Cistern Question - Dissolved Solids - How to Deal With It Now?

Rick · #1 05/09/14, 09:12 AM

Would you bleach and scrub a 8 month old cistern?

My wife Ann wants to climb in, spray and scrub the walls. I am not sure it is warranted.

In late September 2013 we had a 1300 gallon cistern installed, which we immediately filled 2/3 full with well water. We have yet to plumb in OR out of it. We didn't observe the water from the well that we filled the cistern with, but we have never had any mud from the well before - just some orange minerals that always settle out.

The risers (vertical columns for manhole covers) were in place - but not sealed for months, other than some quickly duct taped plastic bags around the circumference. The mounds of dirt sat adjacent to the area during heavy rains.

Finally, in December, we sealed the risers where they sit in the manhole openings on the cistern with a product called "Through the Roof" and covered the top of the cistern with the dirt to insulate.

Around February 1st 2014 when our water line froze in the severe (to us) cold, I baled some of the water FROM THE TOP OF THE WATER - without disturbing the water at the bottom - to use. The water was murky, marble like - with dissolved dirt solids in the bucket. The solids never settled, even 5 days later.

Today I dipped a couple of gallons out to make sure the cold weather wasn't what was keeping the solids suspended. The water still looks lie very, very diluted - liquid mud .

Would you spray with a bleach solution, scrub and rinse?

Do you have any ideas on the dirt suspended in the water?

Harry Chickpea · #2 05/09/14, 12:20 PM

Probably a lot of dissolved calcium. Leave the water in place. Bleach will act as a flocculant and remove a lot of it. Alum would do the same only better. Put a submersible sump pump ($60+- Harbor Freight) in and run the water through a whole house filter case ($40+- Lowes) and 5 micron yarn filters (2 for $10+- Lowes) and back to the cistern. You can get it sparkling clean in about a day or so.

While you are at it, pick up a small pool test kit. If the water is excessively alkaline you may need to add a little acid to balance it out.

I do not recommend EVER going into a cistern. Use a hose or wand from outside.

maddy · #3 05/10/14, 07:06 PM

I'm pondering a similar question--how to clean a holding tank that is quite a ways up a hill. I could conceivably connect a 5 or 6 hoses and drag them up the hill to a pressure washer, but I've barely got enough water pressure to run a pressure washer at ground level, much less 500 feet up the hill. Any ideas how to clean a tank from outside it when the water source is far away?

backwoods · #4 05/10/14, 09:48 PM

Could someone with a tractor perhaps, haul a portable water tank up there for you? I'm talking about the type of tanks you haul in the bed of a pick up. You could attach a water hose with pressure valve handle and it wouldn't be as good as a pressure washer, but should get the job done.

Harry Chickpea · #5 05/10/14, 10:52 PM

Sump pump, hose, small generator.

Garden sprayer & bleach

Gas powered transfer pump

Those are just a few off the top of my head.

ceresone · #6 05/11/14, 09:43 AM

Whatever you do--DO NOT go into that Cistern with bleach! You wont climb out!

Rick · #7 05/11/14, 01:55 PM

Thanks for the words of caution to Ann, especially with my reading this on Mother's day.

And you are right, I may as well keep her another 40 years

I will try the alum soon - I had heard this from one of my customers also.

I suppose if we added bleach, we would let it settle for a week?

Any idea how much to use for 800 gallons?

Doing the pumping and filtering - would we recirculate from end of the cistern to the other?

We will have to use either a 2000 watt or 3500 watt generator for this.

Do you have a recommendation for a substance to add to bring up the acid level if needed?

Harry Chickpea · #8 05/11/14, 03:34 PM

When using alum or bleach, mixing is important. Alum could drop in as a lump, settle to the bottom and not do much. Bleach will diffuse over time, but an initial "stirring of the pot" can speed things up. (small amounts of alum are commonly available in the spice or preserving sections of a grocery.)

800 gallons isn't much. I would GUESS around a cup or 12 oz of bleach would be plenty. With recirculating, it is a little weird. In an in-ground pool, there are a couple of suction points - the skimmer on the surface, and the drain at the bottom. The outflow is all around the pool and dirty and clean get horribly mixed, but it somehow all gets cleaned in a short time. I've always been a little surprised just how effective it is.

There are a couple ways of attacking dissolved solids - the constant agitation and use of a filter will load up the filter, which can then get cleaned. The other way is agitate, let settle, and then clean off the bottom. If the cistern is on a hill, you might be able to use a hose, wand and attachment like the brush for a vacuum cleaner to sock up the sediment and discharge it downhill, using the hose as a siphon.

Acid levels are commonly brought up with tiny amounts of muriatic (hydrochloric - HCl) acid. It is the closest to the natural ions of water. You can use others if you want. Vinegar or acetic acid is C2H4O2, it is fine but it adds a little carbon and is a little less effective. If the water is out of balance pH wise, much of the acid will get bound up in making the precipitate and sediment anyway. If you plan on using alum, add the alum first and wait a couple hours before testing the pH again. Alum is also a significant acid.

Cyngbaeld · #9 05/11/14, 04:22 PM

Why don't you just pump the water out and refill?

Rick · #10 05/11/14, 06:36 PM

Quote:

Originally Posted by Cyngbaeld

Why don't you just pump the water out and refill?

Excellent thought, and not out of the question - it so far is our intent - but Ann was worried about the tank walls and considering climbing in and scrubbing the walls with bleach spray???

I would like to solve the puzzle and learn how to cope with it.