Struggling with low alk

[Iballhog]

On my 34g tank I've always struggled with low alk over the last 1 year. I just can't seem to get my alk over 7dkh. The last 4 months I have really tried to bring the alk up, testing daily and slowly tweaking what I was dosing.
Currently my tests and dosing is as follows:
Cal is 450 ppm dosing 8ml/day
Alk is usually under 7 dKH, Im dosing 24ml/day
Mag is 1300 ppm dosing 2ml/day.

I change about 8% water per week, using aqua forest salt. About 2 months ago I switched from Salinity salt.

It just feels like I'm dosing way too much alk. Especially being so far out of balance.

Picture of the ALK guilty alk consumer

 

[drawman]

Hey those are some big euphyllias definitely great culprits! When you increase your alk do you see less of a downward daily swing? Also, how big is your tank?

 

[Iballhog]

Hey those are some big euphyllias definitely great culprits! When you increase your alk do you see less of a downward daily swing? Also, how big is your tank?

Tank is 34 gallon. Yes, it's seems like the more alk I add the less it swings each day.

 

[drawman]

Tank is 34 gallon. Yes, it's seems like the more alk I add the less it swings each day.

How long have you had the coral for?

To me the Alk consumption seems reasonable I would just try to increase/narrow in on your daily dose to keep things stable. Then water changes should bring it up to a better/more desired level. What is the alk of the nsw for your water changes?

It's a little odd that your alk draw is so much more than your calcium. What 2 part are you using and are you mixing it to the recommended concentration? Calcium will take a lot longer to drop on a test kit so maybe you just haven't verified that consumption yet? If so, I guess you could always look for precipitation when dosing as well but I'm sure you're fine.

Mag looks good to me as well.

 

[Randy Holmes-Farley Verified Community Expert]

I'm worried the testing may be off. Tanks usually cannot drop to 4.5 dKH even with no dosing.

You gave amounts dosed, but didn't tell us what product.

 

[rock_lobster]

You need to dose more alkalinity and more often. I'm not sure if your alkalinity test is correct though because below 6 is the critical zone where coral will die rapidly. I would check against standard solution. Also that is not a lot of dosing for those euphylia assuming BRS 2part.. I'm dosing about the same in my 20 gallon jbj and it has only a few sps and one LPS.

 

[Iballhog]

Using brs two part. I test with red sea and Hanna . I also just purchased new reagents for the Hanna.

 

[Ryengoth]

I use kalk for my regular alk adjustments unless the PH is outta whack then I just dose saturated sodium bicarb. I use the ATO to dose it based on evap rate in the tank, which is fairly consistent.

 

[Ryengoth]

You can make your own colormetric testing solution but you should have a stable control source for batch tests.

https://www.epa.gov/sites/production/files/2015-08/documents/method_130-1_1971.pdf

 

[rock_lobster]

Using brs two part. I test with red sea and Hanna . I also just purchased new reagents for the Hanna.

Then if accurate you surely need to increase the dosing. Spread out multiple times a day to prevent any spikes.

 

[Ryengoth]

I would expect Ca to be in the 500 range with 1300 Mg if your alk is around 9 so maybe your issue is calcium consumption as drawman hinted to. Try dosing ionic calcium for a few days and see what swings around.

 

[Ryengoth]

Oh.. what Ca and Mg tests are you using?

 

[Iballhog]

Oh.. what Ca and Mg tests are you using?

Red Sea

 

[Ryengoth]

How long do you wait for the color to form between drops once it starts turning blue and at what point do you take the reading?

 

[Iballhog]

How long have you had the coral for?
I've had the coral for maybe 7 years, 4 years in this tank.

To me the Alk consumption seems reasonable I would just try to increase/narrow in on your daily dose to keep things stable. Then water changes should bring it up to a better/more desired level. What is the alk of the nsw for your water changes?
I think my water change alk was 7.9, I'll test it tonight when I do a water change.

It's a little odd that your alk draw is so much more than your calcium. What 2 part are you using and are you mixing it to the recommended concentration?
BRS 2 Part
Calcium will take a lot longer to drop on a test kit so maybe you just haven't verified that consumption yet? If so, I guess you could always look for precipitation when dosing as well but I'm sure you're fine.

Mag looks good to me as well.

How long do you wait for the color to form between drops once it starts turning blue and at what point do you take the reading?

For Cal and Mag, I Drop, then swirl. I'll wait at least 15 seconds before taking a reading.

Try dosing ionic calcium for a few days and see what swings around.

Thanks for the suggestion, I've never heard of this and will look into it.

I just ran another set of water tests.
Cal - 440ppm
Alk(Hanna)- 6.1
Alk(Red Sea)-6.4
Mag-1440ppm

Maybe I screwed up mixing the 2 part? if my googling is correct. The ALK solution should be 5300 dKH, and if I dilute it 1:1000ml, I should be able to check it with a test kit?

 

[Ryengoth]

Ionic calcium is the "simplest" form of Ca in solution and is readily accessible to anything that builds matter by combining only Ca ions with something else in solution or produced by the critter. Dosing carbonates are already in a balanced molecular formation with another element and must be broken down first to access the Calcium ions directly. It would be telling to know if your Magnesium drops significantly after dosing ionic ca. At least the way I thinking about it. Maybe Randy can expand or correct my thought process here? LOL

 

[Ryengoth]

Last 2 questions, which are critical to adjustments but not posted yet: PH? Salinity?

 

[Iballhog]

Last 2 questions, which are critical to adjustments but not posted yet: PH? Salinity?

I keep Salinity at 1.026 tested with a Milwaukee.
I have a ph probe, but honestly I can't remeber last time I calibrated the probe

 

[Ryengoth]

Test the PH with colormetric before you do any more adjustments. Your peaks should be closer to 8.1. What's odd is the fact that your PH is close to 8 but your alk is under 7?? That makes zero sense.

 

[rock_lobster]

I dont think the relationship is that linear. You can easily test a pH from 7.5-8.5 with alkalinity anywhere in the range from 3 to 14 dkh. No red flag there just simply need to dose more carbonate.