cant stablize this alk!

[lewismw]

I have been running a 150 gal system for a few years now and recently I miss dosed my ESV BIonic Ca/Alk buffer by adding 4 times more ca than alk.

Ever since I have been suffering a low alk level around .6.2KH/2.17alk, 420ca, 8.3ph. I can bring it up to where i want it (8.0KH/2.86alk), but over the coarse of 12 hours it will be back down to 7.0KH/2.51alk. So I bring it back up again by dosing equal parts, just to do it all over again in the morning. I have done 4 x15% water changes in the last month.

The Ph is exactly follwing this trend also. So much to the point that i dose the tank until my ph monitor reads 8.3 and all is wondereful in the world until the next dose.......
So my question is why wont it stick! I have never had this problem before. :confused:

[MCsaxmaster]

That isn't necessarily surprising in a tank with a good amount of calcification. I used to have a heavily stocked tank that would drop from ~12 dKH to 7 dKH over the course of about 12-14 hrs. Dropping 1 dKH in this time span isn't unusual or even a lot necessarily.

[ishmael]

This is a great discussion of this problem.

http://www.advancedaquarist.com/issues/nov2002/chem.htm

[jdieck]

ESV increases PH substantially at the point of addition and may be causing precipitation thus dropping the level. If you see precipitation in the form of slight snow effect or if you see white crust or white film on heaters powerheads or surfaces then precipitation might be the issue.
FOr two or three days try adding half of the amounts you are adding and do it very slowly not to increase alkalinity over 8 dKh for a couple of weeks and see how it goes. If everything stabilizes then you can increase the dose slighttly to take alkalinity to 10 dKh.
Also insure that your alkalinity kit is testing properly and that your magnesium level is around 1250 to 1300 ppm.
Also check that the salt you are using does not have either very low or very high alkalinity.

[lewismw]

<a href=showthread.php?s=&postid=11917113#post11917113 target=_blank>Originally posted</a> by jdieck
ESV increases PH substantially at the point of addition and may be causing precipitation thus dropping the level. If you see precipitation in the form of slight snow effect or if you see white crust or white film on heaters powerheads or surfaces then precipitation might be the issue.

Also insure that your alkalinity kit is testing properly and that your magnesium level is around 1250 to 1300 ppm.


You are right on! thanks for the help!!!!, After some research i believe i have reached the point of abiotic precipitation of calcium carbonate. I have been noticing for the first time ever the white crust forming on heaters and surrounding areas.

I am out of my Mg test, but i have dosed a small amount till i can get to the LFS tommorrow.

[mixed_reefer]

<a href=showthread.php?s=&postid=11916347#post11916347 target=_blank>Originally posted</a> by MCsaxmaster
That isn't necessarily surprising in a tank with a good amount of calcification. I used to have a heavily stocked tank that would drop from ~12 dKH to 7 dKH over the course of about 12-14 hrs. Dropping 1 dKH in this time span isn't unusual or even a lot necessarily.

I really need a calcium reactor if this is the case. I dump in so much alk now and most of my stuff is just small stuff, the tank is under a year still.

[jdieck]

<a href=showthread.php?s=&postid=11918745#post11918745 target=_blank>Originally posted</a> by mixed_reefer
I really need a calcium reactor if this is the case. I dump in so much alk now and most of my stuff is just small stuff, the tank is under a year still.
Check if you have or notice precipitation, if so it can give you the impression that you have a high consumption when in reality part of your addition goes into making sand :D

[mixed_reefer]

Im adding about 1 dkh per day maybe a hair more recently. Does that sound about right for a 30g chocked full of sps? I have about 65 gallons worth of sump and fuge on the system after displacement. There are no corals in either of those, the sump is pretty much full of live rock and the fuge is chaeto and mangrove seed pods as a recent addition. I keep an close eye on mag and i run it in the 1400's to try and combat any precip. my pH as of last night was 7.94 with a recently calibrated probe.
I forgot to mention i drip kalk 24/7 at about a drip every 2-3 seconds, the system is 3 open top tanks with metal halide on 2 of the tanks and i get plenty of evap to still add my additions and need to top up some fresh. I dont drip kalk like crazy to keep the ph within reason to combat any precip.

[jdieck]

1 dKh per day is not unusual and even a bit on the low side for a tank loaded with sps.
Try keeping your alkalinity at around 10 dKh and try improving the ventialtion with outside air around the tank so your PH improves. If you are dosing with baking soda try baking it so in turn it will increase PH rather than pulling it down.

[demonsp]

Well readings like PH and Alk will change during daily reef tank living. The reading you get in the morning would be the reading i would go with. Trying to balance levels from daily activity would only hurt.

[mixed_reefer]

Lot of it is small Jose, frags and small colonies, tank is under a year. I dose bake soda baked and live in an old drafty house. I take my pH reading before i add any buffers and i always do it at night so that ph is my low point. I could always up the kalk drip if it becomes an issue. Thanks for the insight! I have not noticed any calcium buildup on the pumps or heaters in about 6 months im proud to say. The tank was a bit hairy at first but it has settled down alot. My alk demand just keeps getting more and more at an alarming rate. I seriously need to consider a reactor so i can leave my house for a few days without my alk plummeting.

[mixed_reefer]

I also run at 10 dkh per your earlier advice. I really want to thank you Jose, you have been a life saver and an inspiration for me. Your endless advice is greatly appreciated. Thank you

[jdieck]

Glad your tank is doing fine and do not worry much about that consumption. My alkalinity consumption is 3 dKh per day right now. I estimate my tank grows by 50 pounds every year if I were not to prune the corals

[lewismw]

so if my Mg is 1250 what is the best way to combat precipitation?

[mixed_reefer]

Precip happens at high pH, say above 8.4 is getting too high. Magnesium also helps keep the alk and cal suspended in solution, when mag is low it is much easier to have a snow storm of precipitation.

[lewismw]

my ph swings precisely with alk swing as i dose---->....from lowest kh/alk 6.4/2.29, ph7.9 to highest(and where i want it) kh/alk 9.0/3.2 ph8.3.

I am out of my salifert Mg test...I hope the LFS has a good brand................................ in route to get a Mg now.

[jdieck]

<a href=showthread.php?s=&postid=11919739#post11919739 target=_blank>Originally posted</a> by lewismw
so if my Mg is 1250 what is the best way to combat precipitation?
That magnesium level is not bad. Try keeping it within 1250 and 1350 ppm.
As I emntioned above the best way to prevent precipitation is avoid a sudden increase in PH during the addition of the alkalinity part of the supplement, adding it very slowly in a high and turbulent flow area and for a couple of weeks use less supplement and target to maintain an alkalinity of only 8 dKh.

[lewismw]

thanks jdieck.
I am taking your advice on cutting back.... but it seems as if i am dumping equal parts of bionic just to keep it in the mid 7'sdkh with a ph of ~8.04.

I have read where organics play a part in the war against non-biologic precipitation. I recently added a carbon reactor, so i have shut this off until i get this resolved.

The water changes i have done have been followed with a good amount of bionic to get the levels back up. Do you think perhaps a big water change with no additions is needed? or would help?

[jdieck]

Have you tested your newly mixed water? What is it's alkalinity and calcium levels? What salt are you using?

I would recommend adjust the levels of the new mix before making the water change.

[lewismw]

i use instant ocean and will test my new batch of water shortly. I posted not too long ago and have been thinking of switching to TMP. this may be a good time to try that out! :-)