Alk issues

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I hope someone can explain to me why I am having a huge differences on alk between tank water and new batch of water. Alk in the tank is 5.5 dkh and mixed salt water is 11 dkh. I am using RC and have been doing 25% per week. 3" DSB in tank and 6" DSB with chaeto in sump. I only have a few palys and sps frags so i doubt it's my coral that is consuming all the Alk. :headwalls::headwalls::headwalls:

Currently I am not dosing anything and just keeping up with regular wc.

NO3: 2.5ppm (salifert)
PO4: 0.05ppm (Hanna)
Cal: 450 (salifert)
temp: 79
tank: 180G

Appreciate anyone input on this.
 
I am fairly new to all of this but I was having similar issues with low alk (although I have lots of corals). The one element I wasn't testing enough for was Mag. Without that being stable your alk, cal and ph will be all over the place. Since running steady mag at 1350 I have had all other parameters fairly consistent with a little dosing because I only do water changes every 4-6 weeks. Alk at 5.5 is very low normally try and run it between 8-11dkh.
Some one more experienced can probably confirm or dispel what I have just said, so looking forward to the answer.
 
I didn't notice my cal dropping significantly until got more coral and tank started to get a lot of coroline. My alk was dropping and not holding steady at all until mag was sorted. I would double check the mag & alk test kits are in date. Maybe take some water to LFS for testing to double check. I am still thinking a mag issue if you don't have many corals.
 
I recently had this problem as well and it's fixed now. I had a 3" deep sand bed in my 14g biocube and after 2 years, it started causing all sorts of problems where the all was dropping from 10 down to 6.8. The amount if bacteria was just sucking up all my alk so I removed all the sand and replaced it with brand new sand and made it only about a 1/2" deep. I haven't had any problems since and it's been about 3 months so far.
 
What is the salinity/sg in the tank?

If coraline is growing it consumes alk.

High magnesium will not deplete alk; it will slow it down.

Waht are the ammonia and nitrate levels?
 
I do have coralline growing in the tank and salinity is 1.025. What can I do to stablize alk and will I solve the issue just by dosing b ionic.
 
You can dose more or the 2 part solution( alk and calcium) you ae using to meet demand or use a generic recipe of baking soda( baked or unbaked) and calcium chloride per one of the recipes provided by Randy H Farely in the reef chemisitry articles articles listed in the iticky at the top of this forum. The other methods for adding calcium and carbonate in balanced proprtions iclud a calcium reactor and limewatere (kalk) dosing.

Let's look at where the alk might be going:

Biotic precipitation of calcium carbonate( coraline ,corals and other calcifying organisms, at a rate of approximately 2.8 dkk per 20ppm calcium. The bionic and othe commercial mixes are mixed to those proportions of alk and calcium .

Abiotic precipitation ,evident in white crusting on pipes, heaters, pumps etc.

Consumption of alkainity as ammonia is degraded to nitrite and nitrate in the nitrogen cycle can also be part of it The nitrate puts back the alk taken out in this process when it goes to N2 via anaerobic bacterial activity but if the nitrate it's removed via water changes the put back doesn't happen.The sand you have may be holding enough degrading organic matter and /or be clogged to a point where not much N2 processing is occurring and may be a contributing factor .Detritus build up anywhwere in the tank could also be part of it..
 
Some tanks consume 2-3 dKH per day of alkalinity, so I suspect your tank just needs regular dosing now. You might want to check the magnesium level, but it's usually at acceptable levels.
 
So I tested my Mg with Red Sea and it came to 1360. Cal is at 430. Also, I dosed 40ml of Kent tech cb part B (alk) and alk increased from 5.5 to 7.5. However, when I tested alk the next morning, the alk dropped back to 5 ish.

Is it normal to dose daily 40ml or more on a 180G and is there another 2 parts that is more effective.
 
40 ml is a very small dose for a 180G. I dosed 2-3 dKH per day for years into a tank with a lot of coralline algae growth. 2 dKH overnight might be a bit high. I'd look for signs of precipitation, but I wouldn't worry much.
 
So I tested my Mg with Red Sea and it came to 1360. Cal is at 430. Also, I dosed 40ml of Kent tech cb part B (alk) and alk increased from 5.5 to 7.5. However, when I tested alk the next morning, the alk dropped back to 5 ish.

Is it normal to dose daily 40ml or more on a 180G and is there another 2 parts that is more effective.

How soon after you dosed did you test?

Also assuming you followed the Kent Tech directions, how much did you expect it to raise your dKH by using 40ml?

Lastly, how stocked is your tank with SPS and LPS?
 
The direction said 10ml per 40 gallon so I dosed 40ml for my 180G. Alk is now 6.3 and I will dose another 40 ml and recheck alk tomorrow morning.

I only have a few sps frags and lps and I doubt the frags are taking up all the alk.

Is Kent tech cb as effective as dosing B ionic?



How soon after you dosed did you test?

Also assuming you followed the Kent Tech directions, how much did you expect it to raise your dKH by using 40ml?

Lastly, how stocked is your tank with SPS and LPS?
 
The Kent and B-Ionic products might vary a bit in their concentration, but they have basically the same ingredients.

The instructions mostly are for people who aren't testing, so they are very conservative. Since you're testing regularly, you can ignore them.
 
Not for nothing, but I have had bad salt batches from kent..... Alk was all over the place... Switched to Red Sea pro, and was happy... But then I got a bad batch of that, and just switched back to kent.... Make sure your salt mix is testing properly... Could also be the culprit
 
FWIW, water changes can never keep up with alkalinity in a reef tank with growing coralline or hard corals unless you change 10-50% daily. :)
 
The direction said 10ml per 40 gallon so I dosed 40ml for my 180G. Alk is now 6.3 and I will dose another 40 ml and recheck alk tomorrow morning.

I only have a few sps frags and lps and I doubt the frags are taking up all the alk.

In my 90g with a couple lps and sps. I dose 50mg of 2 part everyday.
With a swing like that I would go with a dosing device.
 
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