Iron staining that won't end

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L

LSxBrad

0
Aug 5, 2017
10
Metro Detroit, MI
Have a pool/house that is new to me this year. I am on well water that has 4.0ppm iron, but the water goes through a backwashing whole house iron reduction system, that takes it down to about .5ppm. My softener takes care of the rest for in house use, but the pool gets filled with the .5ppm iron water. I have a 1.0 micron filter at the end of the hose, that does catch some iron oxide.

That .5ppm iron is obviously enough to cause me grief with the pool. I have had to do AA treatments multiple times this year. It usually removes 95% of the staining over night (add about 1lb). I then backwash my filter and dose the pool with a sequestrant. I still can't seem to keep the staining at bay. It eventually comes back, even though I add either Pro Team Metal Magic or Jack's Magic Pink Stuff.

Pool specs:
7500 gallon Jacuzzi fiberglass
1 hp Pentair pump
40 gpm sand filter

Here are my water tests that I came up with using a Taylor K2006:
pH 7.2
FC 0.0 (lowered for AA treatment) but normally kept around 5.0
TA 100
CH 300
CYA 70 (don't know why it is still so high as I've replaced over 50% of the water this year and I primarily use 12% bleach)
Depending on water temp, this puts my CSI around -0.2.

My numbers were way out of line earlier this year. I've spent a lot of time getting them where they are now. pH, TA, CH, and CYA were all significantly higher when I started. The previous owner used only cal-hypo and trichlor.

Am I missing anything that could be causing my repeated issues? I've found that if I let the pH get into the high 7s and FC to 10, the staining is almost guaranteed. I am in the middle of another AA treatment this weekend, and it just isn't working very well for some reason. I'm at the end of my rope with this thing. Any help would be appreciated. Local pool stores had me running in circles, until I found this site, and bought a real test kit.

Thx
 
Good morning, LSxBrad. Welcome to TFP.

Well, you're already doing pretty much what I'm doing, but let me see if I can come up with anything to try ;) You're brand new to TFP, and at the same time, are struggling with an advanced topic...so some of my suggestions toward the bottom will be a little on the experimental side ;) I'm assuming you're normally familiar with [fc/cya][/FC/cya] and TFP treatment methods, where you do always control ph anyway. Also, just so you know, AA and even metal magic can be applied directly to stains if you have trouble areas.

First off, regarding the CYA, is there now or was there ever a SWG?

If not, and if the CYA was just incredibly high before, the easiest way to get some respite on your metal management program may well be to start with a partial drain to get both the CYA and iron down to a more manageable level. By lowering the cya, you can keep te FC at a lower level.

I'm in GR, and when I did a liner change last year, 24,000 gallons cost me $1,000, but at 7500 gallons, yours for a partial wouldn't even be a full truckload.

By diluting the concentration, which I suspect has built up over time, you will find the sequestrant lasts a good deal longer.

A second "right now" kind of thing is to try extra Metal Magic as same can work decently on stains. By doing the http://www.proteampoolcare.com/images/uploads/MetalMagicSpongeTest.pdf you might at least be able to get off th AA cycle. I stopped doing AA a few years back in favor of straight MM treatment at high dose, which solved 3 problems for me...didn't have the hassle of AA, needed sequestrant anyway, and also was easier to use because you use it at ph of 7.6. And its cheaper...

But longer term, .5 ppm at source is def problematic on a few fronts. Here are a couple of thoughts:

1. Softener - upgrade to dual: One thing that happens when using softened water to top up is that you can end up putting raw well water in because it taps out before scheduled regeneration. This happened to me, and I was also getting higher ppm out of it as I suspect the resin bed was fouled and not removing as much iron. I switched to dual softener system, which reduced my ppm much better and ensured I didn't tap out during a top up. But my top ups take many more gallons than yours, so this may or ay not make a real difference.

2. Consider an air injection softener upgrade...I know you already have an iron curtain style system prior to the softener, but I'm wondering if a second air injection system would help on the final output. That would oxidize more for filtration on output.

3. Consider a magnesium sand prefilter...I haven't ended up needing this and posters here have reported mixed results, but in your case a Metal Trap green sand prefilter on the pool might be a worthwhile investment. They're pricier but with a known finished level of .5 ppm and a well at 4 ppm, it might be worth it just in reduction of sequestrant needed.

4. VERY EXPERIMENTAL and best reserved for close or opening: with your source at .5 ppm, your accumulation rate is going to be problematic.

Short of water change, there are two other known ways to possibly remove iron:
1. Oxidize the metal by shocking and set up a filtration loop with either a Polyfill DIY bucket, hose and pump OR set up a 10" Pentak with reducing 25:1 micron filter.

- Downside is you may stain doing this, but Metal Magic should remove and sequester after treatment if you use a high enough volume.

2. Alum Floc, Leslie's brand specifically -- TFP does not advocate using floc, which is tricky, for anything because it masks other problems etc.

But as an iron treatment, it may hold some promise. With a floc treatment, all the parameters for use have to be just right to get it to drop, and you must be able to vac to waste (since you have a sand filter you should be able to use it). I plan to try one this fall and can keep you posted if you'd like me to be the guinea pig ;)

I am highly distracted at the moment as have entire oot family awaking from family campout here, so gotta run. I will try to check back in when thing quiet down.
 
