Any particular reason you use dry acid vs muriatic acid? MA is cheaper and has no sulfate build up.
Inorganic stains...ugh!
- Thread starter C3Cl3N3O3
- Start date
I've used both. I guess I'm not up to speed on the sulfate issue. The previous owner left me a 20 lb tub of dry acid, so I've been using it up. I've only been doing BBB for 2 years or so. In the past I just kept the pH at the high side, 7.8. So it didn't take much acid to keep it there. However in light of this metal issue, 7.8 probably isn't the ideal pH setpoint for my pool. But 7.2 is going to be onerous.
- Mar 24, 2014
- 2,455
- Pool Size
- 32000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool SJ-55
MA is STRONG. With a 20k gallon pool it won't take much to get it as low as you want. I always recommend taking baby steps, shoot for 7.5 or so at first, it's very easy to over shoot pH adjustments.
Using up the dry acid you have isn't a big problem. It is probably worth trying PH at a higher level to see how it impacts the staining and then creep up or down a little at a time to see how it goes. Not all pools react the same way.
So just to be naughty I transitioned to the mystery sequestrant in this thread a few days ago when the pool started to turn (I had another 32 ounces that I didn't return). It's all I had on hand. So that reversed the stair yellowing issue, and caused more precipitation than the Metal Free. I've been doing a week's worth of maintenance doses (7 - 10 oz) each day and then vacuuming. Today, there wasn't much precipitation. That may or may not be an indicator of anything, or perhaps I've turned a corner? The water is still blue and the stairs are white. I'll transition again to Jack Magic's on Thu/Fri. If one sequestrant is good, then three sequestrants must be three times as good, right? 
Well on the bright side you now have direct experience on two of the non-recommended sequestrants and some interesting details about their behavior If they're actually precipitating metals then its a good thing.
If they're actually precipitating metals then its a good thing.
LOL! Well, it is your pool so you are in charge. Metals are a bit of a mystery and act differently in different pools. If there is one place where some experimentation is good it is in dealing with metals. Keep some notes on what works and what doesn't and help some other folks with their metal issues. And definitely keep reporting your results so we can learn too.
Metals are a bit of a mystery and act differently in different pools. If there is one place where some experimentation is good it is in dealing with metals. Keep some notes on what works and what doesn't and help some other folks with their metal issues. And definitely keep reporting your results so we can learn too.
Yeah it's too bad the Oasis sequestrant has mysterious ingredients. Oasis is unique to Charlotte, but I'm sure that product is just something they rebrand. Maybe those NJTSRN numbers will show up again somewhere else. In the case of my pool it seems to show some efficacy.
So my limited knowledge thus far tells me there is "good precipitation" of metals combined with sequestrant in the form of debris which can be easily vacuumed out, and "bad precipitation" that is basically just metals forming stubborn liner stains which can't be brushed off. Perhaps the same water chemistry is conducive to both forming? In my case, the precipitation became more substantial after I let the pH float up (about 7.6) and increased the FC (7 - 8). So maybe you have to be on the bleeding edge but with adequate sequestrant (perhaps non-HEDP) to get the "good precipitation", and if you aggressively keep pH and FC low with a more powerful HEDP sequestrant you'll never see it?
So my chlorine demand is down to 4 ppm per day, which is still elevated but manageable.
So my limited knowledge thus far tells me there is "good precipitation" of metals combined with sequestrant in the form of debris which can be easily vacuumed out, and "bad precipitation" that is basically just metals forming stubborn liner stains which can't be brushed off. Perhaps the same water chemistry is conducive to both forming? In my case, the precipitation became more substantial after I let the pH float up (about 7.6) and increased the FC (7 - 8). So maybe you have to be on the bleeding edge but with adequate sequestrant (perhaps non-HEDP) to get the "good precipitation", and if you aggressively keep pH and FC low with a more powerful HEDP sequestrant you'll never see it?
So my chlorine demand is down to 4 ppm per day, which is still elevated but manageable.
I'll reevaluate in a week or so. It's been closer to 2 ppm/day in past years. I may have to float the CYA up to 60 or so.
So after charging my sand filter with DE a week ago, it has picked up 1 PSI. That is actually a lot for my filter. If there are metals in there, it's unclear to me if they are completely stable salts, or if they can break down again from chlorine. Not wanting to risk that, I backwashed it and recharged it with DE. So whatever that was is gone.
So after charging my sand filter with DE a week ago, it has picked up 1 PSI. That is actually a lot for my filter. If there are metals in there, it's unclear to me if they are completely stable salts, or if they can break down again from chlorine. Not wanting to risk that, I backwashed it and recharged it with DE. So whatever that was is gone.
So the greenish hue, I don't know. I don't think my earlier reports are reliable. I've been watching the water closely today and the perceived water color can change slightly based upon the elevation, angle of the sun, cloud cover, etc. So I don't think the sequestrant "fixed" any greenish hue.
But REALLY green water, you know when you have that. I don't have that. Still crystal clear and no metal precipitation today.
But REALLY green water, you know when you have that. I don't have that. Still crystal clear and no metal precipitation today.
OK so the water is definitely bluer today lol.
One interesting development, my sand filter mysteriously picked up 2 PSI overnight. I hadn't seen that in the past week since starting the DE. Interesting. I went ahead and backwashed it.
One interesting development, my sand filter mysteriously picked up 2 PSI overnight. I hadn't seen that in the past week since starting the DE. Interesting. I went ahead and backwashed it.
My sand filter increases with use of sequestrant, just so you know. I backwash at 25%
So does that trail off in your case? I've backwashed three times during this process. The PSI starts off at 16, then I add the DE to bring it up to 17, and it stays there for a day or so. Then in seems to rapidly move up 2 or 3 PSI to 20. So I assume it is still picking up some metals?
So the good news is the water looks fantastic today. I think the liner has actually gotten a tad lighter in color over the past few days. The chlorine demand is down to 2 ppm/day. There's no green at all, just a perfect light blue. So I think that greenish hue is an indicator of an issue. So I'll have to monitor that. The stairs have remained white, that's another canary in the coal mine indicator to monitor. I have the Jack's Magic but have not used it yet.
Thanks to everyone who contributed on this thread, here's the obligatory after shot!
Well I'm hanging in there. I'm using about 16 oz / week maintenance dose of Jacks' Magic Vinyl Liner Blue Stuff. The downside of that of course is that is going to run me about $50 a month. I really need to find a long term solution here.