Sediment in calcite tank, Pls suggest debug and new design

[Chevsky]

Hi Folks,
I just discovered that my calcite neutralizer tank is clogged with sediment. Can you suggest how best to diagnose the situation, and what schematic plumbing arraignment would work best if I just have to live with sediment?

I assume that I'll need a sediment filter FIRST, then water conditioning (pH is ~5.5-6.0 without conditioning), then another filter -- probably just a simple 2-5 micron element. I'm okay setting up the first sediment filter to manually (or auto) backflush into the septic system, cuz my guess is the volume of sediment will be low enough, and this will save me the effort of plumbing a drain out to a dry well in the yard.

Here are some images. (At first I was thinking this might be algae so I didn't think to ask to test for minerals; but upon taking these photos I now believe it's mud/sand/silt). The 1st photo is the inside of the 14x54 tank. The others are the sediment that was caked on a Watts 10" filter element. I installed these 4 years ago, thinking that it would be a simple occasional filter element replacement, and 1-3 years add calcite media. The well plumbing already had two tees downstream of the pressure tank, both to ball valves with nothing on the other side, and another inline valve between the two tees. Simple to add a tank and filter. So flow is: pressure tank, calcite tank, filter, on to the house. (the filter was recommened simply to catch any calcite grains that escaped the tank; and I chose the calcite tank over soda-ash injection cus it seems much simpler, no electronics, etc.)

The first time I replaced the filter cartridge it was just dark in color, and the new/white filter seemed to get discolored within a month. The next couple times I replaced it was quite dirty, and the replacement discolored very quickly. I then let it go for 1.5 years... tho I keep noticing the filter needed replacing, I procrastinate... Until yesterday, I replaced the cartridge but noticed that as soon as I open the valves the filter fouled instantly. I back flushed into a bucket, which cleared 90% of the sediment, then went about cleaning the faucet screens (3 full baths, etc). When I saw that the filter was fouled again I realized I had a problem. By-passed the calcite tank, open the fill port, and saw it's fouled with sediment at the top. Since this is a simple non-back-flushing setup, it's upflow... So I assume the entire calcite tank is fouled from the bottom up.

Now, I don't know if the well is sending more sediment now than it was when we bought the house 6 yrs ago. At the time the water tests may not have included a sediment test. So I either have had a problem all along, or it's getting worse. For all I know the calcite (and 10% corosex) is degrading into a sediment-looking slurry! Today I sent two samples for testing -- one from the pressure tank, the other from the residual water in the calcite tank (stirred a bit to include some of the fine sediment), just asking for pH and bacteria tests.

I plan to wheel the tank out to the backyard and dump the contents. If I stay with this tank then I'll clean, sanitize, and recharge with new media. And hopefully someone can suggest a plan to diagnose, and a strategy of living with high sediment if that's all there is to it.

*The well may be 22 years old (age of house) but not sure of depth or the pump age. (there's what looks like a smaller (and abandoned) well elsewhere on the property, which might have been the first well). I sure hope this situation doesn't call for an inspection of the well, refit the pump height, etc.

Thanks!

 

[Reach4]

It is best to have a downflow calcite tank with regular backwashing. I think that should wash out sediment each period (week?). If you do put a cartridge filter first, note that the filter must be able to pass enough flow to backwash, even when the cartridge is not new. I am not a pro.

An upflow calcite tank , which I suspect you have, does not have backwashing. It would be possible to run an appropriate GPM to a drain periodically, and that would backwash.

I like the cheap electronic pH testers. My well and plumbing sanitizing write-up is at https://terrylove.com/forums/index....izing-extra-attention-to-4-inch-casing.65845/

 

[Sponsor]

 

[Bannerman]

The flow rate to effectively eliminate debris from the media and also expand, lift and reclassify calcium carbonate (calcite) is 12 GPM per square foot. For a 14" diameter tank, this calculates as 13 GPM flow up through the tank so as to expand the media only 35% with 60℉ incoming water temperature.

Since typical water flow for a residential application will usually require far less than 13 GPM, there will be minimal if any media expansion of the heavy media (90 lbs/ft3) unless a method is implemented to regularly backwash the media manually at the appropriate flow rate.

