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Bob999
07-23-2009, 06:02 AM
I have a backwashing acid neutralizer with a 12 x 48 tank.

My question is how much Calcite media should be maintained in the tank?

Gary Slusser
07-23-2009, 02:56 PM
You should add mineral when the treated water pH starts going below 7.0 at high flow rates.

Bob999
07-24-2009, 05:55 AM
A 12 x 48 inch tank will have 2 cuft (or about 200 lbs) of calcite in it. It will have about 20 pounds of gravel at the base.

The tank should be about 2/3 full or a minimum of 24" bed depth. Is it mixed with corosex or just calcite. What is your raw pH?

Andy Christensen

The media is Calcite, no corosex. The raw pH is 6.5.

Bob999
07-24-2009, 12:25 PM
Yew, the Calcite alone would work fine. I suppose your pH raises to around 7.3-.4? Can you desribe your water usage. # of people, baths, plumbing diameter before and after the filter. Have you tested for hardness before and after?

Andy

I suppose your pH raises to around 7.3-.4? --It depends on flow rate. At high flow rates it will drop to 7.2 or less while at low flow rates it will be 7.8-8.0,
2 people in home, 4.5 baths, 1" plumbing in to AN filter and out to softener. Welll produces 30 gpm and pump produces 25 gpm. Hardness goes from about 5 gpg raw to 7-8 gpg after AN filter.

pH characteristic of water is that it measures acidic immediately after being drawn but if allowed to sit for a day the pH will rise to above 7--perhaps as high as 7.5.

99k
07-24-2009, 05:30 PM
The minimum will be up for debate, however, the maximum level of calcite should provide a clearance of 18" or greater from the control head.

Gary Slusser
07-25-2009, 10:24 AM
I've never seen 'calcite' alone raise pH to more than 7.3 or so.

I still say the time to add more mineral is when the max peak demand flow rate shows a pH of 7.0 or less.

99K, you say that is debatable, when would you suggest Bob999 adds mineral?

Gary Slusser
07-26-2009, 01:10 PM
IMO most if not all homeowners will have a tough time getting an accurate CO2 test.

If a bed needs to be replaced, I 'd say there was insufficient backwashing but the question was when to add more mineral.

Bob999
07-26-2009, 04:59 PM
A properly sized neutralizer should have to be filled once a year to the correct level. Most neutralizers need a re bed every 2 years.

wellexpert

I already have my AN tank and I am commited to filling it as needed.

So--What is the "correct level" to which the AN should be filled?

Why do "Most neutralizers need a re bed every 2 years." and how do I tell if my filter needs a rebed?

Gary Slusser
07-26-2009, 08:24 PM
I've sold many AN filters over the last 22 years and I've never had a customer have a problem with channeling, probably because the backwash is done properly and frequently enough to prevent channeling. Backwashing is the only way to cure channeling.

That will also prevent "impurities" from getting down in the bed. But what are these impurities actually?

Bob999
07-27-2009, 05:33 AM
I've sold many AN filters over the last 22 years and I've never had a customer have a problem with channeling, probably because the backwash is done properly and frequently enough to prevent channeling. Backwashing is the only way to cure channeling.

That will also prevent "impurities" from getting down in the bed. But what are these impurities actually?

Gary,

What do you recommend for backwashing my AN filter? It is a 12 x 48 tank, media is calcite only, and the DLFC is 7 gpm.

Gary Slusser
07-27-2009, 07:07 AM
Depending on how many people and any iron, backwash it every 3-4 days. Two people no iron, 4-6 days.

The 7 gpm may be too small.

What brand and model control valve are you using?

Bob999
07-27-2009, 07:19 AM
Depending on how many people and any iron, backwash it every 3-4 days. Two people no iron, 4-6 days.

The 7 gpm may be too small.

What brand and model control valve are you using?

The control valve is a ProFloSE. As best I can determine 7gpm is the largest flow button available for my configuration (5/8" OD for the flow control button). I have very small amounts of iron (0.1 mg/l) and manganese (0.16 mg/l). 2 people in home.

How long should the backwash and rinse be?

Gary Slusser
07-27-2009, 07:52 AM
I'd go 14-16 minutes if one backwash and then 6-8 minutes rinse. If two backwashes 6-8 and then 6-8 again and 6-8 rinse.

You could do away with the DLFC button and get a 10 gpm Dole flow control. But that's not necessary for a 2.0 cuft. And actually, you could have used a 1.5' and got a deeper bed depth, and a top dome hole type tank. IIRC 2.0' doesn't come with a TDH tank right? And a 12" x 48" doesn't get the proper freeboard area; I use 12 x 52" tanks but not for AN filters. You need bed depth, not a wider column.

Bob999
07-27-2009, 10:36 AM
IIRC 2.0' doesn't come with a TDH tank right? You need bed depth, not a wider column.

The 12 x 48 tank I have does have a top dome hole--it is a Structural Brand tank.

Thanks for the advice on the backwash.

Gary Slusser
07-27-2009, 10:41 AM
I can never remember about the 2.0' tanks.

You're welcome.

Bob999
07-27-2009, 03:22 PM
I'd go 14-16 minutes if one backwash and then 6-8 minutes rinse. If two backwashes 6-8 and then 6-8 again and 6-8 rinse.



Is your recommendation that this backwash/rinse be done every 3 to 4 days because of the iron (0.1 mg/l) and manganese (0.16 mg/l) in my water?

Gary Slusser
07-27-2009, 04:46 PM
Based on what you have said so far you could.

shas
05-24-2010, 02:47 PM
I need to add a couple 50 lb bags of Calcite to my system. What do I need to know about backwashing? I'm not sure how to do it -- don't recall if the installer ever mentioned it. I don't believe I have an automatic system. I have a top-flow tank with no electronic controls at the top. Other than shutting valves and funneling in the bags, what do I need to know about backwashing? Thanks in advance.

Gary Slusser
05-27-2010, 11:40 AM
You have an upflow filter meaning there is no control valve so the water goes down the distributor tube and up through the mineral and out to the fixtures. So you need to run water somewhere other than in a septic tank to get rid of any discolored water after refilling the tank with new mineral.