Kalk Precip

[Beverly]

Have been dripping Kent kalk mixed with RO/DI water off and on for several months with great success in my three tanks.

After my last water change on the three tanks, this past weekend, the kalk drips into the water and then it precipitates. It looks like it's snowing. In all three tanks :confused:

Haven't done complete alk, calcium, magnesium tests on any of the tanks. I'm sure they are all at least slightly different in chemistry, so I'm thinking my kalk powder is getting old.

What do you think?

[Murminator]

Are the bottles and lines clean? if not it could be a build up of scale coming out, maybe if you can run hot water or vinegar through it.

[Beverly]

Noticed that the kalk drip would stop and that there was kalk build up in containers and lines. Cleaned all three containers and lines two weeks ago with vinegar, then ran some RO/DI through them to get rid of the vinegar. Everything worked fine. Cleaned them again when the precip started using the above method and still precipitating.

[Aquattro]

you need to take Ca and alk measurements...

[medican]

WOW......I was just reading about this........

I think it has to do with the fact that there is not enough CO2 in the water for the kalk to completly react with....... I will go and see if I can find what I was reading........

[Jaws]

you need to take Ca and alk measurements...

Sounds like it could be past saturation point.

[Beverly]

Richard,

Would like to read what you've read. Might be helpful.

Jason and Brad,

Will test tomorrow when the sun comes up. Don't trust my eyes reading tests in overhead light.

Thanks for the tips.

One point of interest: I've been dripping kalk during both during lights on in the evening and early morning, and night. Never had a problem of precip during those day times. At night, I never thought to look for precip, well, because I'm sleeping then. However, there had been no signs of precip the next day while dripping at night. Only noticed precip a few evenings ago. Tried to drip early the next morning and still had precip.

[medican]

this is not it.......way to many articles........ :eek:

but try these

http://www.advancedaquarist.com/issues/june2002/chem.htm

http://reefkeeping.com/issues/2003-05/rhf/feature/index.htm

hope this helps

Yup I think PH is where to start

Good luck

[Beverly]

Couldn't wait to test until tomorrow. Here's what I found:

37g:
- SG - 1.026
- pH (10 mins after lights out) - 8.19
- alk - 5 dKH (very low!!)
- Ca - 320 ppm (very low!!)

67g:
- SG -1.024
- pH (10 mins after lights out) - 8.34
- alk - 6 dKH (very low)
- Ca 380 ppm (low)

120g:
- SG - 1.025
- pH (10 mins after lights out) - 8.36
- alk - 8 dKH (a bit low)
- Ca - 380 (low)

Okay. Alk and Ca are low in all tanks, some lower than others. So why would my kalk precip in these alk and Ca starved environments?

Before the precip problem and after the precip, I have used the following to see what difference vinegar made to my tanks:
- 1 teaspoon kalk to 4 L RO/DI
- 1 teaspoon kalk to 4 L RO/DI plus 1 teaspoon vinegar
- kept kalk mixture tightly sealed and let it sit 24-48 hrs

No difference in precipitation using vinegar or not.

Maybe I should buy some new kalk powder and see what it does...

[Aquattro]

Bev, you're right. Those values do not set the environment for precipitation. My kalk is over a year old, sits open half the time, never does that at all.

[Jaws]

Can you check the oxygen levels in the tank? How about the Oxidation Reduction Potential (ORP)?

[Aquattro]

Can you check the oxygen levels in the tank? How about the Oxidation Reduction Potential (ORP)?

nothing to do with precip, and difficult to test.

[IslandReefer]

Sounds to me like your Alk is not high enough to buffer the pH enough to prevent the ppt of calcium carbonate. You may be getting severe pH swings during the day/night cycle also.
Try the Randy Holmes-Farley articles on Alk,Calcium and pH in the Advanced Aquarist archives for strategies and explanations.
IMHO raising your Alk. with eg. baking soda would be where I would start.
Good Luck

[Beverly]

Guys,

I know all about raising alk from reading Randy's and others' articles. Just don't know why I'm getting precip all of the sudden :confused: I'll post this to RC and see what they have to say.

[StirCrazy]

Just out of curiosity why do you call the two tanks with ca levels of 380 low? that is the ideal value to have.

Also are you getting an accumulation of kalk powder in the bottom of your kalk jug (what ever jug you mix your lime water in and then use to add it to the tank) If you are it could be some of this being carried over.

Steve

[Beverly]

Steve,

Yes, there is a little bit of powder on the bottom of the mixing jug, but not much. When I used 2 teaspoons of kalk per 4L, there was much more powder on the bottom, so I switched to using only 1 teaspoon of kalk powder. Either way, I would discard about the last 1/2 L of the mixture so none of the powder would get into the tanks.

One thing that I find strange is that when I pour the kalk mix into a clear 2L bottle before pouring into the dripper, the kalk mix is not clear as I would sort of expect it to be. However, I used the slightly cloudy kalk mix in the dripper and didn't have precip until my last water change.

[Aquattro]

FWIW, I mix my kalk for about 30 seconds and hook it up to the drip. No problems..

[danny zubot]

I'm having wierd readings in my tank too that have me confused so this topic is very interesting to me. When I test my calcium I get precipitation in the test tube, but not Alk and Ph. the test is only a couple months old.

