Iron and sequestrants in spa

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Kidneydoc

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Aug 29, 2013
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Vero Beach, FL
So I filled the new spa today from my well water and I have that nice clear yellow iron color. I am going to have my water guy install a Penteck DGD-2501 dual gradient filter in a big blue housing so I can use this set up for my every 3 month water changes. In the mean time, any harm in using metal sequestrants? I understand they don't remove the iron long term (...a concern for a pool), but I only need a short term solution (2-3 months) before I dump the water and start over. Thanks.

Also, any health risks or skin reactions common with sequestrants? I could not find any data on this. Thanks again.
 
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The latest in my new Spa drama...My well water treatment guy tested our water and yup, has lot of iron. Our softener/peroxide system does a good job cleaning up the water for house use. He suggests we upgrade our water system for two tanks (so one fills while the other recharges), and that will allow me to fill my 1200 gallon spa without interruption at will. (just recharge the brine salt...easy move).

So using "soft" water for spa....I know I will have to re-add Calcium to get the CH up to some value (150-250 ish)....the question is, other than adding calcium, any issues with using soft water for spa filling?

Thanks!
 
Kidneydoc said:
So using "soft" water for spa....I know I will have to re-add Calcium to get the CH up to some value (150-250 ish)....the question is, other than adding calcium, any issues with using soft water for spa filling?
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A vinyl/fiberglass/acrylic pool/spa does not need calcium. Does Swimspa specify a minimum CH requirement?
 
Kidneydoc said:
I though CH is needed to prevent foaming in spa?
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I would see how if you have foaming with your fill water. If you do then raise it 50 ppm at a time until you find the level that works for you. Some folks are fine with 75 or 100 or 150 ppm of CH in their spa.
 
OK...update....spa filled with high iron and high tannin well water. I SLAMed it (...kinda over did it...FC>20). About 48-72 hours later with cover off, the water went from brown/tea colored/cloudy to now crystal clear. Only issue is iron colored ring around edge of spa (easily reomved with rag).

So, I guess the chlorine was able to oxadzize all the orgnics of the tannins and the paper filter ? pullout out much of the iron. I need to go wash out the filters now. So, perhaps I can continue with well water for future fills. When FC drops some, I suppose I can sequester some of the iron so it ? doesn't keep staining and/or ? depositing in the heater (...not sure if this an issue). Yes, sequestrants cost some $, but it will cost me $3000-$4000 for an upgrade to my water softener system to be able to fill the spa with soft water.

The other issue is the TA was 250-300+ from the well, so every day, or even 2X a day, I am adding HCL to push down pH to 7-ish and lower TA. I am down to about 120s now....but acid cheap as well. When TA down to 50, I will add Borax (liquid balanced form) for pH stabilization, soft feel to water, etc. I will also add salt to pool for my Saltron mini as well.

If i fill with soft water (beside the up front cost of upgrading my home water softener system), I would then have to add CH to each fill.

I suppose I can also try the Metal Filter with next fill (from well) and perhaps that will help minimize the problem.

Just looking for any thoughts on this set up.

I still may upgrade my home system for other reasons (....during recharge of the softener, the system allows untreated water into the house...usually at night, but there are some sinks and toilets that get iron rings if used at night). A new system would prevent this. But from hot tub perspective, perhaps I can live with this SLAM when fill and wait a few days method.

Any thoughts on this issue appreciated.
 

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I had foaming and targeted CH around 150, but stopped at 140 pool store numbers (jived by weight...). Found a white powdery film on filter housing float and inside housing. Probably coated heater element the same way.

I don't think there's a "formula" for when calcium will precipitate, so recommend doing without until needed, then adding in small amounts until foaming "level" is acceptable.

For me, issues began 2 months in. If I was $$$$ I suppose I could've dumped it... I think it calculated to $20 (less cost of calcium), so about $80 a year to dump every 2 months. Mine's 515 gallons, so yours is about double?

There was a thread about water clarity I recall. The OP was obsessed with getting back that fresh fill sparkle. He tried tons of stuff because he didn't want to dump it even though the water had already gone a decent span. Overwhelming advice was dump.

Long story short, he got his sparkle back. He used a clarifier and filter cleaning (dont recall if it took multiple cycles). I'm SURE dumping would have been cheaper, especially if you factor in time - but the two takeaways for me were 1) put as little into your tub as possible (IIRC his issue was self-inflicted), and 2) maybe you can solve any issue if willing to go to war over it, but dumping it is an immediate, decisive win with a FIXED cost.

Sorry about being preachy, obviously you are thinking through all the issues 🙂
 
Update:
I chose to upgrage well water softener system so I have constant supply and i will fill spa with softened water. This will elimiate tannins and visual iron issues. I also found a link somewhere in TFP for Duda Energy web site for very cheap borax (instead of Spa Gentle borax) and it is supposed to be less pH altering. But even if it is not, very easy to add acid if needed. Thanks for all input!
 
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Kidneydoc said:
Update:
I chose to upgrage well water softener system so I have constant supply and i will fill spa with softened water. This will elimiate tannins and visual iron issues. I also found a link somewhere in TFP for Duda Energy web site for very cheap borax (instead of Spa Gentle borax) and it is supposed to be less pH altering. But even if it is not, very easy to add acid if needed. Thanks for all input!
Click to expand...
You want granular boric acid (not powdered) from duda diesel - not borax. With borax you must compensate with acid, you don’t have to do this with granular boric acid, just dump it in, brush it around & move on.
 
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