Alk won't rise

[rvlcf]

I have a medium to low stocked Reefer 450 about 4 months old. I am dosing Kalk in the top off at max strength of 2 teaspoons per gallon. Also dosing BRS soda ash solution every other hour through dosing pump, with BRS calcium dosing on the oppositehour. Don't know the exact amount of alk per day, but its at least 50ml. Alk reading is between 6 and 6.5 depending on the test. I have been manually adding 80 ml alk the last two days, on top of the normal dosing trying to get the alk up. I'm still getting the same readings even after dosing at least 150 ml of alk the last few days. What gives?
Params are:
Cal 420
Mg 1400
ph 8.2
sg 1.026

I'm using a Hanna alk checker. Tried two different reagents, with roughly the same results, and ran a salifert also which gives me the same readings. It's not the test kits.

Thanks in advance for the help.

 

[sk8elenex92]

I had this problem as well. I had to dose more alk. I would stop Kalk for now. Just try raising it first. Dose enough for .5 dkh and test hour later.
Also is sand getting rockkkk hard in some spots ?

 

[reeferfoxx]

It's important to not let that number fall below 6. The acidity difference between 5 and 6 is 10 times greater in acidity level. Grab separate alkalinity supplement and raise alk back to normal. Then test alk for a few weeks to see if your reduction has changed?

 

[Randy Holmes-Farley Verified Community Expert]

It's important to not let that number fall below 6. The acidity difference between 5 and 6 is 10 times greater in acidity level.

That would be true for pH 5 to 6, but not for alkalinity of 5 to 6 dKH.

 

[Randy Holmes-Farley Verified Community Expert]

I have a medium to low stocked Reefer 450 about 4 months old. I am dosing Kalk in the top off at max strength of 2 teaspoons per gallon. Also dosing BRS soda ash solution every other hour through dosing pump, with BRS calcium dosing on the oppositehour. Don't know the exact amount of alk per day, but its at least 50ml. Alk reading is between 6 and 6.5 depending on the test. I have been manually adding 80 ml alk the last two days, on top of the normal dosing trying to get the alk up. I'm still getting the same readings even after dosing at least 150 ml of alk the last few days. What gives?
Params are:
Cal 420
Mg 1400
ph 8.2
sg 1.026

I'm using a Hanna alk checker. Tried two different reagents, with roughly the same results, and ran a salifert also which gives me the same readings. It's not the test kits.

Thanks in advance for the help.

You just need to be dosing more, IMO (assuming the alk is in dKH and not meq/L)

 

[reeferfoxx]

That would be true for pH 5 to 6, but not for alkalinity of 5 to 6 dKH.

Thank you. I'm getting my things(chemistry) mixed up, again. I'm working on that lol

 

[rvlcf]

It is in Dkh.
No, sand is not getting hard.

 

[rvlcf]

Now the sand is getting hard and clumping together. Also have calcification? on equipment and walls in the sump.
Why do i need to add so much Alk? There has got to be some problem where the Alk is not available or binding to something.

 

[madweazl]

Now the sand is getting hard and clumping together. Also have calcification? on equipment and walls in the sump.
Why do i need to add so much Alk? There has got to be some problem where the Alk is not available or binding to something.

I thought that usually happened when the KH was too high; does this occur when it is too low and too high (or do I have this backwards)?

 

[Randy Holmes-Farley Verified Community Expert]

I thought that usually happened when the KH was too high; does this occur when it is too low and too high (or do I have this backwards)?

It's isn't clear what exactly is required (high pH, high alk, new sand, etc., all may help cause it), but low alk would not contribute in any way I can think of.

 

[rvlcf]

I've turned off the doser. Will see what happens. Alk last night at 6.765 dkh. Will test tonight at same time and see where it is. Still using kalkwasser in top off.

 

[Randy Holmes-Farley Verified Community Expert]

Alk doesn't drop much once it gets below 7 dKH.

 

[rvlcf]

If the alk levels off between 6 and 7 should I just dose the Kalk and leave it be? I am running a "ULNS" system with Gfo and Biopellets in seperate reactors.

 

[madweazl]

If the alk levels off between 6 and 7 should I just dose the Kalk and leave it be? I am running a "ULNS" system with Gfo and Biopellets in seperate reactors.

Perhaps you could try dosing baking soda to eliminate your kalk as a potential issue.

 

[Randy Holmes-Farley Verified Community Expert]

If the alk levels off between 6 and 7 should I just dose the Kalk and leave it be? I am running a "ULNS" system with Gfo and Biopellets in seperate reactors.

6-7 dKH is OK. Growth will be slower than 8 dKH, but that's not necessarily an important goal.

 

[rvlcf]

Just tested and went from 6.765 to 6.429 dkh in 24 hours, with only the addition of top off kalkwasser.
That equates to an additional 25ml needed of brs soda ash solution to maintain a stable level.
I know I was adding way more than 25 ml a day and yet my alk was still falling.
Will test again tomorrow and see where i am.

 

[rvlcf]

Perhaps you could try dosing baking soda to eliminate your kalk as a potential issue.

I will try that as soon as my huge top off container runs dry.