Limewater not keeping up with Ca and Alk

[lakee911]

I use saturated limewater for my top of water to my 120G. It seems that I'm always low on Ca, Alk and Mg. I don't change water often, so I know that I'll need to supplement Mg and I do, but that's about it.

At what point do people start adding Calcium Reactors and does that help with Alkalinity? I do run Phosban, so that might be consuming some Alk.

Here are my parameters (without water changes) from Oct 14, 2007 and today (Jan 5, 2008)

Salinity: 1.0233, 1.0225
PO4: undetectable, undetectable (salifert 2x resolution)
NO3: 5ppm, undetectable
Alk: 8dKH, 6dkH
Ca: 440ppm, 350ppm
Mg: 1035, 1200 (I do dose this)
pH: 8.1, 8.0
Temp: 79, 79

I'm currently adding (or will be adding) supplements to boost my Mg, Ca and Alk to 1300ppm, 425ppm and 7.5dkH.

I've got a 120Gal with a lot of coraline and just a few softies. I'd like to slowly add more though.

Thanks,
Jason

[Randy Holmes-Farley]

If limewater cannot keep up, folks can use a two part with the limewater, or a reactor. Some folks add vinegar to the limewater (and more solid lime) to get a little more dissolved, but it sometimes is still not enough for an SPS heavy tank, or one with low evaporation.

How much evaporation do you have each day?

How are you dosing limewater?

[lakee911]

Randy, since I have any auto top off, I'm not exactly sure about the evaporation. I know that I empty my 32Gal brute in roughly a month (give or take a week), so I guess that would be about 1G/day.

I have a DI canister filled about 4" deep with pickling lime. I've also added a center pipe with holes drilled at the bottom. The water flows through the unit backwards, it goes down the middle pipe through the holes (stirring up the kalk) and out the top and to the tank.

The kalk top off water gets dripped into my filtersock as it enters the sump. I have a tunze ato unit so I try to keep it away from that (per tunze recommendation).

Jason

[Randy Holmes-Farley]

If you increased evaporation, you could dose more.

Do you know that top off is saturated?

[lakee911]

I assumed that it would be, but how can I be sure?

[reptilemanmark]

Originally posted by Randy Holmes-Farley
If you increased evaporation, you could dose more.

Do you know that top off is saturated?

How do you increase evaporation? I noticed mine has changed a little in the last couple weeks.

[sjm817]

Since you have a 32G topoff that lasts a month, I would just mix the lime into the topoff and use it. Use 2 teaspoons/gallon, mix it up let it settle, cover it and see how it does. This way, you know you are using saturated limewater.

[Randy Holmes-Farley]

Fans are a good way to increase evaporation, as is opening the hood top.

[lakee911]

I have a fan that comes on automatically when the temperature gets too high. I've turned it on and we'll see if that helps some with evaporation. I can't open the hood entirely all the time (lighting is too bright).

As for mixing the lime water in the brute, if I did that, then my pump is subject to that and it probably wouldn't last very long. I also use that water from time to time for other things so I'd like to keep it clean.

I'll see how the evaportation helps once I get the levels up to where they should be.

Thanks,
Jason

[Randy Holmes-Farley]

Your limewater may be much less than saturated with that setup.

Good luck.

[sjm817]

I use an Aqualifter for limewater topoff. It doesn't seem to hurt them. Its a $12 pump and I've been using it 2 years.

[lakee911]

Sjm817, I have to lift the water about 8-9 feet so an aqualifter wouldn't cut it.

So, how can I tell if it's saturated, Randy? I love this method--I add new lime every few months and I don't have to touch it. I hope that it is saturated and if not that I can make it work.

[Randy Holmes-Farley]

Conductivity is the best way. About 10 mS/cm is close to saturation. pH is a crude way. Alkalinity or calcium measurement can also work.

[sjm817]

Originally posted by lakee911
Sjm817, I have to lift the water about 8-9 feet so an aqualifter wouldn't cut it.

So, how can I tell if it's saturated, Randy? I love this method--I add new lime every few months and I don't have to touch it. I hope that it is saturated and if not that I can make it work.

I have to go ~ 5'. I use two of them in series. No idea if 4 in series would do it. They are only $12 a pop.

[MO Will]

I am interested in determining how saturated my limewater reservoir is

How would I use a calcium or alkalinity test kit to determine that?

Thanks

[Randy Holmes-Farley]

Saturated limewater is about 800 ppm in calcium and about 41 meq/L in alkalinity.

What Your Grandmother Never Told You About Lime
http://reefkeeping.com/issues/2005-01/rhf/index.htm

from it:

Limewater that is saturated with calcium hydroxide has a pH of 12.54 at 25ºC. It is actually recognized as a secondary pH standard. The pH is substantially higher at lower temperature (12.627 at 20ºC and 13.00 at 10ºC), and lower at higher temperature (12.289 at 30ºC; 11.984 at 40ºC). Saturated limewater has a conductivity of about 10.3 mS/cm at 25ºC, and contains about 808 ppm of calcium and 40.8 meq/l of alkalinity. Slightly more calcium and alkalinity dissolve at lower temperatures, and less at higher temperatures.

[ctripi]

lakee911.... look up omega peristaltic pumps http://www.omega.com/ppt/pptsc.asp?r...100&Nav=grel07
28' suction head. They're a bit loud though. Don't recommend mounting in living spaces.

[Icefire]

First I would add some salt to get to 1.026 as you are low for a reef tank.

A tank with 400 calcium @ 1.026 will have 338ppm Calcium @ 1.022

try to up the MG a bit too and retest once at 1.026

[lakee911]

I'm not sure where you all got the idea that I can't pump my water high enough. lol I'm going to see how saturated my limewater is before I contemplate mixing limewater seperate and pumping it.

My alkalinity test is a titration such that 1 drop = 1dkH, so that wouldn't be very practical or accurate.

I use a salifert calcium test, so if I recall correctly, 1.0 mL of titrant = 500mg Ca++, so I'm wondering if I can increase the amount of titrant and have it still be accurate.

Jason

[Randy Holmes-Farley]

My alkalinity test is a titration such that 1 drop = 1dkH, so that wouldn't be very practical or accurate.

You can take the limewtaer and dilute it with RO/DI water before the test to bring it down to a testable range. Say, 9 parts RO/DO to 1 part limewtaer. That should take about 11 drops.

[lakee911]

Ok. That's probably a better way to go. I'll give it a go tonight or perhaps tomorrow. Thanks, Randy!

Jason

[Randy Holmes-Farley]

Let us know what you find.

[lakee911]

41 meg/L = 115dKH

Well, my kalk water is mixing up at a whole 13dKH! That's undiluted with RO/DI.

That means I'm probably getting 90ppm Ca out of it. Considering that I have 120G of water, I'm sure the 1Gal/day is adding <1ppm of Calcium. I better retool this passive Nielson reactor.

Thanks, Randy.

[Randy Holmes-Farley]

Retooling sounds like a good plan.