We installed a 500 gallon cistern about 15 years ago that collects rainwater from our roof and there is sediment collecting in the cistern bottom that I want to pump out periodically. I have a de-watering pump but it can't do the job well because the bottom of the cistern is corrugated preventing the pump from descending low enough to do its job. The gutters are all covered with a perforated screen to prevent leaf entry but pine trees can aim their needles at the holes and over time hit the target and they get into the system and eventually rot. Now we have a couple of inches of sediment due to this.
A trash pump is too much of an investment for such an infrequent pumping schedule so I am looking for ideas for something I can fabricate. I would like a suction pipe I can "sweep" the bottom with but need something to provide the suction. FFers are good DIYers so I am looking for ideas. I can provide pics if it helps.
Sounds like a perfect job for a pool pump and filter. I often see these on the used sale boards for cheap and they have a brush end on a long pole with a pump and filter canister. Filters through and pump the water back in. That might be your ticket. How big is the bung hole in the top of the tank?
I like the pool filter idea.
Add a pool vacuum handle, nozzle/brush and hose and you can scrub the corrugated bottom clean using the pool filter just like vacuuming a pool (less frequently of course).
Dang!! Nice ideas. The bung hole is about 30". I don't need to filter the water - just dump it on the ground anytime the tank is near full. Probably in a winter when we don't water the garden.
I knew I was asking the right people.
Will it pump sediments? I can't imagine someone swimming in a pool with a couple of inches of sediment in the bottom.
is it bio mass, or is there sunlight, and poss. algae? few bits of bleach, if it is for gardening.
Yeah the brush handle arrangement that Ted mentioned will suck right off the bottom and the brush will loosen anything that is stuck.
On my rain water tank I added easy to pull and clean window screen which catches almost all of the little stuff that gets that far, except sand. I just shake it out a couple times a season. Takes 5 seconds.
Use the pool vacuum hose, the handle and brush and set up a siphon. It will pull that stuff off the bottom.
No pump required. I had an algae infection in my pool last year. To get rid of it, I used the siphon method to vacuum it off the bottom. I just ran the water across the yard.
I used a bilge pump to drain the water from 2 digs runs when I ran a water line 6 ft. deep for 500 foot. The power was 3 ft deep. The runs were completely full running downhill for the last 100 ft. Hooked up the bilge to an old garden hose to pump it out. I had to charge the battery while it ran but it did. It run for 3 days with that chocolate water out. :)
When vacuuming a pool with lots of sediment I would bypass the filter and dump the water/sediment out, the pool pump should have a basket in it to catch the larger bits so it may need to be cleaned out a few times if you have lots of debris. After cleaning the basket it is important to clean the mating surfaces of the cover to get a good seal.
That being said pool pumps are high volume/low pressure so with only 500 gallons it would only take 10 to 15 minutes to empty the tank with a small pool pump which may not be enough time to clean the tank. If using the filter and recirculating the water I'm thinking a paper filter would plug up quick, a larger sand filter would last longer but will need to be backwashed, the water is dumped during backwash and the source is from the pool/tank.
I would stick a pressure washer in the tank and stir up the sediment as you are pumping (a semi trash pump with a intake screen will work too) once you get all you can with the pump use a garden hose and a shop vac to finish (USE GFI PLUG PLEASE).
I'm 58 and have about 48 years of experience of seasonal pool maintenance which included draining and cleaning every spring. A few years ago I turned the in ground pool into a underground pool.....don't miss it one bit. :)
I would like a link to a pump that can handle inches deep sediment. Multiple passes over it is ok since pumping will not be frequent.
Siphoning would be great but I would need a loooong hose.
Rent the pump?
Quote from: kelLOGg on August 21, 2023, 02:47:15 PM
I would like a link to a pump that can handle inches deep sediment. Multiple passes over it is ok since pumping will not be frequent.
Siphoning would be great but I would need a loooong hose.
You can look at the methods dairy farmers use to pump out their lagoons that have liquid manure with the bedding sand that also settles out in the lagoon.
They have ways to mix/stir the manure and sand that the pumps will handle. Or they pump out the liquid and scoop/bucket out the solids.
I am considering this so I logged on to the website to ask if it was suitable for silt in the bottom of a cistern and they wanted me to create an account - just to ask a question. I'm losing interest now.
Action Pump 900 GPH Manual Lift Pump - 900 MLP (https://www.globalindustrial.com/p/900-gph-manual-lift-pump?infoParam.campaignId=T9F&gclid=Cj0KCQjwuZGnBhD1ARIsACxbAVgqdAXc_vcaMEom0dp03Sc2IxyPpm4zKToXYhldt2PvHO0NvKqUNIQaAsUaEALw_wcB)
Might just be asking to see if you are for real. You are the one seeking the free information that they might have for you.
If it took 15 years to get that much.....
Another option would be to hire a small vac truck ( think porta potty) to clean it out then put some kind of sediment bucket before the tank inlet to reduce the sediment going into the tank. Probably never have to clean it again, just the bucket.
Such a sediment bucket would have to be inside the tank because all the feed lines from the gutters are below grade.
