is my next step?
Pool is 20,000gallon vinyl liner. The water was replaced with the new liner.
BigDave
06-09-2014, 12:51 PM
First: I'm sorry you didn't get a resonse for so long.
Second: I have no experience removing metals from pool water but I'll give you what I've learned here.
Here goes:
I think Metal Out(looks like there are a few products named Metal Out) is an HEDP sequestrant which should bind up the metals in solution leaving clear water with the metals still in the water. The acid would clear the stain by lowering the pH returning the stain to solution where the metal out could bind it up.
Sound's great, but, the metal's still there and raising the chlorine or the pH could bring it out again. The sequstrant will also degrade and additional additions will be required. I've seen a couple ways to try to remove the metals altogether.
One is CuLater which is a packet containing a material that will pull the metal out of solution and hold it. This appears to work for some of the pool owners here who have used it. They usually put the packet in the skimmer under a skimmer sock to keep the packet from getting fouled.
The other is only for pools with sand filters and no chlorine feeders and no recent history of stabilizer / dichlor / trichlor in the skimmer. The idea is to slowly bring up the pool's chlorine by adding small amounts of calcium hypochlorite through the skimmer. The cal-hypo dissolves on the sand bed creating a high chlorine/ high pH zone encouraging the metal to drop out of solution onto the filter. The cal-hypo also leaves some calcium precipitate which helps collect the metal. Backwash it out. But remember - Sand filter, no dichlor, no trichlor, no CYA.
Let us know how it's going.
Lademers
06-09-2014, 02:02 PM
I brought a sample to my pool store, they tested and saw no metals! On their instructions I brought the total alkalinity up, then brought the ph down, then added stabilizer, and then the chlorine. So far so good! My water has been clear as can be.
BigDave
06-09-2014, 02:46 PM
Great! Glad to hear it worked out.
Keep a weather eye out for staining - it sure sounds like you had metal and sequestered it. Perhaps the test can't detect sequestered metals?
Watermom
06-09-2014, 07:20 PM
Dave, thanks for catching that this post had never been answered. Sometimes they are accidentally missed and sneak past us and then get buried under newer posts.