SW- Thank you for your in depth reply. I have read some of your previous posts about iron issues. I'm at the office right now, so I only had a chance to glance over what you wrote. I will read it more in depth this evening. I'm coming off another AA treatment, and it looks like the staining is gone again, and the cloudiness is clearing. I'm going to try dosing it heavily with Metal Magic, before anything has a chance to precipitate out again, as I develop a more long term solution.

I also meant to add that I'm running 5 micron filter bags on my return jets during the AA process, and usually after larger top offs. They do catch some rust and other white residue, so they appear to be helping some. I've been a city water guy my whole life, so this well situation has been something new for me (for both drinking water and pool water). The water was basically undrinkable before I installed the iron curtain, along with an RO system for the kitchen tap water. I don't know how the previous owners could even tolerate it. Most of the plumbing fixtures/washer/dish washer were destroyed by the iron laden water. I don't think I'll ever complain about a city water bill again :)

Is the Alum floc process similar to using Poly Aluminum Chloride? I stumbled onto a large thread about using that to oxidize and filter out iron, even though it is marketed to remove phosphates. That was going to be my next step, as I know I need to try something different. Can't keep doing the same thing, expecting different results...Isn't that the definition of insanity?

Enjoy your family time, and thanks again.
 
Lol. NOW you're wading into the deep end, and possibly with someone less-than-qualified. I'm hopeful Joyful Noise will pop by with some coherent intel.

Here's what I "think" I know about PACs (poly aluminum chloride)...I've generally had the impression they're even more unreliable at producing the "dropped floc" than alum, whch is pure aluminum sulphide.

But since TFP generally avoids all floc discussion, I've not been able to glean much or sort out whether this impression is misinformed or not. Comparatively, ive had a convo with a poster who works in water treatment who comfortably flocs with Alum each year for both iron AND phosphate removal. Likewise several poster in Europe, where alum floc is the go-to for metal reduction.

By way of explanation on the phosphate removal angle, heavy sequestrant users also build up high orthophosphate levels from degraded diphosphonic products. Not necessarily a big deal, as TFP levels will ensure those high levels are meaningless in terms of algae, but since I am swg and run my water hot, I was wanting to avoid the semi-remote possibility of phosphate scale on my cell or exchanger. Hence te exploration of the topic.

Since we're still on experimental topics...A few years back I'd run across something called FerriTabs that The Pool Guy in Brighton MI sells (Leisure Pools, I think?)
They are polyacrylamide...similar idea to PAC.

In my sequestered water, they did not do anything...but I suspect they do something in tinted water where iron is oxidized. I had messed up my experiment with them, in essence, but this poster did not, so have a read: Ferri-Tabs Review - Page 2

In the mean time, I'll see if I can dig up anything remotely authorative on PACs ;)
 
Thanks again for your input. The good news is, I have been stain free for over a week now. I initially dosed the water with 32oz of Jack's Magic Pink, and just added 16 oz more this weekend, as I brought my chlorine levels back up to normal. I've been hesitant to raise it, since that usually results in heavy staining. FC is now in the 7-10 range. Fingers crossed. I figure I only have about another month for the season, and want to avoid doing too much before I have to winterize. I will report back again this coming weekend.
 
I've been staying quiet and watching your progress but I just wanted to offer my experience.
First, here is a picture of what my pool looked like.

Trouble Free Pool

I had decided to take the Zen approach and enjoy the ever changing pattern of spots and stripes. Since it's just a stain and in no way effects the function of the pool. But with some prodding from a few folks I decided to try a few experiments. One friendly poster suggested Metal Magic by ProTeam. It can be had fairly cheaply on Amazon from a seller named Pool Geek. (not poolgeek) My pool is only around 4800 gals so I initial dosed with 16ozs. Within half a day it was here:

Trouble Free Pool

After 24 hours: (opposite view)

Trouble Free Pool

Now that Metal Magic is back in stock, I bought a 4 pack and have been dosing at 2 ozs each time I start to notice any staining at all. Usually about 2 weeks. It's takes care of it in less than a day.

Note: I do nothing with my FC, pH or any other parameters. I don't even change my pump run times. Have not measured any FC drop with the use of Metal Magic.
 
pabeader-Unfortunately, I can't see your attachments...it says "invalid". Thanks for your input. Sounds like you and SW have had the same luck with sequestrants.

My staining is starting to return again, now that the chlorine is back up to a "normal" range for my CYA. Seems to happen every time. I'm going to try to add more Metal Magic this week, to see if the minor stains will release without an AA treatment.

Checked my chemistry again last night and here is what I got:
FC-6
CC-<.5
pH-7.4 (was 6.8 the day before, so I aerated)
TA-115
CH-150 which is very surprising since it has been about 300 for the last month or so. Does phosphonic acid sequester calcium also? The fill water is fairly hard and is about 300-350 when tested raw.

I'm also starting to wonder if my filter sand is fouled with rust, and should be changed out. It was changed last year by the previous owner, and they stated they had no staining issues whatsoever. Any thoughts?
 