Without a regular backwash routine, calcite media can compact into a solid mass, similar to a lump of concrete. Because water will always follow the path of least resistance, channels through/around the media will often occur. As the water will follow the same path from the bottom to the top, that will often result in a less effective AN since the water will have minimal contact with the media.

If you wish to continue utilizing calcite & corosex, suggest utilizing a BackWashing control valve configured for down flow service flow.

Unless your well, pump and plumbing system upstream of the AN is capable of supporting at least 13 GPM for the entire duration of a 15-minute BackWash + 6-minute Rapid Rinse cycle, you may need to utilize a smaller diameter media tank.
Since 12 GPM/ft2 should lift the media only ~35%, there is usually little risk of media loss to drain if the backwash rate somewhat exceeds the 12 GPM/ft2 recommendation.

 

[Chevsky]

(sorry for the slow reply--I was on the road all day yesterday)

Ok, maybe the calcite tank is oversized.
The water system in on the big side -- 86-gal pressure tank, 1-1/4" main trunk, (not sure of the pump size), horse barn, gardens, so I got a large tank, even tho 98% of time it's just two of us. (Currently using conditioned water for gardens, ?)

I didn't account for sediment.

@Reach4 -- "It would be possible to run an appropriate GPM to a drain periodically, and that would backwash." -- Do you mean periodically connect a hose to the bib between the tank and my canister filter, and let-er-rip for a while to clear out the sediment? Maybe 3-5 times spring/summer/fall? (I'd like to find a fill plug with a light and camera built in!)

So seems like my options are:
1. Install [auto-flush] sediment filter upstream of the calcite tank; clean tank, replace media; Keep system as a simple non-back-washing, non-electric upflow tank.
2. Switch out the non-backwashing head for a backwashing head, downflow, insure adequate flow rate; (clean and renew tank & media). Sediment prefilter?
3. Switch out the non-backwashing tank to a smaller 10" backwashing setup; (clean and renew). Sediment prefilter?

Back-washing is meant to "clean" and loosen the media... So I guess cleaning includes sediment. I think it also includes lots of contaminants, from chemicals to dissolved metals and minerals that get strained by or precipitate onto the calcite granules. Thus back-washing takes a lot of time to complete, and thus a lot of water used in the process. But if I only have sediment, then can I drastically shorten the cleaning cycle? Maybe try to get some of the coarser sediment with an auto-flushing prefilter?

I chose the simple non-backwashing type because I thought there wasn't a problem of iron or other stuff (or sediment) at my site. This simple setup is recommended IF the are NO other issues besides pH. Oh well.

Maybe I can keep the existing tank setup if I deal with the bulk of sediment upstream(?). My cartridge filter has a valved hose bib tee'd off just upstreasm of it, which has been handy to backflush the filter. If I copy this arraignment upstream of the calcite tank, and then send the valved tee into the septic drain, then I can periodically clear the sediment filter with very little water (still replace the filter element entirely once in a while). Does this seem like it would mitigate the sediment problem? (I guess it depends on the particle size and volume; but I'm hoping that my sediment problem is minimal -- that just seems severe because my tank has been acting as a sediment filter for 4 years, with no cleaning).

I see there are some automatic back-washing filters ... in looking for a large-volume clear spin-down filter housing, I found the automatic iSpring WSP50ARJ Spin-Down Sediment Water Filter with Touch-Screen Auto Flushing valve (50 micron stainless-steel fine mesh element) -- maybe this upstream in my otherwise unmodified system? Or this and add another 5 or 25 micron canister between it and calcite tank? I wish I could find a 20 or 10 micron screen for this auto spin-down flusher.... maybe setup a DIY timer for solenoid valves to flush a smaller/generic spin-down that allows finer micron elements. (Yup, this all just to eliminate the large volume of water for back-washing a media-tank filter.)

I'll see what a 25-micron element in my existing can looks like in 30-days. (Calcite tank is bypassed for now). If it collects a LOT of sediment quickly, then I guess it's time to call the diller and ask them to look at the well itself--maybe they frequently do the geyser-style-cleanout in my region.

