Ok, right, it's greensand that uses the permanganate. Filox looked to be the most efficient stuff out there without pre-oxidation although getting a handle on expected performance is not easy. I've seen numbers from 5-15 ppm iron removal capacity for these systems. Does anyone have any reliable, real-world numbers that I could expect for the various filter media (BIRM, MnO2) assuming the following parameters:
Backwash 8.5 GPM
no iron bacteria
My softener can pick-up some clear water iron bleed-thru (4 ppm ?)
Where does the 8.5 gpm come from?
And how do you know you only need a 1.0 cuft? That will give you a SFR of about 4 gpm and a 1 bath house can exceed that very easily.
You would be better off with a chlorination system but I don't like using the pressure tank as part of the retention. I don't like solution feeders either. A dry pellet chlorinator and a special mixing tank is the best choice.
I will agree with that post.
I measured the time it takes to recharge my well tank (39 sec) and then the gallons delivered before the pump kicks in again (5.5). 5.5/39x60=8.46 Is that the correct method? The 1 cuft was based on backwash recommended flow rates for a 9" tank.
The best way is with a device that actually measures gpm at the average pressure the system is run at by lifting the pump drop pipe up out of the ground and measuring there or, to know the static water level in the well, the gpm rating of the pump and the depth the pump is in the well and what ID the pipe is to the pressure tank and the size of the piping on the pressure tank and to the filter.
Otherwise you run water into a bucket while refilling the pressure tank and actually measure the gpm you get realizing you are usually flowing through a 1/2 or 3/4" boiler drain valve on the pressure tank and maybe some 3/4" stuff on the pressure tank/plumbing.
And again, a 1.0 cuft is more than likely much too small to provide the peak demand gpm the house requires; based on how you use water like a couple showers running at the same time or a shower and washing machine or dish washer or toilet flushes etc..
The required gpm of the backwash is based on the cu ft volume and the type of mineral being used; not the size of the tank. The size of the tank is dictated by the cu ft volume and type of mineral/media being used. The size of the tank then dictates the control valve that can be used.
When the filter is in backwash there is little flow resistance in the plumbing to the control valve, unlike when refilling the tank as you did and using time. The captive air pressure in the pressure tank and possibly smaller ID pipe than the 1" you should use all the way to the filter control valve. That air pressure and possibly smaller ID pipe reduction reduces flow.
Had a Kinetico rep out to the house today, very nice and knowledgable fellow. He got similar results, ~11 ppm total iron untreated and 6 ppm after the softener. Unfortunately he said the remaining iron was colloidal and said he wouldn't even try to sell me one of their units. Given the relatively sudden change in my well and the fact that it fluctuates he suspects the well pipe might have a hole in it. I take it the only way to get at that stuff is with chlorination but I am going to get the well checked first before proceeding. Thanks for the help and suggestions.
I would be interested in how he determined it was colloidal...? did he use a mini-softener for his testing. Colloidal and bacterial irons are different. Chlorination can take care of bacterial types but colloidal may need membrane technology or some kind of flocculation/coagulation method. Colloidal is extremely rare in my area, so fortunately I don't to mess with it. But in areas where it exists, it can be a daunting task and never cheap and easy. Since it has the specific gravity of water, colloidal iron won't settle to bottom of glass and should be visible straight from then tap.
Be very sure what you are dealing with before buying. It is better that he walked away than throw a "try-it-out-and-see solution" at you.
---did you see a "mermaid"?
Yeah, he said it was rare too and he'd only seen it a few times but this looked exactly like what he'd seen in the past. I think it fluctuates with rainfall (I'm now keeping a log) but when it's bad like it was this morning the water out of the kitchen tap is immediately reddish/brown and particles do not settle out. I showed him a two day old sample bottle and the color was exactly the same. He did say there were coagulants that could be used but in his experience digging a deeper well is the only solution assuming the problem is due to shallow well and/or a breach in the well casing.
I called up the original well driller and the depth of the well is 455'. They said my problem is consistent with wells of this age (25 years) and galvanized steel rusting over time and getting pinholes in the threaded section joints. She did say I could try a shock chlorination but there was a chance it would ruin the pump and in any case that would only be a short term solution. Looks like a new well for me.
I would not shock a well with galvanized casing. Chlorine and galvanized do not get along well.
What problems would you expect? I was thinking of doing just a single chlorination (after the holidays) to see if it cleared things up and for how long.
Chlorine attacks steel and steel that is already rusted bad is going to cause some very rusty water for possibly days or weeks. And then the fresh water can rust the steel more. If you were to 'surge' the well to clean the rust out as you chlorinated, that might help.
On the other hand if you shock the well, what do you have to lose?