The first time you backwash I would think any 'rust' would be cleared out.

Yes, some sequesters will effect calcium. It doesn't always happen so we don't use it a recommended item for calcium reduction.

Weird about the images. Will work on that.
 

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LSxBrad, what kind of surface does you pool have again? Maybe add those details to your signature for quick reference ;)

Generally, sequestrants work better if CH is kept around 200 (higher for gunite) even on a vinyl pool.

But metals can interfere with the ch reading. Make sure you go beyond "purple tint" and keep adding drops til its actually blue tint, not purple. Subtract the last drop that made no change.

While the sequestrant may have bound up some ch, its unlikely to ave halved it, so I'm suspicious that you're getting test interference.
 
SW- Pool is fiberglass, but the finish isn't very smooth, even when there is no staining. If it were a boat, i would wet sand and polish it. I actually did a second CH test, and had the same results. I also keep getting white stuff coming off of the walls, when I brush it. No idea what it is. I was assuming it was calcium that precipitated out, but it could just be some oxidized gel coat coming off?

Staining was back again this weekend, so I did an AA treatment. Pool cleared up within 30 minutes. Today, I am draining it, and refilling it with my softened water (replumbed my outdoor spigot to soft water). I think I just have too much iron content in the water, and the pool is small enough, that refilling it isn't a huge deal. If it were larger, I may have tried the "oxidation" route, to see if it works. Should be able to have it filled by tomorrow evening. Going to break it up into 2-3 batches, to allow the softener and iron filter to regenerate. Will let everyone know how it goes.
 
Was able to wet sand about 90% of the surface, but didn't go as fine as 1000 grit. Patience was wearing thin. I can't believe how much more smooth it is now though. Previously, it has the texture of skin. I'm not sure if it is the chlorine or the UV rays damaging the surface.

It is about 1/3 of the way filled again, with softened water. I will do another 1/3 today, and the final 1/3 tomorrow. This gives my iron filter and water softener time to regenerate. I also hooked two 10" filter canisters to my fill water. One has small pieces of chlorine tablets in it right at the spigot, and another that has a 1 micron filter, 50' downstream. My hopes were that the chlorine would oxidize any residual iron, and the filter could then catch it. It appears to be working, as the filter is turning orange. The chlorine will probably ruin the hose, but if it helps remove any iron at all, it will be worth it. I'm coming to the realization that anything you can do to PREVENT iron from getting in your pool water is worth it. As the saying goes, an ounce of prevention is worth a pound of cure.

I also found a few rusty stainless steel screws in my light housing. Not only were they rusty, but they also looked like some electrolysis was happening there as well. The light is non functioning anyway, so I just removed it for now, and turned off the circuit breaker to it. I will install a new one next year.
 
I don't think it's surface damage, I truly believe it's calcium scale. At least when I did mine, it made the pool go slightly milky for a few days until the filter was able to pick it up. But it's so fine, it's hard to tell for sure.
 
I like this idea...
One has small pieces of chlorine tablets in it right at the spigot, and another that has a 1 micron filter, 50' downstream. My hopes were that the chlorine would oxidize any residual iron, and the filter could then catch it. It appears to be working, as the filter is turning orange
Click to expand...
it might work even better on a 2-stage pre-filter, one with the puck piece, one without...just make sure if the water coming out is highly FC concentrated that you're aiming for the deep end/have water moving if possible. Then again, puck chlorinators do this all the time...
 
I filled the pool in 3 stages. The first stage, I noticed some rust being caught in the hose end filter, as I mentioned earlier, which I just assumed was iron slipping through my well system. I regenerated both my iron filter and my water softener that night, and started filling again the next morning with a brand new hose end filter element, using my same setup. The filter never turned red again. I let it fill the second 1/3 of the way, and regenerated everything again that night. Again, I resumed filling the next day. Same thing, no rust. That indicated to me that there was little to no iron making it through my well system. I can't figure out why that wasn't the case on the first day. I even used a brand new hose, to eliminate that as a possible source of iron. This continues to be more a mystery, than a learning experience.

Anyway, I have the pool completely filled, and don't have any staining yet. I haven't added any Pink Stuff or Metal Magic, as I wanted to see what was going to happen. I do have my 5 micron filter bags on the return jets, and they did catch a small amount of oxidized iron. I'm running the chlorine at about 7, just to see if I could get anything oxidized, and filtered out, before it had time to stick to the pool surface. I need to get the water balanced this weekend. My TA is VERY high, CH is VERY low, and my CYA is 0. pH is about 7.2, which is what the well water is coming out of the hose. I have to boost the pH of the well water going to the pressure tank with soda ash, so the iron filter will work more effectively. I'm guessing that is where my high TA is coming from. As long as I don't get any staining, balancing the water should be fairly straightforward. Since I do use some stabilized chlorine pucks at times, I'm not sure how much "stabilizer" I want to add. I know I need to have some CYA level, but it was so high before, I want to be careful. Pool Math says about 30oz to go from 0 to 30, which is the minimum recommended. I supposed I could start low, and see what the chlorine demand is throughout the day, and adjust from there.
 

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