If I do go with back-washing, and I'm NOT trying to clear a wide range of contaminants -- just sediment and lift/unpack the media, AND I have the auto-flushing pre-filter -- then do you think I can get away with a short 6-min-flush + 4-min-rinse = 10 min cycle? if in a 10" tank, then that's 6GPM for 10min = 60gal****, say once per week -- that's about my comfort limit on draining into septic. I could periodically inspect the top of the media for the appearance of sediment accumulation, and adjust times as needed. (when I reroute my outside-use water away from the filtration system, my total use of the conditioner will be much reduced). If I find that sediment IS accumulating then I could run some long cycles in the summer out to the lawn, or route it into the sprinkler system.

****the prescribed long cycle uses 150+ gallons, and that seems like a lot to let into a septic tank in one go, every week.

I'm sure my well pump and tank are sized large enough for some pretty substantial flow rates. The side branch where I placed tank and filter is 1", a little smaller than the 1-1/4" trunk, but maybe it can still support the needed flow rate to back flush the 14" tank.

If change to back-washing, I might replace the tank with a 10" to reduce the necessary volume of water used, because I'm reluctant to have to install a pipe and dry well in the yard for this purpose, and so I'd consider draining into the septic system for a lesser amount (unless you all say 'no,no,no!'). I'm happy to spend on a smaller tank since it solves design/performance issues. (We actually may not using enough water to allow upflow system to keep the calcite granules loose in a 14"(13") tank, so I may need a smaller tank either way)

PS, The other reason I went BIG on the calcite tank is because the property has a barn and two gardens. 1-1/4" copper runs to the other side of the basement, then 1-1/2 poly pipe runs through the foundation wall out to the barn, then off to the gardens. All this is fed by conditioned water. I know I shouldn't send conditioned water to the outside, it's just piped this way becasue the existing plumbing near the well equipment made it easy to install the calcite tank and filter off of the two valved stubs (thankfully the sprinkler take-off is upstream, so it doesn't go through the calcite tank). What I NEED to do is to run another 1-1/4 pipe, sourced from before the filters, to the far side of the basement (beyond the bathrooms) to feed the barn and gardens, and repeat for all outside spigots. I've just been dreading this task.

PSS, I have the opportunity to ONLY reroute raw/unfiltered water to the barn and ornamental garden, but keep conditioned water to the vegetable garden. Opinions?

Thanks again

 

[Reach4]

"let-er-rip " was what I was picturing. You could hook up a 1 inch ball valve, and see what kind of flow you can maintain while the pressure at the pressure gauge stays above 25 psi.

It sounds messy to take a flow reading. I would see how fast you can fill a 5 gallon bucket near the end of a 10 minute backwash. GPM=300/(seconds to fill)

You would do that perhaps each week after changing out the media. If your tank is natural color (unpainted) you can shine a bright light thru in the dark, and see the bed expansion. If you can get your bed expansion, you don't have to measure GPM.

Your old calcite is not going to work right. It has probably turned into a big solid with channels thru it.

 

[Chevsky]

I did a "forward flush" as you suggested. that cleared out a LOT of sediment.

The pressure tank is big, so I had a lot of high pressure water to perform the flush. Flow rate starts high, and tapers off as the tank empties and the pressure drops. With the tank bypassed I can get 20GPM. With the tank in-line, for each of three 5 gal buckets in sequence:
1st - 20sec - 15 GPM
2nd - 30sec - 10 GPM
3rd - 35sec - 8.5 GPM

I could hear the media swirling at the top of the tank. The first 2-3 5-gal buckets were very dirty (black!), and then buckets 4-8 were only just cloudy, and then beyond that it cleared up nicely. After 8 buckets I ended up attaching a two more 5/8 hoses and ran it out to the woods, 150ft of hose total, and still maintained 6 GPM after 10 minutes with the pressure tank drained down and the well pump running. Of course, I don't know how well the media was cleaned, and because it's upflow and sediment is coming in at the bottom I assume that this only expelled the sediment that collected at the top and some distance down from the top. When I open the tank I'll know better and probe the media to see if it's hard-clumped.

The drain is a tee off of the 1" copper line, which is a 3/4 NPT hose bib (1/4 turn ball valve). Connected to that was a 50' 3/4 garden hose. So I think I could get adequate flow if I pipe a 1" ball valve into the septic drain which is only a few feet away (install a wye?), and perhaps with frequent short purges I can maintain 10-13 GPM for cleaning.

