Sediment pump ideas needed

kelLOGg · August 21, 2023, 08:27:54 AM

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.

Old Greenhorn · August 21, 2023, 08:48:20 AM

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?

SawyerTed · August 21, 2023, 09:27:03 AM

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).

kelLOGg · August 21, 2023, 09:45:28 AM

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.

doc henderson · August 21, 2023, 10:13:24 AM

is it bio mass, or is there sunlight, and poss. algae? few bits of bleach, if it is for gardening.

Old Greenhorn · August 21, 2023, 10:23:25 AM

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.

SawyerTed · August 21, 2023, 11:31:57 AM

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.

Mooseherder · August 21, 2023, 11:34:30 AM

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.

Hilltop366 · August 21, 2023, 12:42:15 PM

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.

kelLOGg · 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.

SawyerTed · August 21, 2023, 03:15:18 PM

Rent the pump?

beenthere · August 21, 2023, 04:38:06 PM

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.

kelLOGg · August 22, 2023, 11:44:26 AM

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

beenthere · August 22, 2023, 11:12:45 PM

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.

Hilltop366 · August 23, 2023, 02:28:43 PM

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.

kelLOGg · August 26, 2023, 07:03:30 AM

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.

kelLOGg · August 29, 2023, 05:59:10 AM

I added the hose to the de-watering pump and glued it with Gorilla glue. Hope it holds - doesn't stick to plastic well.

Here's the stick to guide the hose.

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.

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.

beenthere · August 29, 2023, 12:05:52 PM

When will the test run be on the new rigging?

Crusarius · 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.

kelLOGg · August 29, 2023, 04:25:20 PM

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.

kelLOGg · August 29, 2023, 04:29:00 PM

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.