I have ordered a swimming pool hose and I am going to experiment with attaching it to my de-watering pump. The plan is to hang the pump from the cistern opening and let it dangle in the water a foot or so from the bottom. Using a stick attached to the end of the hose I can then guide the hose over the bottom of the tank while it sucks up the crud. I should be able to access the whole bottom of the tank this way. Silt plugging up the pump will be a problem so I will have to learn how aggressively I can guide the hose. Pics will follow when I receive the hose.
I added the hose to the de-watering pump and glued it with Gorilla glue. Hope it holds - doesn't stick to plastic well.
(https://forestryforum.com/gallery/albums/userpics/13036/IMG_0758.jpg?easyrotate_cache=1693301764)
Here's the stick to guide the hose.
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Now the bad news:
Yesterday I found that the cistern was not pumping water. There was water on the crawl space floor, the pump motor was warm AND the threaded PVC output pipe that goes to the pressure tank had popped out of the pump.
(https://forestryforum.com/gallery/albums/userpics/13036/IMG_0759.jpg?easyrotate_cache=1693301765)
I think the motor or pump is locked causing overheating which led to the threaded fitting dislodging. Not much damage to the threads. Very odd to me. Got a new project now that I don't need.
When will the test run be on the new rigging?
Why not just use a wet / dry shop vac? I used to use mine all the time for unplugging the plumbing in my last house. Worked like a charm sucking hairballs out of pipes. I would think it would rock in this application.
Only issue is you would need to drain the tank or you would be sucking all of the water out. You could always make it a yearly thing where you just drain it in the fall and vacuum it out.
Quote from: beenthere on August 29, 2023, 12:05:52 PM
When will the test run be on the new rigging?
When the cistern pump is replaced or repaired.
Quote from: Crusarius on August 29, 2023, 03:02:28 PM
Why not just use a wet / dry shop vac? I used to use mine all the time for unplugging the plumbing in my last house. Worked like a charm sucking hairballs out of pipes. I would think it would rock in this application.
Only issue is you would need to drain the tank or you would be sucking all of the water out. You could always make it a yearly thing where you just drain it in the fall and vacuum it out.
There is no gravity drain in the cistern. All pumping is of water and silt. You must have a powerful wet/dry unit to pump all water with no air. Mine wouldn't do that.
find and old pool pump and filter. you can recirculate the filter water back in, unless the goal is to drain. may waste a bit with back wash.
the pool stores also sell sweeper heads for not too much. you are doing well on your own.
Even our local hardware store sells a pool vacuum brush for $15.
I think its a 3hp craftsman. It works very well on everything.
I replaced the PVC plumbing that was blown out of the threaded hole and tested the pump to see if it would still pump water. Much to my surprise it worked very well so I reconnected it to the cistern plumbing. The threaded male end had shrunk and lost its grip and got blown out. Never heard of such a thing but all is well now.
Now, back to the opening topic. I put the de-watering pump in the cistern and supported it as shown in the pics. I lowered the suction hose to the bottom, turned it on and crud began to come out. I would get clogged easily so I turned the power off to let the water (and crud) drain back in the cistern to clear the clod and repeated the process. Clogging was so frequent that the process was frustrating then it clogged so badly that I had to pull the de-watering pump up and found that pine needles had clogged the intake. Okay, this idea is not going to work. I have to have a more powerful pump. I am reluctant to hire someone to do this job because there is a lot of hardware in the cistern that I fear they can dislodge or damage: 1) foot valve, 2) aeration pipe to kill anerobic bacteria, 3) low level shut off switch and 4) a vertical steel rod on which I put mosquito dunks to kill mosquitos. It's back to the search for a bigger pump.
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(https://forestryforum.com/gallery/albums/userpics/13036/IMG_0771.jpg?easyrotate_cache=1693580870)
Yeah, pretty tough moving organic sludge through a garden hose. I have a 120 GPM 1-1/2" pump that would likely pull all that and more (sticks are always a problem though.). I bet HF has something you could use or maybe a neighbor has one you can borrow?
I think it is going to be hard to find a way to remove that much sludge with that little water without pumping it all out which is why I suggested stirring it up with a pressure washer (unless the tank and plumping won't handle a pressure washer. In that case use a garden hose) and pump it all out then finish up with a wet/dry shop vac and garden house.
If doing it that way your existing pump would probably do much better (not pumping from the bottom), A inlet strainer would help to.
The pool I refer to cleaning was 25000 gal and we would loose about half of the water trying to pump and clean at the same time. After trying all different kinds of ways we found it easier to pump out the pool then pressure wash it and finishing off with a shop vac.
Its a short 2 month pool season with a outdoor pool here so it sat idle a long time and being a painted cement pool it needed to be touched up every year and re-painted every few years too so pumping it out was the best way.
Hilltop, you helped me put 2 and 2 together better. I said earlier that I didn't mind pumping it dry in the winter when we don't need water for the garden. I didn't think of stirring it up during pumping - I just planned on sucking the muck up off the bottom - which was too much for my de-watering pump. All I have to do is connect a hose to the cistern tap, turn on the water to stir up the bottom deposit and use the de-watering pump to suck up the suspended slurry - a lot more doable than what I tried today. Thanks for repeating your suggestion.