[Beverly]

The Aqua Dose Delivery System 1400 ml from J&L are the ones I use:

http://www.jlaquatics.com/images/cleaning/aquadose.jpg

Added Kent Liquid Ca to all tanks this morning, as well as a bit of Aquarium Revolution pH and Alk Booster to the 37g, then began the kalk drips to see what would happen (kalk that is being used has been in the drip containers since a couple of days ago):

- 37g is precipitating a bit, but not nearly as much as the last time I dripped, and is still dripping
- 67g is not precipitating at all, and is still dripping
- 120g precipitated as badly as before, so I shut it down

Have to get another test kit to measure Ca in all tanks as I'm running out of titration solution :confused:

Brad,

What kind of drip system are you using? Aren't you concerned that the kalk doesn't have a chance to mix well with your RO water before it goes into your drip container then into your tank?

Danny,

What Ca test kit are you using? I use what is locally available which is the Hagen kit. I shake each solution bottle a bit before using, and I especially mix the second solution for the full 5 seconds that the kit recommends.

[Aquattro]

Brad,

What kind of drip system are you using? Aren't you concerned that the kalk doesn't have a chance to mix well with your RO water before it goes into your drip container then into your tank?



Bev, I make RO water in 5g jugs and stack them. When I change a jug, I mix 80 ml of vinegar and 8 tsp of kalk in a container for about 15 seconds, dump this into one of my 5g jugs, give it a shake and hook it to the float valve. pH of this is about 12, so I know it's close to saturation. So no, I haven't got any concerns about mixing.

[StirCrazy]

FWIW, I mix my kalk for about 30 seconds and hook it up to the drip. No problems..

ya I was getting at a build up over time as I never used to rinse my old 5 gal bucket and after a while if there was a lot of flow it would put solids in, but doesn't sound like that is the problem.

Steve

[Beverly]

Bev, I make RO water in 5g jugs and stack them. When I change a jug, I mix 80 ml of vinegar and 8 tsp of kalk in a container for about 15 seconds, dump this into one of my 5g jugs, give it a shake and hook it to the float valve. pH of this is about 12, so I know it's close to saturation. So no, I haven't got any concerns about mixing.

Brad,

Your delivery system is much different and more forgiving than mine. In your system, the kalk powder has a chance to settle at the bottom of your jug over time. In my puny 1400 ml system, I've got to settle the powder first in my make up 4L jug before adding any kalk mix through my drip.

[Aquattro]

Bev, keep in mind I went thru a 5g jug daily. Not much time to settle really. Watching the float valve, I can see milky kalk solution going into the sump. Just never worried about it, other than mechanical clogging of lines.

[untamed]

It is possible the "low" readings you were getting were due to the fact that you had just gone through a precipitation event. That would have removed a lot of Ca/Alk from the system (I think).

[Beverly]

untamed,

The precip event was short. As soon as I realized the kalk was precipitation, I discontinued the drip. Drip lasted less than 2-3 minutes in each tank, though the little white precip flakes drifted around the tank for another 10 minutes or so.

[untamed]

Once you trigger the precipitation, it will pull Ca/Alk out of the system. It is a threshold. Once you cross, you can loose a lot of Ca/Alk quickly.

BTW...check your pumps. If you were running this close to precipitation, it likely first occuring inside any PH in the system. The heat causes the reaction to occur more easily. If one could see inside one's pumps, they would give warning to when you are close to pushing the Kalk too far...

If the pump impellers are coated, soak them in vinegar to break up the Ca.

[Beverly]

untamed,

Did maintenance on the three tanks yesterday. Always tear apart the 802s and 402s to clean them in a pail of outgoing changewater. Noticed no precip anywhere in or on any of the powerheads in all three systems.

Have not been dripping kalk for a few days. Am going to do a full work up of params this morning. Afterward, may also drip some kalk to see what happends. Will post results.

[Beverly]

Took almost two hours to test the following on my three tanks this afternoon:

37g: (30% water change yesterday)

- temp - 78 F
- SG - 1.026
- nitrate - 0 ppm
- dKH - 8
- pH - 8.10
- magnesium - 1185 ppm
- calcium - 360 ppm

67g: (35% water change yesterday)

- temp - 79 F
- SG - 1.025
- nitrate - 0 ppm
- dKH - 8.5
- pH - 8.25
- magnesium - 1180 ppm
- calcium - 380 ppm

120g: (15% water change yesterday)

- temp - 79 F
- SG - 1.026
- nitrate - 0 ppm
- dKH - 8.5
- pH - 8.25
- magnesium - 1245 ppm
- calcium - 380 ppm

Overall, params look good except for low magnesium across the board. Would also like to increase pH in the 37g. Have not tried dripping kalk yet to see if it precipitates like it did last week after the water change. Will keep you posted.

Will use the Reef Chemistry Calculator to figure out how to adjust the magnesium:

http://home.comcast.net/~jdieck1/chem_calc3.html

[Beverly]

What I did this week:

- used the calculator to adjust Mg in all tanks to 1350
- took three days to add all the Kent Mg to each tank
- have been dripping kalk for the last two evenings and nights in all tanks
- have been dripping 1/2 kalk and half RO during the day in the 120g for top up.

Test results from this afternoon:

37g: (water change will be on Sunday)

- dKH - 6
- pH - 8.11
- magnesium - 1440 ppm
- calcium - 360 ppm

67g: (water change will be on Sunday)

- dKH - 7
- pH - 8.25
- magnesium - 1335 ppm
- calcium - 400 ppm

120g: (water change will be on Sunday)

- dKH - 8
- pH - 8.32
- magnesium - 1335 ppm
- calcium - 400 ppm

Comments:

- unexpected rise in Mg in 37g
- Mg about where I thought it would be in 67g and 120g
- alk decreased in all cases to varying degrees
- Ca either increased or stayed the same