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Thread: Iron Staining and HTH Metal Control

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    Join Date
    Jun 2009
    Location
    Dayton, OH
    Posts
    10

    Iron Staining and HTH Metal Control

    I thought I would post my recent success using HTH Metal Control to remove some iron staining in my pool but first a little background information...our pool install was completed last October, filled with water and started up to make sure there were no pluming leaks, all the equipment worked, etc. The following day I took water to Leslie's for initial testing with the following results:

    FC - 0
    TC - 0
    pH - 7.8
    TA - 110
    CH - 190
    CYA - 0
    Cu, Fe, phosphates and salt were all zero.

    All results were identical to my LaMotte kits with the exception of metals and salt which I did not test. Two 182oz jugs of bleach were added with about a half gallon added daily to keep some FC in the water. I wasn't testing regularly since we weren't swimming in the pool, I just wanted to keep it clear. I closed the pool in mid November when I finally got tired of cleaning leaves out of it

    Fast forward to early April...I opened the pool and it was full to the rim with green water. Excess water was drained, 3 lbs of CYA were added and the shock process was started and completed in about a week. I took the water to Leslie's again and the pH, TA and CH and CYA remained the same as above. At this point nothing other than bleach and CYA had been added to the pool. Leslie's did try to sell me some Alkalinity increaser and pH decreaser but I told them I had some and left. Funny how they didn't try to sell me any CYA since their test results indicated zero.

    The pool remained crystal clear up until the constant rains of last week. I didn't test much due to the rain which raised the pool volume by 2-3 inches and also considerably clouded the water. After a round of tests my FC and TC were zero and my pH still tested at 7.8 (upper limit of kit) so I started the shock process again. Friday's weekly TA test indicated that the TA had risen to 140! Now that the water was clear again I noticed an orange ring around the pool. The Vitamin C test indicated iron staining so I started to lower the TA and pH to try and control the staining. I was able to lower my TA to 110 and get my pH to 7.5 on Saturday with one round of MA treatment.

    I found HTH Metal Control for $11 at Wal Mart while grocery shopping Monday morning. I figured it was worth a try since I was going to need a sequestrate anyway and this was an HEDP product which is recommended here. One quart per 10,000g is the recommended dosage for a newly opened pool and two quarts is recommended per 10,000g as a stain treatment. I purchased two quarts.

    After reading about sprinkling Ascorbic Acid down the sides of the pool to eliminate staining I figured why not? I turned off the filtration, got in the pool (probably not the smartest thing to do), pressed the bottle against the wall and started slowly squeezing the HTH Metal Control around the perimeter of the pool. I could actually watch the acid moving down the wall as I applied it. The first quart made it about three quarters around the pool so I opened the second bottle and finished. By the time I got back to were I started I could see some of the stains had already disappeared where I first applied it! Some spots were clear and some were "streaky".

    Since the directions say to leave the filtration running and brush the pool I restarted the filter and brushed. After about an hour I came back and the sides were still stained so I added the rest of the second bottle to the pool, left the filter on, brushed the sides again and went inside. A couple of hours later the sides were completely stain free and the slight staining on the steps and bench were also gone!!!

    Out of curiosity I tested the water:

    FC - 0
    TC - 0
    pH - 6.8 (or lower)
    TA - 90

    The HTH Metal Control seems to have used up a good deal of chlorine, reduced my TA around 20ppm and dropped the pH at least 0.7 and probably more. An afternoon of aeration and the pH appears to be steady at 7.5 with the TA at 90. Both the pH and TA are the same as of this morning's readings.

    I'm unsure if my results were atypical since my pool is new, the stains were new, or if it was my application method (again, probably not the best idea to apply this while in the pool) but it seems to have worked wonders for me. I now wish I would have been more patient and allowed the metal control to work overnight to see if a smaller dosage would have worked but I'm still happy the stains are gone

    If I am not mistaken, I will now need to try and lower my TA a bit more to get my pH in the 7.2 - 7.4 range to prevent the stains from returning in the event I need to shock the pool again.
    Matt

    10,000g "Antigua" (kidney shape) fiberglass IG pool, 1 hp Hayward Super Pump, Hayward 1200 Cart filter, 130K BTU heater, Savi Melody lights.

  2. Back To Top    #2

    Join Date
    Jun 2009
    Location
    Dayton, OH
    Posts
    10

    Re: Iron Staining and HTH Metal Control

    After a couple of weeks of not adding any more Metal Control to the pool the stains returned They were not nearly as noticeable as before but the pool seems a bit less "sparkly" when it is stained even though no one seems to notice but me. Yesterday I purchased 3 more quarts and added another quart to the pool. I simply poured it into the pool this time, brushed the walls, steps and floor and let the filter run all afternoon. I decided to be more patient this time and give it a chance to work overnight before adding a second quart. As of this morning the stains are gone and the pool looks great again.

    It does not seem to have effected my test results nearly as much as the first use but I only used half as much this time. This morning my pH appears to have dropped to 7.0 from yesterday's 7.4 reading. Chlorine remained fairly stable with about a 3ppm drop from yesterday which is about the norm for the pool. We had a decent amount of rain last night (2") so that may have factored in as well. I have been successful at reducing my TA from 90 to 60 over the past few weeks and this seems to be keeping the pool at a pH of about 7.4 I will keep adding the recommended 4oz and see if it keeps the stains away. If not, I will attempt to lower the pH and alkalinity a tad more.

    So far, the HTH Metal Control does a good job at removing stains in my pool. This was my first time using a metal control product and it seems to work well...it is inexpensive, convenient (I grocery shop at Wal Mart) and keeps me away from the pool store!

    I haven't posted much even though I have been reading/lurking on this site for a long time. I was seriously "pool stored" with my last pool so thanks to everyone at TFP for keeping me away from the pool store and keeping my money in MY pocket
    Matt

    10,000g "Antigua" (kidney shape) fiberglass IG pool, 1 hp Hayward Super Pump, Hayward 1200 Cart filter, 130K BTU heater, Savi Melody lights.

  3. Back To Top    #3

    Re: Iron Staining and HTH Metal Control

    What does the pool look like before you put the HTH Metal Control in? Is it tinged green? I have a slightly green pool that the pool guy swears is from my stained plaster. That doesn't sound right to me. He said the water is balanced perfectly and there is no algae. So I'm thinking maybe it's the iron in the water.
    GreyBeard

    27,600 Gal, 42x16 Irregular-shaped IG Plaster,
    Hayward Superpump 3/4HP pump,
    Hayward Pro Series High Rate Sand Filter

  4. Back To Top    #4
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,347

    Re: Iron Staining and HTH Metal Control

    with the metal sequestrant you'll have to use maintenance doses of it according to the package recommendations. If you miss a dose, aas you've already seen, the stains will come back. It also affects the chlorine usage a bit but not nearly as much with the maintenance doses as with the initial dose.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    frustratedpoolmom's Avatar
    Join Date
    May 2007
    Location
    SWSuburban Chicago, IL
    Posts
    11,965

    Re: Iron Staining and HTH Metal Control

    Quote Originally Posted by Yonkers
    What does the pool look like before you put the HTH Metal Control in? Is it tinged green? I have a slightly green pool that the pool guy swears is from my stained plaster. That doesn't sound right to me. He said the water is balanced perfectly and there is no algae. So I'm thinking maybe it's the iron in the water.
    If you start a new topic, and post a full set of results, we can delve into your issue further if you like.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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