On the other hand, maybe it's best to switch to a down flow and install a reversing valve. I could run it shorter times than prescribed to conserve water, say each week for a 2-3 minutes reverse backwash, then 1-2 minutes forward rinse. I'm considering a sediment prefilter upstream of the tank -- Ispring Reusable Sediment Spin-Down Water Filter with Scraper and Auto Flushing Module, 35 GPM, 1 in, 50-micron screen, $200 (there's a larger one but it's almost twice the cost) -- which would purge every day for a few seconds. I think the automation would be helpful. (and tho I imagined concocting my own DIY automatic back-flushing 4.5x10 filter(s), a commercial tank-based timed reversing valve would take all the guesswork plus trial-&-error out of it.)

I had wanted to wait to reply until after I opened up the tank to inspect the top of the media, but that might not happen for another week... But so far, after the forward flush, and after a few days, the 25micron 4.5x10 canister filter is still fairly clean (it got stained a bit before I flushed the tank since there was sediment). If I put in the prefilter then I'm going to switch to 5-micron filters in the 4.5x10.

But maybe this periodic forward flush is all I really need, and perhaps a 5-year complete change-out of the media. My brother has the same [supposed] set-it-and-forget-it system, but he's in upstate NH and has a deep well (not sure if it's deep into granite or sand). I'm near Cape Cod and it's sandy. He may have the same problem lurking, so I'll have to break open his tank to see.

 

[Reach4]

Good. I would run your 15 gpm flushes to the yard, rather than the septic field. If it is cold, there could be some ice in the yard for a while.

When a timed valve backwashes at 2 am, the pressure tank could start almost empty of water. With your manual method, you can backwash. Wait for recovery. Flush again with a full pressure tank.

Doesn't your calcite tank have a little fill port that allows access without removing the valve? If not, that might be another reason to get a new system. Is that peristaltic pump injection from a soda ash (sodium carbonate) solution tank looking better?

 

[Chevsky]

Yeah, the soda-ash solution is intriguing. But my water is 5.9 pH, so maybe not quite acidic enough to warrant soda-ash. I also wouldn't use the pressure tank as the contact tank since I send a lot of non-house water to the sprinklers, unconditioned, which would be sourced from upstream of injection point. So for me this would require an extra contact tank.

I like your idea of just doing the forward-flush manually, because I can coax the best flow by waiting for pressure recovery, ... "rinse and repeat". With soda-ash I'd still need an array of sediment filters--I just wouldn't need to guess on the condition of the calcite media (if clogged with sediment and how badly), and expel many gallons of water during wash cycles.

The funny thing is, as I've posted to this thread I've become more and more knowledgeable and my feelings towards different designs and components is changing... When I first posted I was coming off a panic that the sludge was algae. Then I realized that the calcite tank was acting as a sediment filter, and that this simple upflow-never-backwash system wasn't conceived/designed for me because I have some (albeit small) sediment.

Now I'm weighing the cost of modifying -- say, switch to back-washing, or to soda-ash injection,... -- vs just leaving it as-is but manually forward flushing once in a while. I'm realizing that I've been using a 25-micron cartridge filter downstream from a ~5-micron (the calcite tank itself) + screen combo (the tanks exit screen). I've been watching YouTube videos on the vast array of spin-down filters (no magic bullets -- some leave partially clogged screens even after they've been flushed), and contemplating how to mix up manual and automatic processes to balance ongoing maintenance efforts with complexity and cost. Being a mech-engineer I'm tempted to hobble together timers, relays, solenoid or motorized ball valves... or maybe buy a "package" and be done with it (my wife's vote).... or to just accept that I need to forward-flush the system once in a while and be glad I at least know what's going on. (I'll will certainly update this thread...)

Re tank fill port -- Yes, the tank does have a fill port on the side of the dome. I was just saying that I might customize the cap to take a borosilicate glass disk (or cheap USB scope) as a sightglass to see what's going on inside when it's settled (inspect for sediment) and when it's flushing (confirm the media is being lifted), so i don't have to take the cap off to check the degree of sediment accumulation. (tho that might just be apparent if using a 2-micron downstream canister filter with a clear bowl).

 

[Reach4]

Good deal on the revelations. If you switch to a backflushing valve, that will be downflow while in service. That way bursts of water use would not lift dirt into the output pipe.