will lime clean up nasty fresh water?

[bgdiving]

Last wk my RO water was coming out at a TDS reading of 420 ppm and it has gotten worse since then you can now visibly tell the water is deteriating, a glass of water is noticably cloudy and a bucket has a dingy redish brown color. My well water has a TDS of 1700ppm and I assume a good share of that is calcium carbanate,iron and phoshate allong with possibly some tanin. Anyway my well water is very hard on RO membranes and the RO company doesn't want me to replace another $400 membrane untill I install a sand filter infront of my prefilter. The guy with the sand filters was suppose to be out today to check out my system but will be delayed till first of next wk and then it will probably be a wk to 10 days before it's installed and running.

Will adding lime to my top off water and letting it set 24 hours percipitate most of the harmful substances? The sediment at the bottom is a chalky orangish/brown and the water above is fairly clear. I've been using the clearish liquid at the top for top off water and discarding the residue at the bottom. Will this remove most of the phoshates? and if so can I mix salt in this lime water or just use it as top off?

Yesterday I hooked up a small RO unit( about 8 gallons/day) which is meeting about half of my minimal RO needs. Will adding lime to my failing large RO system water get me by for the next wk or 10 days untill my whole house RO is replaced? Already over this past wk have an algae blow up in the tank that has had the greast water change.

Thanks for any and all your help.

[Steve Richardson]

I think your safest bet is to try and find a temporary alternate source of water...

Perhaps a LFS. A local lab or university often has large RO units and might be persuaded into giving you 50G or so to get you by. Could even try distilled water from the store... (not just 'spring' water...some of these can have phosphates in them etc).

Even one of those little 'tap water purifier' by aquarium pharm. deionization cartridges could bridge the gap. They sell them in nearly all local pet shops.

I wouldnt rely on kalk to precipitate water into 'purity'.

hth,

[Randy Holmes-Farley]

I agree.

I have an article posting in May at advanced aquarist that shows that water containing 1 ppm copper can be dropped to 25 ppb using lime . So it can purify the water, at least to some extent with some metals, and may be the way to go if a low metals tank is a goal. Adding a big excess of lime helps this process along.

That said, if the water is so impure that it is colored, the impurities may be very high and/or be things that lime won't impact. So I'd suggest getting another water source too.

Still, if you do use that water, using it via limewater will be better than using it raw.

[bgdiving]

Thanks for the replies. How much is "Adding a big excess of lime helps this process along "? I have been adding about 2 teaspoons /gallon as I fill the buckets, then let it sit 24 hrs without stirring then use the clearish white liquid and discard the percipitate. I'm getting about a 1/4 inch+ of semi solids or powder on the bottem, a good share of it appears to be undisolved lime but it has pulled all or most of the color down with it. I'm discarding the last 2 inches of water and the residue. Is this enough Lime? Should I be stirring it once or twice during the first 12 hrs or so? or just let it set and percipitate out?

I did hook up a small RO unit 2 days ago but it only meets half my minimal RO needs and I'm also concerned it'll go bad a few days as my water deteriates. Right now my main (failing) RO unit is acting like a prefilter for the small unit. My failing RO unit is still cutting my TDS's down by more than half before the water enters the small RO. My product water out of the small RO has a TDS of 40 ppm.

Randy was that copper reduction from parts per MILLION down to parts per BILLION? That's a very impressive drop, does it do the same for phosphate?

[Randy Holmes-Farley]

I did not test phosphate, but I expect it would yes.

The drop was from 1 part per million to 25 parts per billion. A drop of about 97.5% in copper.

To get that drop, I added about 2.5 g lime/700 mL water, and then later added another 2 g/500 mL or so. The second addition was necessary to get that big drop (the first addition gives a drop, but not that big). I think the copper absorbs to the solid lime surface.

[bgdiving]

Randy, when you made your second addition of lime was that after you had discarded the reidue from the first addition? am I correct in assuming you had discarded the residue with 200ml of water? how long did you wait (or how long is it necessary to wait) between the first and 2nd additon of lime? Would you have achieved the same results by adding 5 grams initially or was it nececary to do it in a 2 step process? did you stir your mixture after the initial mixing?

[Randy Holmes-Farley]

I did not discard anything. I added the first amount, stirred 1 h, and allowed it to settle 1 day, then 5 more days. Then I added the second shot of lime, stirred 1 h, and let it settle 24 h. I'm not suggesting this is a necessary routine, but is was the protocol for the experiment. I did not investigate shorter times and such. I'm not sure, but two steps probably aren't necessary, rather the amount is necessary.

[Steve Richardson]

keep in mind, other impurities may not be affected by simply supersaturating with kalk.

fwiw...

shrug.

[WaterKeeper]

Heating the water to near boiling will increase the effectiveness and speed of the lime softening process. The addition of soda ash, sodium carbonate, will enhance the process by removing calcium and magnesium salts in the non-carbonate form. You probably don't need to do that as they are beneficial to the tank.

As a quick and dirty way of knowing if you have enough lime, the pH should be at around 11 at the end of 30 minutes.